509

Pennsylvania Hospital, 8th and Spruce Sts., Philadelphia, PA 19107.

.. , . . . .

Glossary of Terms for Thoracic Radiology:Recommendations of the Nomenclature Committee of theFleischner Society1

The Fleischner Society was founded in 1969 by a group ofradiologists to honor the memory of Felix Fleischner and topromote the exchange of information between basic scientistsand clinical investigators interested in chest disease. Todaythis multidisciplinary group is best known for the Symposiaon Chest Disease that it conducts annually, but it has sought,in the words of its motto, “to advance knowledge of thenormal and diseased chest” in various other ways. The Glos-sary presented here represents one such effort.

The Glossary was originally proposed at the first generalmeeting of the Society of 1 971 in the belief that standardiza-tion of terms with respect to the description of radiographic

findings would facilitate the exchange of information. Variousmembers of the Society have contributed to its developmentover the intervening years, and though such an undertakingis never truly completed, the Glossary is now judged to besufficiently inclusive to be of general interest. The Society,therefore, authorized its publication as a report of the Nomen-

clature Committee in May 1983.The development of a glossary is a process that casts light

on both the meaning of words and on the basics of humanbehavior. The use of words, it appears, is a highly personalattribute of the individual, and any disagreement with thatusage is instinctively viewed as a personal assault: A nomen-clature committee does not need a chairman; it needs a“peace-keeping force”! It is, therefore, a great tribute to thosewho participated that they were ultimately able to put personalbias and national linguistic differences aside and to agree onthe definitions presented here.

The Committee, comprising more “splitters” than “lumpers,”has sought to identify nuances of meaning that distinguishwords of similar connotation and has systematically rejectedthe argument that “everyone says it that way” as a justificationfor the misuse of a word. It has also attempted to indicatewhether specific terms are truly descriptors or are, in fact,diagnostic conclusions; and if the latter, whether or not theycan appropriately be based solely on radiographic evidence.It is hoped that publication of this Glossary will stimulateinterest in the standardization of descriptive terminology inchest radiology, that some will adhere to the definitions pre-

sented here, and that those who do not will, at least, becomemore thoughtful in their choice of words.

Thanks are due to those members of the Society wholaunched this effort: Gordon Cumming (Midhurst, England)and E. Robert Heitzman (Syracuse, NY); to those who sus-tamed it: John J. Fennessy (Chicago, IL), Paul J. Friedman(San Diego, CA), Ronald Grainger(Sheffield, England), WilliamH. Northway, Jr. (Palo Alto, CA), and the late George Jacob-son (Los Angeles, CA); and most particularly to those onwhom fell the burden of bringing it to fruition: John H. M.Austin (New York, NY), Robert G. Fraser (Birmingham, AL),David H. Trapnell (London, England) and Morris Simon (Bos-ton, MA).

Editor’s Note

William J. TuddenhamChairman, Nomenclature Committee

The Fleischner Society

At its recent meeting in Santa Fe, the Fleischner Societyreaffirmed its hope this Glossary will prove helpful in refiningthe radiographic vocabulary for describing and thinking aboutthoracic disease. The Society also realizes these definitionsand comments on their usage (evaluations) may not satisfyall readers. A certain dogmatism has been required to reachfinal statements about terms that may be used differently by

others. To achieve a wider consensus on the acceptance ofcontroversial terms, the Society invites comments, criticisms,and suggested additions. These may be directed to the AJR

Editorial Office or to Dr. Robert Fraser (Department ofRadiology, University of Alabama Medical Center, 619 5. 19thSt., Birmingham, AL 35233). Dr. Fraser is the new chairmanof the Nomenclature Committee; the committee willsynthesize constructive suggestions into revisions in theGlossary. Readers are urged to respond to this invitation andto help the Society reduce imprecision in our vocabulary sothe complexities of thoracic disease may be better understoodand communicated.

MMF

1 Address reprint requests to W. J. Tuddenham, Department of Radiology.

AJR 143:509-517, September 1984 0361-803X/84/1433-0509 0 American Roentgen Ray Society

510 FLEISCHNER SOCIETY GLOSSARY AJR:143, September 1984

Aabscess, n, -es. 1. Pathol. An inflammatory mass

within lung parenchyma, the central part of whichhas undergone purulent liquefaction necrosis. Itmay communicate with the bronchial tree. 2.Radio!. A mass within lung parenchyma which, ifit communicates with the bronchial tree, containsa cavity. Otherwise, a pulmonary mass can beconsidered to represent an abscess in the mor-phologic sense only by inference. -Qualifiers:Expressing clinical course: acute, chronic. Ex-pressing etiology: bacterial, fungal, etc. Express-ing site of involvement: lung, mediastinal, etc. -

Evaluation: An inferred conclusion, the use ofwhich as a radiobogic diagnosis is appropriateonly with reference to masses of presumed infec-tious origin; cf. cavity.

absorber, n, -s. Radio!phys. Any object that atten-uates an x-ray beam.

acinar pattern, n, -a. Radio!. A collection of round,poorly defined, discrete or partly confluent opac-ities in the lung, each 4-8 mm in diameter andtogether producing an extended, inhomogeneousshadow. -Synonyms: rosette pattem, acinono-dose pattem (used specifically with reference toendobronchial spread of tuberculosis), alveolarpattem (inaccurate descriptor; not recom-mended). -Evaluation: An inferred conclusionusually used as a descriptor. An acceptable term.

acinar shadow, n, -a. Radio!. A round or ovoid,poorly defined pulmonary opacity 4-8 mm indiameter, presumed to represent an anatomicacinus renderedopaque by consolidation. Usuallyused only in the presence ofmany such opacities;cf. acinar pattern. -Evaluation: An inferred con-clusion sometimes applicable as a radiobogic de-scriptor.

acinus, n, -I. Anat. The part of the lung distal to aterminal bronchiole. It consists of respiratorybronchioles, alveolar ducts, alveolar sacs, alveoli,

and their blood vessels, lymphatics, and support-ing tissues.

aerate, v. 1. To fill with air. 2. To expose to air. 3.To oxygenate.

aerated, adj. 1. Inflated, filled wtih air (lungs). 2.Air-containing (paranasal sinuses). 3. Exposed toair (blood).

aeration, n. Physiol/radiol. 1. The state of contain-ing air. 2. The state or process of admitting or ofbeing filled or inflated with air. 3. The state orprocess of being exposed to air. -Qualifiers:over- (preferred) or hyper- ; under- (preferred) orhypo-. -Synonyms: inflation. See also vanilla-hen, oxygenation. -Evaluation: Acceptableterm with reference to inspiratory phase of res-piration. Inflation is preferred in sense 2.

air, n. Radio!. Gas within the body, regardless of itscomposition or site. -Synonym: gas. -Evalua-tion: The word air should be used to refer only toinspired atmospheric gas. With reference topneumothoraces, subcutaneous emphysema orthe content of the stomach, colon, etc., gas isthe preferred term.

air bronchogram, n, -a. Radio!. The radiographicshadow of an air-filled bronchus peripheral to thehilum and surrounded by airless lung (whether byvirtue of absorption of air, replacement of air orboth); a finding generally regarded as evidenceof the patency of the more proximal airway;hence, any bandlike tapering and/or branchinglucency within opacafled lung corresponding insize and distribution to a bronchus or bronchiand presumed to represent an air-filled segmentof the bronchial tree. -Evaluation: A specificfeature of radiobogic anatomy whose identity isoften inferred. A useful and recommended term.

air-fluid level, n, -s. Radio!. See fluid level.airspace, n. Anat. The gas-containing part of the

lung exclusive of the purely conducting airways,

but including the respiratory bronchioles.-adj. Pathol/Physiol/Radiol. Of or pertaining toany process believed to be confined to the ana-tomic airspace or to a part thereof(e.g., airspaceconsolidation). -Synonyms: acinar, alveolar. -

Evaluation: Inferred conclusion appropriatelybased on radiologic evidence and an acceptabledescriptor.

air trapping, n. 1. Pathophysiol. The retention ofexcess air in all or part of the lung as a result ofairway closure during the expiratory maneuver;classically implies an increasing amount of re-tamed air at equivalent expiratory positions insuccessive expiratory maneuvers. 2. Radio!. Theretention of excess air in all or in some part ofthe lung at any stage of expiration. -Evaluation:2. A specific radiologic statement to be used onlyif excess air retention is demonstrated by a dy-namic study (e.g. , inspiration-expiration radiog-raphy or fluoroscopy). Not to be used with refer-ence to ovennflation of the lung at full inspiration(total lung capacity).

airway, n. Anat. 1. A collective term for the air-conducting passages from the larynx to and in-duding the terminal bronchioles. 2. Any air-con-ducting tube or passage.-adj. Pathol/Physiol/Radiol. Of or pertaining tothe anatomic airway or a part thereof (e.g.. do-structive airway disease). -Evaluation: Inferredconclusion appropriately based on radiobogic cvi-dance. An acceptable descriptor.

alveolarizatlon, n. Radio!. The opacification of clus-

ters of minute airways (presumed to be alveoli)by a contrast agent. -Evaluation: Excessive fill-ing of peripheral airways by a contrast agentusually used for bronchography may opacity res-piratory bronchioles, but seldom alveoli. Thus,the correct term is bronchiolar filling orbronchio-lar opacification.

alveolar pore, n, -s. Anat/Physiol. A microscopiccommunication between alveoli. Together withthe canals of Lambert and direct airway anasto-moses, the alveolar pores provide for the collat-eral passage of gas or liquid from one pulmonaryunit to another; of. collateral ventilation. -Syn-onym: pore of Kohn.

anterior junction line, n. Radio!. A vertically ori-ented linear or curvilinear opacity about 1 mmwide and commonly projected on the tracheal airshadow. It is produced by the shadows of theright and left pleurae in intimate contact betweenthe aerated lungs anterior to the great vesselsand sometimes the heart; hence, it never extendsabove the suprastemal notch. -Synonyms: an-terior mediastinal septum, anterior mediastinalline. -Evaluation: A specific feature of radiologicanatomy; preferred to cited synonyms.

sortie knob, n. RadiO!. That part of the aortic archthat is seen end-on in a frontal radiograph. In thenormal, it is characterized by a sharply defined,arcuate superolateral border and lies to the leftof the trachea above the main pulmonary artery.-Synonyms: aortic knuckle. -Evaluation: Aspecific feature of radiobogic anatomy. An ac-ceptable term.

aortopulmonary window, n. 1. Anat. A mediastirtalspace bounded anteriorly by the ascending aorta;posteriorly by the descending aorta; superiorlyby the aortic arch; inferiorly by the left pulmonaryartery; medially by the left side of the trachea,left main bronchus, and esophagus; and laterallyby the left lung. Within it are situated the ductusligament. the left recurrent laryngeal nerve, lymphnodes, and fat. 2. Radio!. A zone of relativelucency in the mediastinal shadow, which is bestseen in the left anterior oblique projection andwhich correspondstothe anatomic space definedabove. On a frontal chest radiograph, the lateralmargin of this space constitutes the aortopul-monary window interface. -Synonym: aortopul-

monic window. -Evaluation: 2. A specific featureof radiologic anatomy. An acceptable term.

arterlovenous flstUla, n, -ae. 1. Pathol anat. Adirect communication between an artery and avein that bypasses the capillary bed. 2. Radio!. Ashadow complex, comprising a nodular pulmo-nary opacity associated with dilated vascularshadows, that is presumed to represent an arte-riovenous fistula in the anatomic sense. (Suchlesions are often multiple.) -Synonyms: arterio-venous aneurysm, arteriovenous malformation.Arteriovenous fistula or aneurysm refers to alesion of congenital or traumatic origin; arterio-venous malformation should be reserved for le-sions ofcongenital origin. -Qualifiers: traumatic,congenital. -Evaluation: In conventional radi-ographs, an inferred conclusion sometimes justi-fled by the radiographic evidence alone. In pub-monary arteriography, an explicit radiographicdiagnosis.

atelectasis, n. 1. Pathol phys. Less than normalkiflation ofall or part ofthe lung with correspond-ing diminution in lung volume. 2. Radio!. Radio-logic evidence of diminished volume affecting allor part of a lung, which may or may not includebss ofnormal lucency in the affected part of lung.(This finding is not to be confused with diminishedvolume produced by resection of pulmonary tis-sue.) -Qualifiers: Expressing mechanism: re-sorption (obstructive), secondary to airway ob-struction; relaxation (passive, compression), sec-ondary to the effect of an adjacent space-occu-pying process; surfactant deficit; cicatrization(scar), secondary to fibrotic contraction. Express-ing distribution: total pulmonary, bobar, segmen-tal, subsegmental, platelike, discoid, platter, bin-ear. Expressing severity: minor (mild), moderate,marked (severe), total (complete). -Synonyms:anectasis, loss of volume, collapse. Anectasis isusually used in reference to failure of lung expan.sion in the newborn; atelectasis and loss of vol-ume refer to acquired diminution in lung volumeand do not connote severity. Collapse, in Ameri-can usage, refers to total atelectasis; in Britishusage, collapse has the more general meaning ofatelectasis (2, above). -Evaluation: A conclusionconceming pathophysiobogy that is appropriatelybased on radiographic evidence alone.

attenuate, v. Radio!phys. To reduce the energy ofan x-ray beam.

attenuation, n. Radio! phys. A collective term forthe processes (absorption and scattering) bywhich the energy of an x-ray beam is diminishedIn its passage through matter.

azygoesophageal recess, n. 1. Anat. A space orrecess in the right side of the mediastinum intowhich the medial edge of the right bower lobe(crista pulmonis) extends. It is limited superiorlyby the arch of the azygos vein, posteriorly by theazygos vein in front of the vertebral column, andmedially by the esophagus and its adjacent struc-tures. (The exact relation between the medialedge of the lung and the mediastinal structuresvaries.) 2. Radio!. In a frontal chest radiograph, avertically oriented interface between air in theright lower lung and the adjacent mediastinumthat represents the medial limit of the anatomicazygoesophageal recess. -Evaluation: 2. A spa-cific feature of radiologic anatomy. The use of theterm recess to identify a linear shadow is map-propriate; medial boundary or limit or azygoeso-phageal recess is preferred.

azygos vein, n. Radio!. A slight, ovoid prominenceof the mediastinal shadow commonly seen infrontal chest radiographs in the angle formed bythe right main bronchus and the trachea. Theshadow is produced principally by the azygosveln projected end-on, but azygos lymph nodesmay contribute to it. -Evaluation: A feature ofradiobogic anatomy of some descriptive value rel-

MR:143, September1984 FLEISCHNER SOCIETY GLOSSARY 511

ative to the status of the systemic venous volumeand pressure and azygos vain flow volume; an- term.

B

band shadow, n, -s. Radio!. See linear opacity.batwlng distribution, n. RadiO!. A spatial arrange-

ment of radiographic opacities in a frontal radi-ograph that bears a vague resemblance to theshape of a bat in flight; said of coalescent, poorlydefined opacities that are nearly bilaterally sym-metric and that are confined to the central one-to two-thirds of the lungs. (Lesions that producesuch shadows are not necessarily peripheral orcentral in location.) -Synonym: butterfly distri-bution. -Evaluation: A radiologic descriptor oflimited usefulness.

blab, n, -a. 1. Patho! anat. A gas-containing spacewithin the visceral pleura of the lung. A form ofpulmonary air cyst. 2. RadiO!. A sharply demar-cated, thin-walled lucency contiguous with thepleura, usually at the lung apex. -Synonyms:type I bubla(Reid), bulla, air cyst. -Evaluation: 2.An inferred conclusion, seldom justified by theradiograph alone. Bulla or air cyst is preferred.

belle, n, -as. 1. Patho! anat. a. A sharply demar-cated region of emphysema 1 cm or more indiameter. b. An abnormal space within the lung1 cm or more in diameter that may contain onlygas (type II of Reid), or may contain, in addition,blood vessels and ruptured alveolar walls (typeIll of Reid). Aform ofpulmonary aircyst. 2. Radio!.Any sharply demarcated lucency 1 cm or more indiameter within the lung, the wall of which is lessthan 1 mm thick. -Qualifiers: small, medium,large. -Synonyms: blab, air cyst; pneumatoceleis not a proper synonym. -Evaluation: 2. Aninferred conclusion. usually justified by the radi-ographic findings. An acceptable term.

butterfly distribution, n. Radio!. See batwing dis-thbutlon. (To be distinguished from the use ofthis term in general medicine to describe thedistribution of certain cutaneous lesions.)

Ccalcific, adj. 1. Of or pertaining to deposits of

insoluble calcium salts. 2. Radio! [said of ashadow). a. Significantly moreopaquethan shad-ows of soft tissues of comparable thickness and,therefore, presumed to represent a calcified tis-sue. b. Similar in opacity to shadows of structuresof comparable thickness that are known to becalcified.

calcification, n, -S. 1. The state or process of beingrendered calcareous by the deposition of calciumsalts. 2. A calcified structure. Specifically: pul-monary calcification, n. 1. Pathophysiol. a. Theprocess by which one or more deposits of cal-csum salts are formed within lung tissue or withina pulmonary lesion. b. Such a deposit of calciumsalts. 2. Radio!. A calcific opacity within the lungthat may be organized in the sense of concentriclamination, for example, but which does not dis-play the trabecular organization of true bone. -

Qualifiers: eggshell, popcorn, etc. (q.v.) -Eval-uation: An explicit statement; may be used as adescriptor. A useful term. To be distinguishedfrom pulmonary ossification (q.v.).

calcified, adj. 1. Having undergone calcification;containing calcium safts. 2. Radio!. Containingcalcific shadows.

calcify, v. To make or to become stony or calcar-eous by the deposition or secretion of calciumsalts.

cardiac rncisura, n. Radio!. The concavity in the

left heart border seen in the frontal (or rightanterior oblique) chest radiograph just below theleft hilum and representing the junction betweenthe main pulmonary artery and the left ventricularmyocardium. The tip of the left atilal appendagemay underlie the rncisura. -Evaluation: A featureof radiobogic anatomy. An acceptable term.

sa#{241}nslangle, n. Anal/Radio!. The angle formedbetween the right and left main bronchi in a frontalchest radiograph. -Synonyms: bifurcation an-gb, angle of tracheal bifurcation. -Evaluation: Adefinitive anatomic and radiologic measurement.

cavIty, n, -lea. 1. PatPiol ens!. A gas-filled spacewithin a zone ofpulmonary consolidation or withina mass or nodule, produced by the expulsion ofa necrotic part of the lesion via the brOnchial tree.2. RadiO!. A lucency within a zone of pulmonaryconsolidation, a mass. or a nodule; hence, alucent area within the lung that may or may notcontain a fluid level and that is surrounded by awall, usually of varied thickness. -Evaluation: 2.An inferred conclusion often used as a descriptor.The term expresses pathologic anatomy withoutcausative connotation. It is a useful radiobogicdescriptor; it is not synonymous with abscess,which may exist without cavitation.

circumscribed, adj. Radio!. Possessing a corn-pletely or nearly completely visible border. -

Evaluation: An acceptable descriptor: cf. defined.coalescent, adj. Radio!. Joined together; said of

multiple opacities joined to form a single opacity,but stlH individually identifiable; cf. confluent,composite. -Evaluation: An acceptable descrip-tor.

coin lesion, n. Radio!. A sharply defined, circularopacity within the lung. suggestive of the ap-pearance of a coin and usually representing aspherical or nodular lesion. -Synonyms: pul-monary nodule, pulmonary mass. -Evaluation:A radiologic descriptor, the use of which is to becondemned. The term coin may be descriptive ofthe shadow, but certainly not of the lesion pro-ducing it.

composite, adj. Radio!. Comprising more than oneelement; said of a shadow complex made up ofmultiple contiguous or superimposed elementsthat may or may not be separately identifiable.

consolidate, V. 1. To become firm or hard (as bysolidifying). 2. To cause to become firm or hard.

consolidated, adj. Having become firm or solid;having undergone consolidation.

consolidation, n, -S. 1. Pathophysiol. a. The pro-ness by which air in the lung is replaced by theproducts of disease rendering the lung solid (asin pneumonia). b. The state of pulmonary tissueso Solidified. 2. Radio!. An essentially homoge-focus opacity in the lung characterized by littleor no loss of volume, effacement of blood vesselshadows, and sometimes by the presence of anair bronchogram (q.v.). Applicable only in anappropriate clinical setting when the opacity canwith reasonablecertainty beattributed to replace-ment of alveolar air by exudate, transudate, ortissue. -Evaluation: 2. An inferred conclusion. Auseful term when used in strict accord with thedefinitiOn above. Not to be used with referenceto any homogeneous opacity.

contrast medium, n, -Ia. RadiO!. An agent admin-istered to render the lumen of a hollow structure,vessel. or viscus more or less opaque than itssurroundforthe purposeof radiographic imaging.-Synonyms: contrast agent, opaque medium,opaque. -Evaluation: The use of contrast or dyeto refer to a contrast medium is to be condemned,as is the use of the plural form, contrast media,to refer to a single contrast agent.

cor pulmonale, n. 1. Patho! anat/Clin. Right ventric-ular hypertrophy and/or dilatation occurring as aresult of an abnormality of lung structure or func-tion. 2. Radio!. Evidence of pulmonary arterial

hypertension with or without evidence of enlarge-mont of the right heart chambers occurring inassociation with evidence of chronic lung dis-ease. -Qualifiers: acute, chronic. -Evaluation:2. An inferred radiologic conclusion that dependson radiographic signs that are usually, but notinvariably, reliable; an acceptable descriptor. Dc-spite pathology def. 1, radiologic evidence ofcardiornegaly need not be present.

cyst, n, -S. 1. Patho! anat. A circumscribed space,1 cm ormore in diameter, containing gas or liquid,whose wall is generally thin, weN defined. andcomposed of a variety of ceflular elements. 2.Radio!. A circumscribed lucency or opacity withinthe lung or mediastinurn, 1 cm or more in diam-eter, that is presumed to represent a cyst in thepathologic sense. -Qualifiers: 1. foregut (bron-chogenic. esophageal duplication); postinfection.2. air. -Evaluation: 2. This term is appropriatefor the description of any thin-walled, gas-con-taming pulmonary space of uncertain causewhose wall is more than 1 mm thick. The term isentirely nonspecific and, if possible, a more spa-cific term(bleb, bul!a,pneumatocele) is preferred.

Ddense, adj. Radio!. Possessing density (q.v.). Usu-

ally used in describing or comparing radiographsor radiographic shadows with respect to theirlight transmission. -Synonyms: black, heavilyexposed. -Evaluation: A recommended term ,rithe context defined. Should not be used in refer-ring to the opacity of an absorber to x-radiation.See opaque, opacity.

density, n, -Isa. 1. Photom/Radiol. a. The propertyof an exposedand processed photographic emul-sion thatdetermines itslight absorptlon/transmis-siori characteristics; hence: b. The opacity of aradiographic shadow to visible bight; film black-ening. 2. RadiO!. A qualitative expression of thedegree of film blackening usually expressed interms of the blackening of one film or shadowrelative to another. 3. Photom. A quantitativeexpression of the degree of film blackening de-fined as: density = bogio X intensity (incidentlight)[intensity (transmitted light); optical density.4. RadiO!. The shadow of an absorber moreopaque to x-rays than its surround; an opacity orradiopacity: 5. The degree of opacity of an ab-sorber to x-rays, usually expressed in terms ofthe nature of the absorber (e.g., bone density).6. Phys. The mass of a substance per unit vol-ume. -Synonyms: 1. light absorption. film black-ening. 4. opacity. radiopacity. -Qualifiers: 2.increased, decreased. 3. increased, decreased,maximum. 5. air, water, metal, soft tissue, bone,fat; increased, decreased, etc. -Evaluation: Indots. 1-3, the term refers to a fundamental char-acteristic of the radiograph. This use is recorn-mended. In dots. 4 and 5, the term refers to thecharacter of an absorber and has an exactlyopposite connotation with respect to film black-ening. Because of this potential confusion, theterm should never be used to mean an opacity(radiopacity).

diffuse, adj. 1. Widespread. 2. Pathophysioi.Widely distributed through an organ or type oftissue. 3. Radio!. Widespread and continuousLsaid of shadows and, by inference, of the statesor processes producing them). -Synonyms: dis-seminated, generalized, systemic, widespread. Inthe context of chest radiology, diffuse connoteswidespread, anatomically continuous, but notnecessarily complete involvement of the lung orother thoracic structure or tissue; disseminatedconnotes widespread but anatomically discontin-uous involvement; generalized connotes corn-

512 FLEISCHNER SOCIETY GLOSSARY AJR:143, September 1984

plete or nearly complete involvement, whereassystemic connotes involvement of a thoracicstructure or tissue as part of a process involvingthe entire body. -Evaluation: 3. A useful andacceptable term.-v. To spread, to extend in continuity in alldirections.

dirty chest, n. Radio!. An appearance of the lungscharacterized by acompbex ofabnormal shadowsof wide distribution and varying form and char-acter. -Synonym: dirty lung. -Evaluation: Acolloquial descriptor so indefinite as to defy ac-curate definition. To be rejected in favor of moreprecise descriptors.

disseminate, v. To spread, as seed.dissemInated, adj. 1. Widespread; sown as seed.

2. Pathophysiol. Widely but discontinuously dis-tributed through an organ or type of tissue. 3.Radio!. Widespread but anatomically discontin-uous [said of shadows and, by inference, of thestates or processes producing them]. -Eva!ua-tion: 3. A useful and acceptable term.

doubling time, n, -a. Radio!. The time in which apulmonary nodule or mass doubles in volume(increases in diameter by a factor of 1 .25): asemiquantitative expression of the growth rate ofa lesion. -Evaluation: An acceptable term. Theconcept of growth rate is of very limited value asa criterion for distinguishing benign from malig-nant nodules.

E

eggshell calcification, n. Radio!. Thin, sharply do-fined, curvilinear, calcific opacities occurring inthe periphery of a lesion or anatomic structuresuch as a lymph node. -Synonym: curvilinearcalcification. -Evaluation: An acceptable radio-logic descriptor.

embolism, n. 1. Pathol. The complete or partialdestruction ofthe lumen ofa blood vessel, usuallyan artery, by the sudden impaction of foreignmaterial carried in the blood stream; cf. infarc-lion. 2. Radio!. A complex of radiographic and/orscintigraphic abnormalities presumed to repre-sent embolism in the pathologic sense. -Evalu-ation: An inferred conclusion that in some casescan be based on radiographic or scintigraphicevidence alone.

embolizatlon, n. Pathol. The pathologic process bywhich the lumen of a blood vessel is suddenlyobstructed by blood clot or foreign material car-ried out in the bloodstream. -Qualifiers: thera-peutic, referring to the technique by which thelumen of a blood vessel is deliberately occludedby the introduction offoreign objects or materials.

embolus, n. -i. 1. Patho!. A blood clot or mass offoreign material that has been carried in thebloodstream and that partly or completely cc-ciudes the lumen of a blood vessel; Cf. thrombus.2. Radio!. A lucent defect or obstruction withinan opacifled vessel presumed to represent anembolus in the pathologic sense. -Qualifiers:Expressing clinical course: acute, chronic. Ex-pressing nature of embolic material: air, fat, am-niotic fluid, parasitic, neoplastic. tissue, foreignmaterials (e.g., iodized oil, mercury, talc). Miscel-laneous: septic, therapeutic, paradoxic. -Eva!-uation: 2. A radiologic conclusion that may appro-priately be based on arteriographic evidencealone.

emphysema, n. 1. Pathol anat. a. A morbid condi-tion of the lung characterized by abnormally cx-panded air spaces distal to the terminal bron-chicle with or without destruction of the air-spacewalls (per Ciba Conference, 1959). b. As above,but “with destruction of the walls of involved airspaces� specified (per World Health Organiza-tion, 1961 , and American Thoracic Society

[ATS], 1962). 2. Radio!. Hyperinflatlon (q.v.) ofall or part of one or both lungs. with or withoutassociated alteration in pulmonary vascular pat-tem, presumed to represent morphologic emphy-serna; applicable only in an appropriate clinicalsethng and, in the sense of the ATS definition,not applicable to spasmodic asthma or cornpen-satory hyperinflation. -Qualifiers: Morpho!. con-tribobular, panlobular, paraseptal, focal-dust, al-veolar duct, paracicatricial, etc.; Clin. local, gen-oral, bobar, segmental, senile, compensatory, sur-gical; mild, moderate, severe, etc. -Synonyms:None; overinflation and hyperaeration are notstrictly synonymous with emphysema; emphy-sematous lungs are invariably overinflated, butovermnflated lungs are not invariably emphyse-matous. -Evaluation: 2. An inferred conclusionacceptable only if used in strict accordance withthe definition above.

exudate, n, -S. 1. Pathophysiol. a. Highly protelna-000us fluid that may or may not contain inflam-matory cells, is derived from the blood, is elabo-rated as part of the inflammatory response of thelung. pleura, or other tissues, and is deposited in

extravascular tissue spaces and on tissue sur-faces. b. An accumulation ofsuch fluid. 2. Radio!.A poorly defined opacity in the lung that neitherdestroys nor displaces its gross architecture; ap-plicable only to an opacity that, on the basis ofclinical or other evidence, can be attributed withreasonable certainty to a pulmonary infection orother inflammatory process. -Evaluation: 2. Aninferred conclusion usually used as a descriptor.A useful and acceptable term when used in ac-cordance with the definition above. To be distin-guished from transudate.

exudation, n. The process by which exudate (vs.)is formed.

exudative, adj. Of or pertaining to an exudate.

Ffibrocalcific, adj. Radio!. Of or pertaining to sharply

defined, linear, and/or nodular opacities contain-ing cabclficalion(s)(q.v.), usually occurring in theupper lobes and presumed to represent old gran-ubornatous lesions-Evaluation: A widely usedand acceptable radiobogic descriptor.

flbronodular,adj. Radio!. Oforpertainingto sharplydefined, approximately circular opacities, occur-ring singly or in dusters, usually in the upperlobes of the lungs and associated with linearopacities and distortion (retraction) of adjacentstructures. A finding usually presumed to repre-sent old granubomatous disease, but no inferenceconcerning the activity of such a lesion is justifiedon the basis of a single radiograph-Evaluation:An inferred conclusion usually used as a radio-logic descriptor. Its use is not recommended.

fibrosis, n. 1. PotPie!. a. Cellular fibrous tissue ordense acellular collagenous tissue. b. Theprocess of proliferation of fibroblasts leading tothe formation of fibrous or collagenous tissue. 2.Radio!. Any opacity presumed to represent fi-brous or collagenous tissue; applicable to linear,nodular, or stellate opacities that are sharplydefined, that are associated with evidence of lossof volume in the affected part of the lung and/orwith deformity of adjacent structures, and thatshow no change over a period of months oryears. Also applicable with caution to a diffusepattem of opacity if there is evidence of progres-siveboss oflung volumeor ifthe pattern of opacityis unchanged over time, with or without compen-satory overmnflation.-Evaluation: 2. An inferredconclusion often used as a radiobogic descriptor.An acceptable term if used in strict accordancewith the criteria cited.

fIbrotic, adj. 1. Pathol. Of or pertaining to fIbrosis

(vs.). 2. Radio!. Of or pertaining to any opacityor pattern of opacities presumed to representfibrous tissue-Evaluation: 2. An inferred conclu-sion usually used as a radiobogic descriptor. Ac-ceptable if used in strict accordance with thecriteria cited under fibrosis (vs.).

fIlm, n, -a. RSdiOL 1. The generic term for a radia-hon-recording medium consisting of a photon-sensitive emulsion coated on a flexible celluloseacetate or Mylar support. 2. A specific radiation-recording medium coated with an identified emul-

sion and having particular, predictable imagingproperties. (�This film is more sensitive thanthat.”) 3. A unit or sheet of such a radiationrecording medium. 4. A processed radiograph(col!oq).-Evaluation: Film properly refers to theunexposed, unprocessed raw material of radi-ographic recordings; radiograph properly refersto the exposed, processed product of radi-ographic recording. The use of film as a synonymfor radiograph in referring to an exposed andprocessed diagnostic recording is not recoin-mended.-v, -ad, -ing. Radio!. To record or examineradiographically; to expose a radlograph.-Syn-onyms: to x-ray, to radiograph, to expose a ra-diograph, to record a radiograph-Evaluation:Film in this sense is usually used in contradistinc-tion to screen, to distinguish a radiographic froma fluoroscopic procedure. Its use is acceptable(particularly in British usage), but to expose aradiograph is preferred.

film contrast factor, n. Radio! phys. The slope ofthe film characteristic curve (a plot of density vs.bog relative exposure); hence, the rate of changeof film blackening (optical density) as a functionof exposure-Synonyms: film gamma, film gra-dent; these terms are not strictly synonymouswith film contrast factor, but are closely relatedto it in meaning-Evaluation: A fundamentalcharacteristic of a radiographic emulsion.

filter, n, -s. 1. Radiolphys. A device (usually sheetaluminum or copper) placed in the primary x-raybeam for the purpose of preferentially absorbinglow-energy photons that otherwise would be ab-sorbed by the patient. 2. A shaped metallic ab-sorber placed in the primary x-ray beam to atten-uate certain areas of the beam preferentially. Seetrough filter-Qualifiers: 1. primary, secondary,mherent, added; 2. trough, wedge.

filtration, n. RadiO! phys. The process of attenuat-rng the x-ray beam preferentially with respect tophoton energy and/or spatial distribution-Qua!-ifiers: inherent, added, total-Evaluation: A fun-damental concept of radiation physics of clinicaliniportance in radiation protection.

fissure, n, -S. 1. Mat. Any cleft or infolding of thesurface of a structure; hence, in the lungs, themfolding of visceral pleura that separates onelobe or part of a lobe from another. a. Interlobarfissures are produced by two layers of visceralpleura. b. Anomalous fissures may be completeor incomplete, usually separate segments ratherthan lobes and, in the case of the azygos fissure,may be formed by two layers of visceral andparietal pleura. 2. Radio!. A linear opacity normally1 mm or less in width that corresponds in positionand extent to the anatomic separation of pulmo-nary lobes or segments-Qualifiers: minor, ma-jor, horizontal, oblique, accessory, anomalous,azygos, inferior accessory-Synonym: la. inter-lobar septa.-Eva!uation: 2. A specific feature ofradiobogic anatomy; an appropriate and usefulterm.

Flelschner line, n, -a. Radio!. A straight, curved, orrregular linear opacity that is Visible in multipleprojections; is usually situated in the lower halfof the lung; is usually approximately horizontal,but may be oriented in any direction; and may ormay not appear to extend to the pleural surface.

AJR:143, September1984 FLEISCHNER SOCIETY GLOSSARY 513

Such lines vary markedly in length and width;their exact pathologic significance is unknown.-Qualifiers: In radiologic description, the location,length. width, and orientation of such a lineshould be specified-Synonyms: None; plate-like, discoid, and platter atelectasis should not beused as synonyms. In the absence of clear his-tologic evidence of the significance of F. lines,this inferred identification of such lines with aform of atelectasis is unwarranted-Evaluation:An acceptable term. The term linearopacity prop-erlyqualified with respectto location, dimensions,and orientation is to be preferred, however.

fluffy, adj. Radio![said of opacities]. Poorly defined,lacking clear-cut margins; resembling down orfluff. -Synonyms: shaggy, poorly defined. -

Evaluation: An imprecisedescriptoroflimited use-fulness.

fluid bevel, n. Radio!. The shadow complex pro-duced by a horizontal x-ray beam traversing aspace containing both gas and liquid or, lessoften, two liquids of different attenuation char-acteristics. Hence, a horizontal interface betweenzones of relative lucency above and opacity be-low. -Synonyms: air-fluid level (fluid level is pro-ferred), gas-fluid level, gas-liquid level. -Evalu-ation: A useful and acceptable descriptor.

Ggas shadow, n. 1. Pathophysiol/Clin. A shadow of

such exceptional lucency relative to adjacent an-atomic shadows and to the inferred thickness ofthe absorber as to exclude the possibility of itsrepresenting a solid or liquid absorber. -Evalu-ation: An inferred conclusion appropriately basedon radiographic evidence alone and useful as adescriptor.

ground-glass, adj. Radio! [usually with appear-ance]. Any extended, finely granular pattem ofpulmonary opacity within which normal anatomicdetails are partly obscured; from a fancied resem-blance to etched or abraded glass. -Evaluation:A nonspecific radiologic descriptor oflimited use-fulness.

Hheart failure, n. 1. Pathophysio!/Cin. Inability of the

heart to satisfy the circulatory needs of the tis-sues of the body without raising ventricular end-diastolic pressure above 1 2 mm Hg, even thoughfilling pressures may be adequate. 2. Radio!. Thepresence within the thorax of a complex of signsof pulmonary or systemic venous hypertensionincluding, but not limited to, cardiomegaly, pul-monary bboodflow redistribution, interstitial and/or alveolar edema, generalized decrease in pub-monary volume, and, in the case of right ventric-ular failure only, generalized systemic venousdistension. -Qualifiers: Expressing course ofdevelopment: acute, chronic. Expressing natureof involvement: left, right, biventricular. -Syn-onyms: cardiac decompensation, cardiac failure,congestive heart failure. -Evaluation: 1. An ac-ceptabbe term used in the clinical and pathophys-iobogic sense. 2. An inferred conclusion justifiedby the presence of cited radiographic findings inan appropriate clinical setting. Cardiac decom-pensation or congestive heart failure are the pro-ferred terms.

hernia, herniation, n. Clin/Patho! anat/Radio!. Theprotrusion of all or part of an organ or tissuethrough an abnormal opening. -Evaluation: Aninferred conclusion to be used only within theprecise terms of the definition. Thus, the word isappropriate in relation to a diaphragmatic hernia,

but should not be used with reference to pulmo-nary overinflation with mediastinal displacement.

hilum, n, -a. 1. Anat. A depression or pit in that partof an organ where the vessels and nerves enter.2. Radio!. The composite shadow at the root ofeach lung produced by bronchi, arteries andveins, lymph nodes, nerves, brOnChial vessels,and associated areolar tissue. -Synonyms:hilus, -I, lung root. -Evaluation: 2. A specificelement ofradiologic anatomy. Hilum and hila arepreferred to hilus and hili. -adj. hilar.

homogeneous, adj. Radio!. Of uniform opacity andtexture throughout. -Antonyms: inhornoge-neous, nonhomogeneous, heterogeneous. -

Evaluation: An acceptable radiologic descriptor.lnhomogeneous is the preferred antonym as adescriptor of radiographic shadows. -n. home-�y.

honeycomb pattern. n. 1. Patho!. A multitude ofirregular cystic spaces in pulmonary tissue thatare generally lined with bronchiolar epitheliumand have thickened walls composed of densefibrous tissue, with or without areas of chronicinflammation. 2. Radio!. A number of closely ap-proximated ring shadows representing air spaces5-10 mm in diameter with walls 2-3 mm thickthat resemble a true honeycomb; a finding whoseoccurrence implies “end-stage lung. -Syno-nyms: None; coarse reticular pattern and coarsereticulonodular pattem are sometimes used assynonyms, but are inaccurate descriptors in thiscontext and are not recommended. -Evaluation:A radiobogic desctiptorthat has been loosely usedin the past and, therefore, with imprecise mean-ing. It is recommended that it be used strictly inaccordance with the dimensional limits citedabove, in which case it will have specific signifi-canoe.

Hounsfield unit, n, -a. Radio!phys. The unit (‘/�ooo)of an arbitrary scale on which the x-ray attenua-hon of air, water, and compact bone are definedto be -1000, 0, and +1000, respectively. Eachsuch unit represents 0.1% difference in attenua-tion with respect to that of water. Abbr: H.

hyperemia, n. 1. Patho!. An excess of blood in apart of the body; engorgement. 2. Physiol. In-creased blood flow as part of the inflammatoryresponse. 3. Radio!. Apparent increase in numberor caliber of small vessels secondary to an inflam-matory process. ynonym: pleonemia. -Eva!-uation: An inferred conclusion appropriately usedas a descriptor only in arteriography. - adj.hyperemic.

hypertension, n. Clin. Greater than normal systolicand/or diastolic pressure within the systemic orpulmonary vascular bed. Generally accepted em-pirical boundary levels are as follows: systemicarterial h., >1 40 mm Hg systolic, >90 mm Hgdiastolic; systemic venous h., >12 mm Hg; pul-monary arterial h., >30 mm Hg systolic, >15mm Hg diastolic; pulmonary venous h., >1 2 mmHg. -Evaluation: An inferred conclusion, but ox-cept in the case of systemic arterial hypertension,it can be approximated with useful accuracy onthe basis of radiologic evidence.

infarct, n, -S. 1. Patholanat. a. A region of ischemicnecrosis surrounded by hyperemic tissue result-meg from occlusion of the region’s feeding vessel,usually by an embolus; a complete infarct. b. Aregion of tissue injury and hemorrhage resultingfrom occlusion of the region’s feeding vessel,usually by an embolus; an incomplete infarct. 2.Radio!. A pulmonary opacity that by virtue of itstemporal development and clinical setting is con-sidered to result from thromboembolic occlusion

of a feeding vessel. Such an opacity is commonly,but not exclusively, hump-shaped and pleural-based when seen in profile; poorly defined andround when viewed en face. (Subsequent eventsmay establish that the opacity was the result ofeither hemorrhage or tissue necrosis.) -Syno-nym: infarction. -Evaluation: 1. Infarct is pro-ferred to infarction in this sense. 2. An inferredconclusion, which, in the proper clinical sethng,may be based on the radiograph. The wordshould not be used in the absenceof a pulmonaryopacity.-V. -ad. Pathol. To produce an infarct, def. 1above.

infarction, n, -a. 1. Pathol physiol. The process ofinfarct formation. 2. Patho! anat. An infarct.

bnflhtrate, n, -a. 1. Pathophysiol. a. Any substanceor type of cell that occurs within or spreadsthrough the interstices (interstitium and/or alveoli)of the lung, that is foreign to the lung, or thataccumulates in greater than normal quantitywithin it. b. An accumulation of such a substanceor type of cell. 2. Radio!. a. A poorly definedopacity in the lung that neither destroys nor dis-places the gross morphology of the lung and ispresumed to represent an infiltrate in the patho-physiologic sense. b. Any poorly defined opacityin the lung. -Evaluation: Majority: An inferredand often unwarranted conclusion used as adescriptor. The term is almost invariably used insense 2b, in which it serves no useful purpose,and lacking a specific connotation is so variablyused as to cause great confusion. Its use as adescriptor is to be condemned. Minority: Werethe term to be used in strict accordance withdefinition 2a, it would be a useful descriptor todistinguish processes that do not distort lungarchitecture from expanding processes that do.-v. 1. To penetrate the interstices of. 2. Tospread or cause to spread by infiltration.

infiltrated, adj. 1. Having entered or spread bypenetration of the interstices of a tissue. 2. Hay-rng undergone infiltration.

infiltration, n. 1. The process by which substancesand/or cells spread through lung tissue via itsmterstices without destroying or displacing itsnormal architecture. 2. See infiltrate. def. lb.

inflate, v. To expand, to swell with gas.inflated, adj. Expanded or filled with gas. -Quali-

tiers: See below.inflation, n. Ptiysio!/Radio!. The state or process of

being expanded or filled with gas; used specifi-cally with reference to the expansion of the lungswith air. -Qualifiers: over- (preferred) or hyper-;under- (preferred) or hypo-. ynonyms: aera-ton, inhalation, inspiration, ventilation. Inflationconnotes expansion with gas or air. Aerationconnotes the admission of air, exposure to air.Inhalation refers specifically to the act of drawingair into the lungs in the process of breathing (asopposed to exhalation); and inspiration with ref-erence to breathing, is similar in connotation.Ventilation connotes both the intake and expub-sin of air from the lungs. -Evaluation: The wordinflation avoids the confusion that surrounds themeanings of aeration and ventilation as a resultof common misusage. It is the preferred term.

interface, n. Radio!. The boundary between theshadows of two juxtaposed structures or tissuesof different texture or opacity. -Synonyms:edge. border, silhouette, junction. -Evaluation:A useful radiologic descriptor.

interstitlum, n. l.Anat/Radio!. Acontinuum of looseconnective tissue throughout the lung comprisingthree subdivisions: (i) the bronchovascular (ax-lab), surrounding the bronchi, arteries, and veinsfrom the lung root to the level of the respiratorybronchiole; (2) the parenchymal (acinar). situatedbetween alveolar and capillary basement mom-branes; and (3) the subpleural, situated beneath

514 FLEISCHNER SOCIETY GLOSSARY AJR:143, September1984

the pleura as well as in the interlobar septa. -

Synonym: interstitial space. -Evaluation: A use-ful anatomic term. The interstitium of the lung isnot normally visible radiographically; it becomesvisible only when disease(e.g., edema) increasesits volume and attenuation. -adj. Interstitial.

K

Kerley line, n, -5 [usually in the plural]. Radio!. a.A septal line (q.v.). b. A linear opacity, which,depending on its location, extent, and orientation,may be further classified as follows: K. A line: Anessentially straight linear opacity 2-6 cm longand 1-3 mm wide, usually situated in an upperlung zone, that points toward the hilum centrallyand is directed toward, but does not extend to,the pleural surface peripherally. K. B line: Astraight linear opacity 1 .5-2 cm long and 1-2mmwide, usually situated at the lung base and orb-ented at right angles to the pleural surface withwhich it is usually in contact peripherally. K. Clines [always in the plural]: A group of branching,linear opacities producing the appearance of afine net, situated at the lung base and represent-ing K. B lines seen en face. -Synonyms: septallines, lymphatic lines. Except when it is essentialto distinguish A, B, and C lines, the term seota!line is to be preferred. Lymphatic line is anatom-ically inaccurate and should never be used. -

Evaluation: A specific feature of pathologic/radio-logic anatomy. An acceptable but not preferredterm.

Lline, n. Radio!. An extended longitudinal shadow (in

the lung or mediastinum, an opacity) no greaterthan 2 mm in width; cf. stripe. -Evaluation: Auseful term appropriately used in the descriptionof radiographic shadows within the mediastinum(e.g., anteriorjunction line)orlung(e.g., interlobarfissures).

linear opacIty, n, -*5. Radio!. A shadow resem-bling a line; hence, any elongated opacity ofapproximately uniform width. -Qualifiers: Thelength, width, anatomic location, and orientationof such a shadow should be specified. -Syn-onyms: line, line shadow, linear shadow, bandshadow. Band shadow and line shadow havebeen used by some to identity elongated shad-ows more than 5 mm wide and less than 5 mmwide, respectively. Linear opacity qualified by astatement of specific dimensions is to be pro-ferred. -Evaluation: Ageneric radiologicdescnp-tor of great usefulness. The term includes a va-riety of linear shadows whose anatomic location,orientation, and dimensions imply their specificanatomic or pathologic significance (e.g., septallines). Unear opacity is to be preferred to morespecific anatomic or pathologic terms (e.g., dis-cold atelectasis), unless the true nature of theshadow is known or can be inferred with reason-able certainty.

bobar, adj. Anat/Radiol. Of or pertaining to a lobe.lobe, n, -5. 1. Mat/Radio!. One of the principal

divisions of the lungs (usually three on the right,two on the left) each of which is enveloped byvisceral pleura except at the lung root and in anyarea of developmental deficiency where a fissureis incomplete. 2. Radio!. One of the principaldivisions of the lungs (usually three on the right,two on the left) that are separated in whole or inpart by pleural fissures.

lobular, adj. Anat. Of or pertaining to a pulmonarylobule.

lobule, n, -a. Mat. A unit of lung structure. 1.

Primary: The terminal unit of an acinus; the partof the lung distal to the terminal respiratory bron-chiole. It comprises alveolar ducts, alveolar sacs,alveoli, and their accompanying blood vessels,lymphatics, and supporting tissues. 2. Second-ary: A variable number of acini (usually 3-5)bounded, in mostcases, bythin connective tissuesepta. -Evaluation: 1. Acinus is the preferredanatomic/physiologic unit of lung structure. 2.The word lobule when unmodified refers to asecondary lobule. The concept of the primarylobule as defined has been largely abandoned.

bocal, adj. Radio!. Occupying orconfined toa limitedspace within a defined structure; cf. circum-scribed. -Synonyms: localized, focal. -Mto-nyms: generalized, general, widespread. -Eval-uation: An acceptable descriptor.

lucency. n, -lee. Radio!. 1. The capacity to transmit

light (translucency); hence, by extension, the ca-pacity to transmit x-radiation. 2. The degree of x-ray transmission of an object, usually expressedin terms of transmission of one object relative toanother. 3. The shadow of an absorber thatattenuates the primary x-ray beam less effec-tively than do surrounding absorbers. Hence, ina radiograph, any circumscribed area that ap-pears more nearly black (of greater photometricdensity) than its surround. Usually applied to theshadows of air or fat when surrounded by moreeffective absorbers such as muscle, exudate, etc.

ynonyms: translucency, transradiancy. -

Evaluation: This term, used by analogywith opec-ity, is acceptable in American usage, although itis etymobogically indefensible. In British usage,transradiancy is preferred.

lucent, adj. Radio!. Capable of transmitting radiantenergy; specifically, x-radiation.

lymphadenopathy, n. Clin/Patho! anat/Radiol. Anyabnormality of lymph nodes; by common usage,usually restricted to enlargement oflymph nodes.-Synonyms: lymph node enlargement (pro-ferred), adenopathy. -Evaluation: Lymph nodesare not glands. Lymphadenopathy and ado-nopathy are, therefore, inappropriate terms andany reference to lymph glands is to be con-damned.

M

marking, n, -S [usually in the plural]. Radio!. Avague descriptor variously used with referenceto: (1) the shadows produced by normal pulmo-nary blood vessels; (2) the shadows produced bya combination of normal pulmonary structures(blood vessels, bronchi, etc.), or (3) abnormalpulmonary shadows of no specific characteristicsof significance. -Synonyms: opacity, [usually]linear opacity. - Qualifiers: The type, dimen-sions, and anatomicdistribut,on of such shadowsshould be specified (e.g., bronchovascular, tra-becular). The term should not be used withoutqualification. -Evaluation: When used alone, avague descriptor of no value; not recommended.With proper qualifIcation, the term is acceptable,but opacity or shadow is usually to be preferred.

mass, n, -es. 1. Morpho!/Gen’lmed. Any cOllectionof tissue differentiated from surrounding tissues.2. Radio!. Any pulmonary or pleural lesion repro-sented in a radiograph by a discrete opacitygreater than 30 mm in diameter (without regardto contour, border characteristics, or homogene-ity). but explicitly shown or presumed to be cx-tended in all three dimensions. -Qualifiers:Should always be qualified with respect to size,location, contour, definition, homogeneity, opac-ity, and number. -Synonyms: None; of. nodule.-Evaluation: 2. A useful and recommended do-scriptor.

mlliary pattern, n, -a. Radio!. A collection of tiny

discrete pulmonary opacities that are generallyuniform in size and widespread in distribution andeach of which is 2 mm or less in diameter. -

Synonym: micronodular pattern. -Evaluation: Anacceptable descriptor without causative conno-tation.

mucold impaction, n. Pathol/Radiol. A broad linearand/or branching opacity (I-, Y-, or V-shaped)caused by the presence of thick, tenacious mu-cus within a proximal airway (bobar, segmental,or subsegmental bronchus) and usually associ-ated with airway dilatation. -Evaluation: An in-ferred conclusion without precise causative con-notation. A useful descriptor.

MiiIer maneuver, n. Physiol. Inspiration against aclosed glottis, usually, but not necessarily, froma position of residual volume, for the purpose ofproducing transient decrease in intrathoracicpressure.

Nnodular pattern, n. Radio!. A cOllection of innumer-

able, small, roughly circular, discrete pulmonaryopacities ranging in diameter from 2 to 10 mm,generally uniform in size, widespread in distribu-tion, and without marginal spiculation; cf. reticu-bonodular pattern. -Evaluation: An acceptableradiologic descriptor without specific pathologicor causative implications. The size of the nodulesshould be specified, either as a range or as anaverage.

nodule, n, -s. 1. Morphol/Gen’l med. Any small,nearly spherical collections of differentiated tis-sue. 2. Radio!. Any pulmonary or pleural lesionrepresented in a radiograph by a sharply defined,discrete, nearly circular opacity 2-30 mm in di-ameter. - Qualifiers: Should always be qualifiedwith respect to size, location, border character-istics, number, and opacity. -Synonym: coinlesion (q.v.); cf. mass. -Evaluation: A usefuland recommended descriptor to be used in pref-erence to coin lesion.

0

oligemia, n. 1. Physio!. Less than normal blood flowto the lungs or a part thereof. 2. Radio!. Generalor local decrease in the apparent width of visiblepulmonary vessels, suggesting less than normalblood flow. -Qualifiers: acute, chronic, local,general. -Synonym: reduced blood flow. -

Evaluation: An inferred conclusion appropriatelybased on the radiographic appearance and usu-ally used as a descriptor. An acceptable term. -

adj.OligemiC.opacIty. n. -bee. Radio!. 1. ImpervIousness to ra-

dent energy; specifically, x-rays; the capacity toattenuate an x-ray beam. 2. The degree of x-rayattenuation produced by an absorber, usuallyexpressed in terms of the attenuation of oneabsorber relative to another. 3. The shadow ofan absorber that attenuates the x-ray beam moreeffectively than do surrounding absorbers.Hence, in a radiograph, any circumscribed areathat appears more nearly white (of lesser photo-metric density) than its surround. Usually appliedto the shadows of nonspecific pulmonary colbec-tions of fluid, tissue, etc., whose attenuation cx-coeds that of the surrounding aerated lung. -

Synonym: 3. radiopacity; cf. density. -Evalua-tion: 3. An essential and recommended radiobogicdescriptor. In the context of radiologic reporting,radiopaque is acceptable but appears redundant,particularly since radio- does not serve to distin-guish between the opacity of an absorber to x-rays and opacity of a radiographic shadow to

AJR:143, September 1984 FLEISCHNER SOCIETY GLOSSARY 515

visible light rays. Radiopaque is preferred in But-ish usage, nevertheless. Density (q.v.) shouldnever be used in this context.

opaque, n, -S. Radio!. That which is opaque (Webs-ter). Specifically, a contrast medium that isopaque to x-rays. -Synonyms: contrast me-diem, contrast agent, contrast material. -Eval-uation: A concise and acceptable term. Contrastmedium, agent, and material are preferred, how-ever. NB.: The terms contrast and contrast me-dia (when referring to a single agent) are colbo-quial, grammatically incorrect, and should not beused. -adj. Radio!. Impervious to x-rays. -

Synonym: radlopaque. -Evaluation: Opaque andradiopaque are both acceptable terms; opaque ispreferred. See opacity.

ossific, adj. Of or pertaining to bone.ossification, n, -5. The state or process of being

ossified. Specifically: pulmonary ossification, n.1. Pathophysiol. a. The process by which tra-becubar bone is formed within lung tissue. b. Thestate in which trabeCUlar bone exists within thelung tissue. c. A mass orfocus of trabecular boneoccurring in lung tissue. 2. Radio!. Cabciflc opac.ities within the lung that represent trabecularbone; applicable to disseminated calcific opacitiesthat (1) display morphologic characteristics offrabectiar bone (i.e., trabeculation and a definedcortex) or, more often, (2) occur in associationwith a lesion known histologically to producetrabectilar bone within lung (e.g., mitral stenosis).-Synonyms: ossific nodulation, ossific nod-ube(s). -Evaluation: 2(i). A primary radiobogicdiagnosis. 2(2). An inferred conclusion. In eithercase, a useful radiobogic term; to be distinguishedfrom pulmonary calcification.

ossified, adj. Having been changed into bone.ossify, v. To change into or form bone.

p

parasplnal line, n, -s. Radio!. A vertically orientedinterface usually seen in a frontal chest radi-ograph to the left and rarely to the right of thethoracic vertebral column. It extends from theaortic arch to the diaphragm and represents con-tact between aerated lung (of a lower lobe) andadjacent mediastinal tissues. On the left, theanatomic interface is situated posterior to thedescending aorta, and its radiographic shadow isusually seen between the left lateral margins ofthe aorta and spine. -Synonyms: left paraspinalpleural reflection, left paraspinal interface. -

Evaluation: A specific feature in radiobogic anat-omy. Either of the synonyms cited is preferred toparaspinalline, inasmuch as the shadow, in fact,represents an interface, not a line.

parenchyma, n. 1. Anat. The gas-exchanging partof the lung consisting of the alveoli and theircapillaries, estimated to constitute about 90% oftotal lung volume. 2. Radio!. The lung exclusiveof visible pulmonary vessels and airways. -

Evaluation: A useful anatomic concept. An ac-ceptable radiologic descriptor. -adj. parenchy-matous.

phantom tumor, n, -s. Radio!. The shadow pro-duced by a local COlleCtiOn of fluid in one of theinterbobarfissures, usually possessing an ellipticalconfiguration in one projection (e.g.. the lateral)and a round configuration in the other (e.g.. thefrontal view). It is commonly caused by cardiacdecompensation and usually disappears after ap-propriate therapy. -Synonyms: vanishing tumor,pseudotumor. -Evaluation: A diagnostic conclu-sion that can only be inferred from a single radi-ograph, but may be explicit by the presence ofserial radiographs. In the latter case, it is anacceptable radiobogic descriptor.

plateilke atelectasls, n. Radio!. A linear or planar

opacity of uncertain significance, presumed torepresent diminished volume in part of the lungseen end-on. -Synonyms: platter, linear, or dis-cold atelectasis. -Evaluation: An inferred con-clusion, usually not subject to proof and oftenunwarranted. Its use as a descriptor is not rec-ommended. Linear opacity, planar opacity, etc.are preferred.

pleonemla, n. 1. Physiol. Increased blood flow tothe lungs or a part thereof. 2. Radio!. General orlocal increase in the apparent width of visiblepulmonary vessels, suggesting greater than nor-mel blood flow. -Synonyms: hyperemia, in-creased blood flow. -Evaluation: An inferredconclusion appropriately based on the radi-ographic findings alone. Because pleonemiaserves to distinguish increased blood flow ofother causes from increased blood flow resultingfrom inflammation (hyperemia), it is the preferredterm in this sense. -adj. pbeon.mlc.

pneumatocele, n, -s. 1. Pathol anat. a. A thin-walled. gas-filled space within the lung, usuallyoccurring in association with acute pneumonia(most commonly of staphybococcal origin) andalmost invariably transient. b. A form of pulmo-nary air cyst. 2. Radio!. An approximately round,transient lucency within the lung that is usuallyassociated with, arid adjacent to, a zone of re-solving pulmonary consolidation that is presumedto represent a pneumatocele in the pathologicsense. -Evaluation: 2. An inferred conclusion.An acceptable descriptor only if used in accord-ance with the precise definition.

pneumomedlastlnum, n. 1. Patho!. A state char-acterized by the presence of gas in mediastinaltissues outside the esophagus and tracheobron-chial tree. 2. Radio!. The presence ofone or moregas shadows within the mediastinum that do notcorrespond in position and contour with gas inthe esophagus or tracheobronchial tree. -Qua!-ifiers: spontaneous, traumatic, diagnostic. -

Synonym: mediastinal emphysema. -Evalua-tion: A diagnostic conclusion appropriately basedon radiologic findings alone. Pneumomediastinumis preferred to mediastinal emphysema.

pneumonia. n, -s. 1. Pathol. Infection of lung par-enchyma and/or interstitium. 2. Radio!. COnSOIi-dation or any ofvarious otherforms of pulmonaryopacification presumed to represent pneumoniain the pathologic sense. -Synonym: pneumoni-tis. -Qualifiers: Expressing temporal course:acute, chronic. Expressing type of pulmonaryinvolvement: airspace, bobar, interstitial, broncho-(pneumonia plus bronchitis). Expressing cause:bacterial, viral, fungal. mycoplasma. -Evalua-tion: An inferred conclusion; pneumonia is thepreferredgeneric term.

pneumoperlcardium, ni. Pathol. A state charac-terized by the presence of gas within the pericar-dial space. 2. Radio!. The presence of gas withinthe pericardium; visible only where the gasshadow is seen in profile: laterally in the frontalview, anteriorly or posteriorly in the lateral projec-tion. -Evaluation: A diagnostic conclusion ap-propriately based on radiobogic findings alone.

pneumothorax, n, -aces. 1. Pathol. A state char-acterized by the presence of gas within thepleural space. 2. Radio!. The presence of a gasshadow between the peripheral margin of thelung (visceral pleura) and the chest wall, cia-phragm, or mediastinum(parietal pleura). -Qual-ifiers: spontaneous, traumatic, diagnostic, ten-sion.� -Evaluation: A diagnostic conclusion ap-propriately based on radiobogic evidence alone.

popcorn calcification, n. Radio!. A cluster ofsharply defined, irregularly lobulated, calcificopacities suggesting the appearance of popcorn.-Evaluation: An acceptable descriptor.

posterior junction line, n. Radio!. A vertically oil-ented, linear or curvilinear opacity about 2 mm

wide, commonly projected on the tracheal airshadow and usuaNy slightly concave to the right.it is produced by the shadows of the right andleft pleurae in intimate contact between the aer-atod lungs. It represents the plane of contactbetween the lungs posterior to the esophagusand anterior to the spine; hence, in contrast tothe anterior junction line, it may extend bothabove and below the suprastemal notch and maybe seen above and/or below the azygos andaortic arches. -Synonyms: posterior mediastinalseptum, posterior mediastinal line. -Evaluation:A specific feature of radlologic anatomy. to bepreferred to the synonyms.

posterior tracheal stripe, n. Radio!. A verticallyoriented, linear opacity ranging in width from 2 to5 mm, extending from the thoracic inlet to thebifurcation ofthetrachea and visible only in lateralradiographs of the chest. It is situated betweenthe air shadows of the trachea and the right lungand is formed by the posterior tracheal wall andcontiguous mediastinal interstitial tissue. -Syn-onym: posterior tracheal band. -Evaluation: Aspecific feature of radiologic anatomy. Posteriortracheal stripe is preferred to posterior trachealband.

primary complex, n. 1. Pathol. The combination ofa focus of pneumonia produced by a primarymfection (e.g., tuberculosis or histoplasmosis)with granubomas in the dralnrng hilar or medias-tinal lymph nodes. 2. Radio!. a. The combinationof one or more irregular pulmonary parenchymal

opacities of variable extent and location assumedto represent consolidation with enlargement ofthe draining hilar or mediastinal lymph nodes; anappearance assumed to represent an active in-fection. b. The combination of a small, sharplydefined parenchymal opacity(often calcified) withcalcification of the &alning hilar or mediastinallymph nodes; an appearance usually regarded asevidence of an inactive process. -Synonyms:Rankecomplex. Ghon complex. Primary complexis to be preferred to Ranke complex, which isacceptable but rarely used, and Ghon complex,which represents an inappropriate use of theeponym and is unacceptable. -Evaluation: Auseful inferred conclusion.

profusion, n. Radio!. I. A qualitative expression ofthe number of small opacities per unit area orzone of lung. 2. In the ILO/1980 classification ofradiographs of the pneumoconioses. the quaIl-flora 0 through 3 subdIvide the profusion of smallrounded and small irregular opacities into fourmajor categories. These may be further subdi-vided to provide a 12 point scale: -/0,0/0,0/1;1/0,1/1,1/2;2/1,2/2, 2/3; 3/2, 3/3, 3/k.

pseudocavlty, n, -lee. Radio!. Any shadow corn-plex that has the appearance of a gas-containingspacewithin a zoneofconsolidation, a pulmonarymass, or a nodule when, in fact, no such spaceexists; hence: 1. A central lucency within a noduleor mass that is proved by computed tomographyor pathologic examination to represent lipid. 2.An apparently circumscribed lucency created bythe confluence of shadows of normal anatomicstructures, most commonly ribs and pulmonaryvessels, that does not, in fact, represent a cavity.-Synonyms: 2. composite shadow, spuriouscavity. -Evaluation: 1. An inferred conclusion,sometimes used as a descriptor. The term iswithout causative connotation. Its use is not rec-ommended.

pulmonary blood flow re�sthbution, n. 1. Physiol.Any departure from the normal distribution ofblood flow in the lungs, whether physiologic orpathologic. 2. RadiO!. Narrowing and reduction inthe number of visible pulmonary vascular shad-ows in one or more lung regions associated withcorresponding widening and increase in the num-bar of Visible pulmonary vascular shadows in the

516 FLEISCHNER SOCIETY GLOSSARY AJR:143, September 1984

remaining lung regions. -Evaluation: An inferredconclusion, often used as a descriptor and appro-priately based on radiographic evidence alone.

pulmonary edema, n. 1. Pathophysiol. The accu-mulation of fluid in the interstitial compartment ofthe lung with or without associated alveolar filling.Specifically, the accumulation of water, protein,and solutes (transudate) usually due to (1) �ri-creased pressure in the microvascular bed; (2)increased microvascular permeability; or (3) im-paired lymphatic drainage. Also, the accumula-tion of water, protein, solutes, and inflammatorycells(exudate)in response to inflammation of anytype (e.g., infection, hypersensitivity, trauma. orcirculating toxins). 2. Radio!. An inferred conclu-sion applicable to a pattern of opacity (oftenbilaterally symmetric and perihibar in distribution)believed to represent alveolar filling and/or inter-stitial thickening when associated findings and/or history suggest one of the processes enumer-ated above. ualifiers: I. Interstitial edema:pulmonary edema confined to the interstitial corn-partments of the lung; initially the bronchovas-cuber interstitial space and its continuum, subse-quently the alveolar wall interstitial space. Alveo-lar edema: pulmonary edema involving the alveolias well as the interstitial space. Synonyms: 2.Wet lung, boggy lung. moist lung. drowned lung.-Evaluation: An inferred conclusion often usedas a descriptor. A useful and acceptable termwhen used in an appropriate clinical setting. Thesynonymous terms are colloquialisms to beavoided.

pulmonary perfusion, n. 1. Physiol. The passageof blood through the vessels of the lung or a partthereof. 2. Radio!. Any radiologic evidence ofpulmonary blood flow in the physiologic sense. Itmay be explicit (in the case of pulmonary angiog-raphy) or inferred (in the case of conventionalradiography). -Synonym: pulmonary blood flow.-Evaluation: a physiologic conclusion that canproperly be based on, or inferred from, radiobogicevidence alone. A useful and recommended term.

Rradiographic contrast, n. Radio! phys. 1. The dif-

ference in optical density between two specifiedshadows (usually adjacent) in a processed radi-ograph. 2. The resultant of film contrast andsubject contrast. -Evaluation: A fundamentalconcept of radiologic physics, useful in a clinicalcontext as one determinant of radiographic qual-Ity.

radiographic quality, n. 1. Radio!. An expressionof the acceptability of a diagnostic radiograph tothe interpreter; a subjective evaluation. 2. Radio!phys. An expression of the correspondence be-tween the physical characteristics of a radiographand some predefined standards, usually with re-spect to contrast, resolution, and density; anobjective evaluation. -Synonym: film quality. -

Evaluation: A useful concept, but only in a loose,qualitative sense. The term defies precise quan-titative definition and is not in either sense anexpression of the diagnostic usefulness of a ra-diograph.

radlologic sign, n, -s. Radio!. A shadow or shadowcomplex said to be reliable evidence of a specificpathologic state, process, or relation. A list (in-complete) of specific signs, their reputed signifi-cance, and their reliability is as follows: brokenbough 5.: peripheral bronchial occlusion (highlyunreliable). camabote 5.: echinococcus cy5t (reli-abbe). continuous diaphragm s.: pneumomedias-tinum (usually reliable). crescent 5.: intracavitarymass; hydatid cyst, fungus ball, etc. (reliable cvi-dence of an intracavitary mass but not specificwith respect to cause). gloved finger s.: bron-

chiectasis (usually reliable). hibar bifurcation 5.:vascular vs. extravascubar hilar enlargement (urn-ited usefulness). hllum overlay 5.: cardiomegalyvs. antenormediastinal mass(limited usefulness).melting Ice s.: pulmonary infarction (limited use-fulness). moon 5.: see crescent a. 1-2-3 s.:pulmonary sarcoidosis (unreliable; misleading).rabbit ear s.: bronchioboalveolar cell carcinoma(unreliable). scimitar s.: partial anomalous pub-monary venous return (reliable). sIlhouette s.:presence and localization of intrathoracic lesion(reliable). tall 5.: see rabbit ear s. (unreliable).water lily 5.: see camabote s. (reliable). Wester-mark s.: pulmonary embolus(usually reliable). -

Evaluation: Signs are seldom as specific as theirauthors believe, and their meanings are oftenconfused through frequent misuse. Many are un-reliable(e.g., rabbit ear)or totally erroneous (e.g.,1-2-3 sign of sarcoidosis). With the exception ofa few generally recognized and usually reliablesigns (scimitar, silhouette, Westermark), the useof signs as descriptors is not recommended.Specific description of the individual finding ispreferred.

residual, n. Radio!. Any nonspecific opacity of un-certain cause believed to represent an inactiveprocess. -Synonym: scar. -Evaluation: An in-termed conclusion. The term is vague, grammati-cally incorrect (residuum is the noun), and shouldbe rejected in favor of more precise diagnosticstatements.-adj. Of or pertaining to a residue or remainder.

resolution, n. 1. Radio.! phys. a. A quantitativeexpression of the number of punctate or linearabsorbers that can be recorded as perceptiblydiscrete shadows per unit distance across a ra-diographic receptor; usually expressed in linepairs per millimeter. (Metallic wires are usuallyused as test objects for such measurements.) b.The characteristic of a radiographic receptor sys-tern that expresses its ability to record closelyapproximated absorbers as discrete shadows. c.The spatial frequency response of a radiographicsystem, usually expressed in terms of its modu-laden transfer function (MTF). d. A measure ofthe “fidelity of the imaging system. -Synonym:resolving power. -Evaluation: Resolving poweris technically the correct term, but by virtue ofbong usage, resolution is acceptable in this sense.2. Pathol/Radiol. The process by which a lesion,specifically aconsolidation, clears. It may becom-plete or partial. -Evaluation: An explicit diagnos-tic statement appropriately based on serial radi-ographs.

respiratory failure, n. Physic!. A pathologic stateresulting from impaired respiratory function andcharacterized by an arterial Po� below 60 mm Hgor an arterial Pco� above 49 mm Hg, in a subjectat rest at sea level. -Qualifiers: acute, chronic.-Synonym: pulmonary insufficiency. -Evalua-tion: A useful term in its clinical and physiologicusage that should never be used as a radiobogicdescriptor. It is preferred to pulmonary insuffi-ciency.

retbcular pattern, n, -s [usually in the singular].Radio!. A collection of innumerable small linearopacities that together produce an appearanceresembling a net. -Qualifiers: fine, medium,coarse. -Synonym: Small irregular opacities (inthe lLO/1980 classification of pneumoconioses).-Evaluation: A recommended descriptor. It hasno pathologic connotation and should not beused as a synonym for interstitial disease of thelung. The synonymous term smallirregular opec-ities should be restricted to the radiographic char-acterization of pneumoconiosis.

reticubonodular pattern. n, -s [usually in singular].Radio!. A collection of innumerable small, linearand micronodularopacities that together producea composite appearance resembling a net with

small superimposed nodules. In common usage,the reticular and nodular elements are dimen-sionally of similar magnitude. -Qualifiers: fine,medium, coarse. -Evaluation: An acceptableradiobogic descriptor without specific pathologicwnplications.

righttracheal stripe. n. Radio!. A vertically orientedlinear opacity 2-3 mm wide that extends fromthe thoracic inlet to the right tracheobronchialangle in the frontal radiograph. It is situated be-tween the air shadow of the trachea and the rightlung and is formed by the right tracheal wall andcontiguous mediastinal interstitial tissue and ad-jacent pleura. -Synonyms: right paratrachealstripe or band. -Evaluation: A specific feature ofradiographic anatomy.

S

segment, n, -s. Anat/Radiol. One of the Principalanatomic subdivisions of the lobes of the lung(usually 10 on the right and 9 on the left); a lobarsubdivision served by a major branch of the bobarbronchus. -Qualifier: bronchopulmonary.

segmental, adj. Mat/Radio!. Of or pertaining to asegment.

septal line, n, -s [usually in the plural]. Radio!. Ageneric term for fine, linear opacities of varieddistribution produced by the interstitium betweenpulmonary lobules when the interstitium is thick-ened by fluid, dust deposition, cellular material,etc. -Synonyms: Kerley lines (q.v.), lymphaticlines; of. interlobar septum. Septa! lines is thepreferred term; Kerley lines is acceptable, partic-ularly when one seeks to identity a particular typeof septal line (e.g., Kerley B lines). Lymphaticlines is anatomically an inaccurate term andshould not be used in this context. -Evaluation:A specific feature of pathologic radiobogic anat-omy. often inferred. A recommended term.

shadow, n, -s. Radio!. 1. In clinical radiography,any perceptible discontinuity in film blackeningascribable to the attenuation of the x-ray beamby a specific anatomic absorber or lesion on orwithin the body of the patient. An opacity orbucency. 2. A similar discontinuity in any otherdiagnostic visual representation of the remnantenergy in an x-ray beam after its passage throughthe body of the patient (e.g.. a fluoroscopic im-age, a CAT display, etc). -Qualifiers: The termshould always be qualified as precisely as possi-ble with respect to size, contour, location, opacity(lucency), etc. -Evaluation: A useful and rec-ommended descriptorto be used only when morespecific identifiCatiOn is not possible.

shaggy heart, n. Radio!. A heart whose border ispartially effaced by multiple small, irregularly dis-tributed opacities produced by any of severalpathologic processes affecting the paracardiacparts of the lungs and/or pleura. -Evaluation:This term is an imprecise radiologic descriptor, tobe used with caution.

sIlhouette sign, n. Radio!. 1. The effacement of ananatomic soft-tissue border by consolidation ofthe adjacent lung or accumulation of fluid in thecontiguous pleural space. 2. A sign of the con-formity and, hence, of the probable adjacency ofa pathologic opacity to a known structure; usefulin detecting and localizing a consolidation alongthe axisofthe x-ray beam. -Evaluation: A widelyaccepted and useful radiologic descriptor. Itshould be noted that the finding, in fact, involvesthe loss of a silhouette.

small irregular opacity, n, -lee [usually used in theplural]. Radio!. 1. Small pulmonary opacities thatdefy classification in terms of simple geometricdescriptors, that are often poorly defined, andthat in large numbers produce an appearance

AJA:143, September1984 FLEISCHNER SOCIETY GLOSSARY 517

resembling a net. 2. In the ILO/1980 classificationof radiographs of the pneumoconioses, the qual-iflers s, t, and u subdivide such opacities intothree categories on the basis of their greatestthickness: s, up to 1.5 mm; t, I .5-3 mm; and u,3-10 mm. -Synonym: reticular pattern. -Eval-uation: A term to be used specifically to describeradiographic manifestations of the pneumoco-nioses. Reticular pattern is preferred when refer-ring to nonpneumoconiotic disease.

small rounded opacity, n, -lee [usually used in theplural]. Radio!. 1. Innumerable small pulmonarynodules ranging in diameter from bare visibllityup to 10 mm. 2. In the lLO/1980 classification ofradiographs of the pneumoconioses. the quail-flersp, q, and r subdivide the predominant opac-Ities into three diameter ranges: p. up to 1 .5 mm;q, 1 .5-3 mm; and r, 3-1 0 mm. -Synonym:nodular pattern. -Evaluation: A term to be usedspecifically to describe radiographic manifesto-tions of the pneumoconioses. Nodular pattern ispreferred when referring to nonpneumoconioticdisease.

stripe, n, -S. Radio!. An extended longitudinal, corn-posite opacity 2-5 mm wide; cf. line, bandshadow, linear opacity. -Evaluation: An ac-ceptable descriptor when used with reference toradiographic shadows within the mediastinum.

subject contrast, n. Radio! phys. 1. Quantitative:The ratio of the intensities of the remnant radia-ben, including scatter, emerging from two spool-fled absorbers in the path of an x-ray beam. 2.Qualitative: The difference in attenuation of dif-ferent absorbers resulting from differences intheir physical densities, effective atomic num-bars, and path lengths. -Evaluation: A funda-mental concept of radiologic physics.

subse9ment, n, -s. Anat/Radiol. A unit of pulmo-nary tissue that is supplied by a bronchus oflesser order than a segmental bronchus, butwhich is larger than a lobule.

subsegmental, adj. 1. Anat/Radiol. Of or pertainingto a subsegment. 2. Radio!. Of or pertaining toany pulmonary shadow, smaller than a segmentand larger than a lobule, presumed to representa subsegment in the anatomic sense. -Evalua-tion: An acceptable radiologic descriptor.

Ttension, adj. 1. The state of being stretched or

strained. 2. Physiol/Med. A state characterizedby cardiorespiratory functional impairmentcaused by pneumo- or hydrothorax. 3. Radio!.The accumulation of gas or fluid in a pleural spacein an amount sufficient to cause compression ofthe ipsilateral lung, markedly enlarge the herni-thorax, depress the hemidiaphragm, and displacethe medistinum to the opposite side; applicableonly in the presence of clinical cardiorespiratoryembarrassment. -Evaluation: An inferred con-clusion to be used only as specified in the defi-nition. In fact, tension in relation to pneumothoraxexists only during the expiratory phase of therespiratory cycle, since pleural pressure on inspi-ration is usually subatmospheric. The wordshould not be used in the term tension cyst, whichdoes not satisfy the criteria cited above.

tramline shadow, n, -s [usually in plural]. Radio!.Parallel or slightly convergent linear opacities thatsuggest the planar projections of tubular struc-tures and that correspond in location and orion-tation to elements of the brOnchial tree. They aregenerally assumed to represent thickened bron-chial walls. (Such shadows are of possible path-obogic significance only when they occur outsidethe limits of the hilar shadows where bronchialwalls may be seen in the normaL) -Synonyms:thickened bronchial wails, tubular shadows(q.v.). -Evaluation: A radiologic descriptor, theuse of which is not recommended. Linear opaci-ties properly qualified with respect to size, loca-tion, and Orientation �5 tO be preferred.

trough filter, n. 1. Radio! phys. Any x-ray filtertraversed by a longitudinal zone of diminishedthickness. 2. Radio!. An x-ray filter designed toattenuate preferentially those parts ofthe primarybeam that will traverse the lungs of the patient inthe exposure of a frontal chest radiograph.

tubular shadow, n, -s. Radio!. 1. Paired, parallel orslightly convergent linear opacities presumed torepresent the walls of a tubular structure or do-vice (e.g., a bronchus, vessel. or chest tube, seenin profile). 2. An approximately circular opacitypresumed to represent the wall of a tubular struc-ture or device seen en face. -Qualifiers: Bron-chial walls are usually not identifiable radiograph-ically unless thickened; arterial walls, unless cal-cified. These qualifiers are, therefore, almost es-sential to their description. -Synonyms: tramlineshadow, thickened bronchial wall. -Evaluation:A common radiobogic descriptor, but dearly amisnomer to be avoided. Shadow of a tubularstructure is acceptable if the anatornic signifi-cance of a shadow is truly obscure; otherwise,thickened bronchial wail or Calcified arterial wailis to be preferred.

turner. n, -s. 1. A swelling or morbid enlargement.2. Pathol anat/Radio!. Literally, a mass. -.Syn-onym: mass. -Evaluation: A useful descriptor.Mass is preferred. The term does not differentiatebetween a neoplastic and a nonneoplastic mass;its use as a synonym for neoplasm is to becondemned.

VValsalva maneuver, n. Physiol. Forced expiration

against a closed glottis, usually but not neces-sarily from a position of total lung capacity. Amaneuver used to produce transient increase inintrathoracic pressure.

vascular prominence, n. Radio!. Real or apparentincrease in the caliber and/or number of pubmo-nary vessels beyond the expected range, which,in view of the wide range of normal, does notnecessarily imply a pathologic departure fromnormal. ynonyms: increased vascularity, vas-cular engorgement, pulmonary hyperemia, put-monary plethora, pulmonary pleonemia. Theseterms all represent inferred conclusions and arenot, therefore, strictly synonymous with vascularprominence. Each is applicable only in specifiedcircumstances and each must be used with care.-Evaluation: The term vascular prominence is

an acceptable radiologic descriptor.vasoconstrictlon, n. 1. Physio!. The narrowing of a

muscular blood vessel by contraction of its mus-ole layer. 2. Radio!. Local or general reduction inthe caliber of visible pulmonary vessels that ispresumed to result from decreased blood flowproduced by contraction of muscular pulmonaryarteries. -Qualifiers: hypoxic, reflex. -Anto-nym: vasodilation. -Evaluation: In the interpro-tation of conventional radiographs, an inferredconclusion appropriately based on radiographicsigns that are usually reliable. In the interpretationof angiograms, an explicit radiographic conclu-sion. The term is not synonymous with oligernia.Oligerniais a sign ofvasoconstriction, a functionaland potentially reversible process; it also appliesto wreversible vessel narrowing. as in emphy-some.

vasodllatatbon, n. 1. Physiol. The widening of thelumen of a muscular blood vessel by relaxationof its muscle layer. 2. Radio!. The local or generalincrease in the width ofvisibbe pulmonary vesselsresulting from increased pulmonary blood flow-Synonym: vasodilation. -Evaluation: In theinterpretation of conventional radiographs, an in-ferred conclusion to be expressed with caution,since apparent widening of pulmonary vascularshadows may. in fact, be due to perivascularedema, neoplasm, etc. In the interpretation ofangiograms, an explicit conclusion.

ventilate, v. Physiol. I. To circulate air into and outof any closed space. 2. Specifically, to introducefresh air and expel stale air from the lungs byphysiologic or mechanical means. 3. To providewith a patubous opernng for the circulation of air.-Qualifiers: hyper-; hypo-.

ventilated, adj. 1. Having had fresh air admittedand stale air expelled by physiologic or mechan-ical means. -Qualifiers: hyper-; hype-.

ventilation, n. Physio!/Radio!. 1. The dynamic actsof inhaling fresh air and exhaling stale air. 2. Themovement of air into and out of the lungs. 3.Inspiration and expiration. -Qualifiers: hyper-(preferred) or over- ; hype. (preferred) or under-.-Synonyms: breathing. respiration; cf. aeration,inflation. 4. Physic!. Oxygenation of the blood,specifically in the act ofrespiration. -Evaluation:A useful term if properly used. The term alwayswnplies a blphasic dynamic process of admissionand expulsion; hence, cannot be assessed froma single static image. Not to be used synony-rnously with aeration and inflation.

xx-ray quality, n. Radio! phys. The effective energy

or spectral distribution of an x-ray beam. 1. Usu-ally expressed in terms of half-value layer (HVL)in mm of aluminum. 2. Often implied, but notexplicitly defined, by a statement of the peakvoltage applied to the x-ray tube. -Synonym: x-ray beam quality. -Evaluation: A fundamentalphysical measurement useful clinically in spool-lying and comparing radiographic systems andtechniques. The practice of expressing x-rayquality in terms of beam �hardness is to beavoided.