Imaging of Large Airways Disorders

dr. Yanto Budiman, Sp.Rad, M. Kes

Aprilia Wanda

Lestari Anjani Dewi

Michael

Gita Putri Anjani

Abstract

• Objective :• CT thin sections and techniques 2D and 3D increase ability to detect

airways diseases• CT protocols evaluation of dynamic airway disfunction

• Conclusion :• Disease of large airways common radiologist must be familiar with

appearances, DD, and clinical implication

Background

• Large airways : Trachea, Lobar, and Segmental bronchi (until 2-3mm)• Recent CT 2D and 3D improve ability to identify diseases or lesions• Dedicated CT protocols allow the evaluation of dynamic airway

dysfunction :• End-inspiratory CT paired with either dynamic expiratory CT during forceful

exhalation or static end-expiratory CT• Cine CT during coughing

• Indication of imaging of the large airways : pulmonary function test show a discrepancy with clinical presentation• It is important to be familiar with the appearances, DD and clinical

implication of the diseases

Congenital Abnormalities

• Tracheal Bronchus• Accessory Cardiac Bronchus• Bronchial Atresia• Tracheoesophageal Fistula• Tracheal Stenosis

Tracheal Bronchus• Anatomical variant accessory bronchus

originates from supracarinal trachea• 2 Type : supranumerary, and displaced• Pig Bronchus when the entire upper lobe

(usually right side) is supplied by this bronchus• Incidence 0,1-2%• Asymptomatic but impaired drainage recurrent

pneumonia• ETT AtelectasisTracheal bronchus. Available from :

http://radiopaedia.org/images/5967671

Tracheal Bronchus (2)

Chest radiograph of a 20-year-old man showing a right tracheal bronchus (arrow) and paratracheal mass with the trachea shifted to the left.Available from : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2659830/

Accessory Cardiac Bronchus• Rare variant of tracheobronchial tree , arising from

medial aspect of the bronchus intermedius or less commonly the right mainstream bronchus• Incidence 0,09%-0,5%, predilection males• This bronchus progresses conically in an inferior direction

toward the pericardium• Most end blindly, some develop into a series of small

bronchioles ending in vestigial bronchiolar parenchyma or ventilated lobules• Asymptomatic, abnormal drainage recurrent

pneumonia, hemoptysis

Bronchial Atresia• Congenital obliteration of bronchial segment,

most frequently the left upper lobe with normal development of airways proximal and distal to the lesions, • Usually asymptomatic, if symptomatic

shortness of breath, cough or rarely infection• Airways distal of the obliteration characteristics

with :• Dilated• Fill with mucus• Bronchocele

• Often accompanied with : bronchogenic cysts, and anomalous branching of the bronchial tree and vascular structures• Finding in chest radiography and CT:

• Central V or Y shaped tubular opacity (finger glove appearance) surrounded by hyperlucency to air trapping and hypoperfusions

Tracheoesophageal Fistula• Abnormal connection between the trachea

and the esophagus• Most occur with esophageal atresia and

are diagnosed in neonates• Feeding difficulty, respiratory compromise

due to repeated aspiration• TEF without esophageal atresia “H-Type

fistulas” and may occasionally be diagnosed later in life• Most TEF in adults tumor, infections or

trauma• Congenital TEF have a high association

with other congenital anomalies, including cardiovascular, genitourinary and GIT malformation• Chest radiography may be suspected if

there is an unusual amount of intestinal distention from air leaking into GIT

Tracheoesophageal Atresia (2)Esophageal atresia is closely related tracheoesophageal atresia can be divided into:type A: isolated esophageal atresia : 8%type B: proximal fistula with distal atresia: 1%type C: proximal atresia with distal fistula: 85%type D: double fistula with intervening atresia: 1%type E: isolated fistula (H-type): 4%

• Red arrow points to end of orogastric tube which is blocked from entering the distal esophagusby the patient's esophageal atresia. Note the lack of gas in the abdomenindicating a fistulous tract does not connect the trachea to the distal esophagus

Tracheal Stenosis• Congenital stenosis refers to narrowing of the

tracheal lumen without airway wall thickening• Most frequently complete or near-complete

tracheal rings• Severe involving long airway segment

symptomatic early during infancy• Mild asymptomatic and an incidental finding

in adults• Imaging diffuse, segmental or funnellike

progressive airway stenosis without wall thickening• Long segmental stenosis due to complete

tracheal rings may be associated with a left pulmonary artery sling• High mortality, treated with bronchoscopic

dilatation and stent placement, surgical resection of the involved segment or tracheoplasty

Iatrogenic and Traumatic Abnormalities

Post intubation stenosis

Tracheal stenosis : - Congenital- acquiredMost common ETT, tracheostomyRo : focal luminal narrowing CT : circumferential hour glass apperance

Congenital tracheal stenosis

Post intubation stenosis

Traumatic injury

most frequently : brochii 2,5 cm of carinaRo: pneumomediastinum and pneumothoraxCT : focal defect or deformity at the site of airway injury or absence of the airway injury.

Traumatic injury

Foreign body aspiration

Foreign body can be nonopaque or opaque .Common nonopaque food particle.

Ro : cannot be detectedCT : showing and localizing both opaque and nonopaqueDynamic CT sequence :atelectasis and air trapping

Foreign Body

Extrinsic compression

compressed by enlargement of the surrounding structure.Congenital vascular anomalies or fibrosing mediastinitisRo and CT : luminal narrowingDynamic CT : air trapping and acquired focal airway collaps.

External compression

Chronic Inflammatory and Infiltrative Disease

Tracheobronchomalacia

Refers to excessive airway collapse during expiration-Weakening the airway cartilage-Nonweakening the airway cartilage EDAC

Traditional diagnosis : bronchoscopicDynamic CT : airway collaps exceeding 70% with forced expiration

2 classic patern of collaps :-Cresentic : frown sign-Circumferential : evenly distributed

Air collaps : accompanied by air trapping

Can make severe respiratory distress

Treatment : CPAP, stent placement, tracheoplasty

Tracheobronchomalacia

Amyloidosis

Characteristic by extracelluler accumulation of abnormal proteinaceous, insoluble fibrin

Underlying bronchial architecture

Amyloidosis : -Systemic : common-Localized : rare

Amyloidosis

Best detected : CTCT : -Solitary nodule/multiple nodule protuding intu airway lumen-Mural calcification

Treatment : Bronchoscopic techniques : debridement, laser ablation, ballon dilatation, and stent placementLocal amyloidosis : radiation/chemotherapy

Tracheobronchial amyloidosis

Sarcoidosis

Idiopathic multisystemic granulomatous disease that typically involves thoracic lymph nodes and the lung parenchyma.

Involve :

-Rare : trachea and main bronchi

-Common : lobar and segmental bronchi

Sarcoidosis stage : -Early stage-Late stage

Ro : severe narrowing of trachea and main bronchiiCT : -subtle airway lesions such as nodular, or smooth airway wall thickening and narrowing-Air narrowing result : lymph nodes compressing.-Traction bronchiectasis : severity of fibrosis.-Monitoring disease progression

Sarcoidosis

Granulomatosis with Polyangiitis

• Antineutrophil cytoplasmic antibody-associated vasculitis.

• Affects small and medium-sized vessels.

• Manifestation: tracheobronchial tree involvement.

• Airway wall thickening, fixed or reversible stenosis.

• Iregular calcifications of the tracheal cartilage rings.

• Chest Radiography: smooth stenosis of the airways and pulmonary opacities.

• CT: smooth or nodular thickening of the tracheobronchial wall -> single or multiple stenosis

Relapsing Polychondritis

• Rare autoimmune disorder causing recurrent inflammation and subsequent destruction of cartilage in the ear, joints, airways and nose.

• Inflammation and destruction -> loss of supportive function -> excessive collapse of the airways during expiration.

• Stenosis and mural thickening.• CT: diffuse smooth thickening of the

tracheobronchial wall, excessive collapsibility associated with air trapping.

• Calcifications, stenosis and obstructive bronchiectasis.

• Poor prognosis.

Tracheobronchomegaly

• Mounier-Kuhn syndrome• Congenital presidposition combined with

acquired factors such as infections and chronic irritation from smoking.

• Dilatation of the trachea and main bronchi results from atrophy of smooth muscle and elastic tissue.

• Radiography: tracheobronchomegaly• CT: increased diameter and extent of airway

dilatation, multiple small diverticula and bronchiectasis.

• Women: coronal -> 21mm, sagittal -> 23mm.• Men: coronal -> 25mm, sagittal -> 27mm.

Tracheobronchopathia Osteochondroplastica

• Rare idiopathic condition, causing thickening of the tracheal rings.

• Affects trachea and cartilaginous components.

• Chest radiography: normal, tracheal scalloping or irregular asymmetric airway stenosis.

• CT: thickened cartilage rings with irregular calcifications and multiple nodules.

Bronchial Anthracofibrosis• Focal luminal narrowing of the bronchi

with darkened bronchial mucosa in patients without exposure to coal dust or cigarette smoking.

• Causes: tuberculosis, chronic exposure to biomass smoke.

• Nonspecific symptoms: cough, increased sputum production, dyspnea and recurrent infection.

• Chest radiography: consolidations or atelectasis.

• CT: thickening of the bronchial walls and peribronchial soft tissues.

• Lymph nodes often enlarged and may be calcified.

• Most common in lung distal.• Refer to: bronchogenic carcinoma and

endobronchial tuberculosis.

Bronchilithiasis

• Calcified material within the bronchial lumen.

• Calcified lymph node, typically caused by necrotizing granulomatous lymphangitis from histoplamosis or tuberculosis.

• The disappearance of or a change in the position of previously seen calcified opacity on chest radiography suggests broncholithiasis.

• CT: more sensitive.

Infection

• Inflammatory response focal or diffuse airway wall thickening and occasionally in luminal narrowing

Viral Infection

• Common: viral croup• Mucosal swelling seal like barking cough, stridor, hoarseness• Chest radiography indication: clinically uncertain steeple sign

without epiglotis involvement

Bacterial infection

• Bacterial tracheitis̶O More severe: membranous tracheal secretion̶O Lower respiration tract involvement: crackles, wheezing, pneumonia̶O Chest radiograph: narrowing upper trachea (irregular) + linear oppacities

within the tracheal lumen

• Endobronchial tuberculosis• Most common: distal trachea and proximal bronchi• Chest radiography: luminal narrowing or atelectasis, wall

thickening• CT: active and fibrotic stages, lymphadenopathy,

bronchiectasis, parenchymal inflammatory changes, severe stenosis (bronchoscopic dilatation and stenting)

• Rhinoscleroma (Klebsiella rhinoscleromatis)• Chronic nasal obstruction, rhinorrhea, epistaxis, absence of

the uvula, hebra nose• Dyspnea and stridor airway lesions (granulomatous

nodules, dense fibrotic stenosis)• Chest radiography: nodular irregularities/diffuse narrowing

of the large airways• CT: irregular, nodular, concentric luminal narrowing, wall

thickening of soft tissue without calcification. Sometimes mucosa shows crypt or sinuslike lesions

Fungal Infection

• Aspergillus, coccidioides, candida, cryptococcus, histoplasma• Underlying immune system condition

• Aspergillus:• Allergic bronchopulmonary: ↑ mucus production, ↓ ciliary

function mucoid impaction, mucosal invasion (-)• Chest radiography: -• CT: intraluminal nodules or masses of soft tissue, wall

thickening, stenosis, and occasionaly intramural air, bronchiectasis, lymphadenopathy, fingerlike opacities of soft tissue• Definite diagnosis: bronchoscopy

Neoplasms

Benign Neoplasms• <10% of airway neoplasms• Hamartoma• Tracheobronchial papillomatosis (human

papillomavirus): • Cavitated nodule• laryngx trachea, bronchi, lung

• Other: leiomyomas, lipomas, chondromas, neurogenic tumors

Malignant Neoplasms

• >2 cm flat or polypoid lesions with lobulated or irregular border• Most common: direct invasion• Less common: metastase• Bronchi: bronchial squamous cell carcinoma, small cell carcinoma,

carcinoid tumor

• Chest radiography: focal luminal narrowing from a soft tissue opacity or sigs of airway obstruction (atelectasis and recurrent pneumonia)• CT: intraluminal mass of soft tissue, may invade

surrounding structures• Hamartoma: fat and cartilaginous tissue within a lesion• Lipoma and liposarcoma: fat containing lesions• Carcinoid tumor: calcification and marked homogenous

contrast enhancement

• Definitive diagnosis: biopsy

Conclusion

• Evaluation of large airways: lumen, wall structure, wall thickness, lung parenchyma, and surrounding tissues• Distint pattern of dimensional and structural