Thoracic Imaging

Thoracic ImagingHENDRA . MD 1Thoracic ImagingChest x-rayComputerised tomographyUltrasoundMagnetic resonance imaging New advances2MRI not widely used but can show malignancy especiallyWe will look at actual films in the tutorials/practicalsBackground Chest X-rayMost common radiological investigation 40% of all investigations

Standard component of a pulmonary examination

Systematic review is vital in interpretation of chest x-rays

3Up to 40% off all radiological investigations are chest x-rays60% are carried out in the ICU, Sensitivity; 50% of critically ill patients in Icu will have abnormal chest x-rayA systematic review is vital when interpretating x-rays however what order is not critical and you will come across varying ordersLimitations of a chest x-ray2 dimensional image of a 3 dimensional structureX-ray findings may lag behind other clinical featuresNormal x-ray does not rule out pathologyDependent on good quality image4A chest x-ray forms a piece in the pulmonary examination, should refer to previous x-rays if available and if possible put in context of the other pulmonary findingsChest x-ray views/typesPosteroanterior - PAAnteroposterior - APLateralDecubitus

ViewsPAStandard, radiology deptX-rays posterior to anterior Standing position

6PAStandard investigation carried out in the x-ray deptCassette anterior to chest, x-rays shot post-ant from 2 metres away, shoulders abducted to remove scapulaCarried out in standing therefore better inspiration

Normal PALung Anatomy(1) aortic arch (2) pulmonary trunk(3) left atrial appendage(4) left ventricle(5) right atrium(6) superior vena cava (7 & 8) diaphragm(9) transverse fissure

9Transverse fissure 6th rib laterallyDoes not estend beyond pulm artery mediallyVisible in 50%ViewsAPCassette placed behind patientX-rays anterior to posteriorSitting in chair, semi-erect in bed, supineAP marked on filmHeart enlarged, poorer inspiration

10APCassette placed behind the patient, portable machinePatient could be sitting in a chair, semi erect in bed, supine in bed. NOTE the patient position will affect the CXRMarked AP on filmHeart enlarged often poorer expansion

Normal APViewsLateralLocalises, shows posterior to heartSide of interest placed against film

DecubitusPA on sideSmall pleural effusions

12LateralHelps to localise diseaseSide of interest placed against filmIdentifies posterior to the heart and costophrenic recesses

DecubitusPA with patient on sideSmall pleural effusions

Norm lateralvertebraeHeartLung Anatomy

(1) oblique fissure(2) transverse fissure(3) retrocardiac space(4) retrosternal space14Oblique fissure from t4 posteriorlyPropeller shapedDifferentiation between sides- left is more vertical, has more posterior junction with the diaphragm= does not intersect transverse fissure

Left diaphragm is lower and possesses stomach bubble by 2.5cm in 94% populationBASICSAir shows as black solid structures white

Too whiteToo blackToo largeIn the wrong place (Corral et al 1997)15Chest x-ray viewing guideCorrect CXRNameDate of birthDate Left and right, marker/stomach16How to viewCheck patient and x-ray detailsLeft or right, markers placed on by radiographer, stomach on left. Heart not always on left

Normal PAStomachPatient PositionPA, AP, lateral or decubitus viewRotation Sternal end clavicles equal from vertebral bodyIf AP what position 18QualityIF AP will have poorer inspiration and larger heart If patient supine will not see pleural effusions very wellExposureHow dark or light a film is Should see vertebral bodies through heart19AP will show KV/MASSoft TissuesBreast shadowsPiercingAir in tissuesTissue folds in obeseMedical equipment20Breast shadows mastectomy!Medical equipment, lines (CVP, ICD), endotracheal tube, NG tube, metal implants, pacemakers

Breast shadows

Surgical emphysema

surgical emphysema

PacemakerHeart valve

ICDECGETTBony StructuresRibsScapulaeClaviclesVertebrae26Ribs fractures, osteoporosis. Ribs even ScoliosisScapulae need to be identified so do not confuse when looking at lung fields

#Clavicle

#ribsTracheaDeviatedCarinaArtificial airway29Trachea can be pushed or pulledAir filled sacs keep trachea in middle

ETT#RibsICDMediastinumDeviatedHilar shadowsAortic arch31Hilar shadows, pulmonary vasculature and lymph nodes, right side is slightly further out and the left is usually higher by 2 cm, with COPD will get upper lobe diversionAortic arch may be calcified

Mediastinum - HeartSizeNo larger than half width of chestPositionTwo thirds on the leftBordersClear32HeartSize, is usually half the width of the chest, is increased with AP picture, and in cardiac disease. Will look smaller if lungs hyperinflated and larger if very poor inspirationPositioned two thirds to the left unless have dextrocardia

DiaphragmShapeHeight: right 6rib ant, left 7 antCardiophrenic angleCostophrenic angle

33ShapeDomed, flattened with hyperinflation more domed with poor inspiration or paralysis, gas in stomachHeightRight 6 rib ant, left 7 rib anter in 95% of populationLeft lower because of weigh of heartBear in mind structures below as stomach can push up occasionally liver can push up, ascites will push upAnglesClear if cardiophrenic poor collapse, if costophrenic blurred pleural effusion

Lung FieldsBlack with lung markingsOther opacity indicated pathologyFissuresZonesAir bronchogramsConsolidation34Lung markings of vessels, absent if a PneumothoraxPulmonary oedema - bilateralFissuresRight horizontal, present in 80% of PAsThird thoracic spine, goes down and anteriorlyFluid present? Moved?Oblique on lateral onlyZonesUpper, above 2nd rib antMiddle, 2-4 rib antLower, below forth ribOpacity increased with fluid, consolidation, malignancy

normalRight upper lobe collapse

Right Lower lobe collapse

Pneumothorax

Pneumothorax

Consolidation

Pleural effusion

Pleural effusion

Right pneumonia

Air bronchogram

EmphysemaOther imaging Computerised tomographyTransverse images, cross sectionLocalises massesHigh radiation dose46Other imaging contUltrasoundUseful for pleural effusionsGood images of heart and valves47Loculated pleural effusionOther imaging contMRIMalignancyVascularCongenital abnormalitiesTuberculosis48May be useful if other imaging not possibleNew advancesPatient archive communication systemFilm free radiologyComputer useImage enhancement49PACSImages stored and generated on computer, allows multiple viewings at once, images can be enhanced, reduces storage and film losses. Useful for teaching as can view radiological reports