CXR Interpretation

Views

PA: Preferred viewLat: Helps delineate and localize masses, lesions or consolidation – esp if they are obscured by heart and diaphragmÂP: Magnifies heart and mediastinum

Associated with rotational artefactExpiratory: helpful for small pneumothroax / gas trapping with FB

L image, L lung: oblique fissure, as shownR image, R lung: horizontal and oblique fissures, as shown

eg.

Reading a CXR

Patient and CXR dataTracheaLungsPulmonary vesselsHila: mass, LNHeartMediastinal contour: width, massPleura: effusion, thickening, calcificationBones: lesions or fractures

Soft tissues: don’t miss mastectomyTubes

Interpretation

Name and DOBDate of radiographProjectionPostureAdequacy of exposure – easily visible mid-thoracic IV spacesDegree of inspiration – diaphragm at levels of 8th -11th ribs posteriorly

5th - 6th ribs anteriorlyDegree of rotation – central spinous processes of thoracic vertebrae, equidistant from

medial ends of clavicles

Trachea – central; slight deviation to R as crosses aortic archPushed away: large pleural effusion

large/tension pneumothoraxaortic aneurysmmediastinal mass

Pulled towards: collapse Consolidation

pul fibrosis

lobectomy, pneumonectomy

Superior mediastinum – width <8cm on PAWide mediastinum: AP view

unfolded aortic arch, thoracic AA, aortic rupture mediastinal lymphadenopathy

retrosternal thyroid, thymoma paravertebral mass

oesophageal dilationMediastinal emphysema: penetrating wound

oesophageal/tracheal perforation, pneumomediastinum (asthma, whooping cough)

Hila – at T6-7 level; made of pul arteries and veins; L hilum 2cm higher and square shaped; R hilum V shaped

Hilar enlargement: hilar lymphadenoapthy (eg. sarcoidosis, infection) Hilar malignancy (eg. SCC) Vascular disease (eg. pul HTN)

Heart – 1/3 to R of thoracic spinous processesR heart border = RA

Poor distinction = consolidation of RMLL heart border = LV

Poor distinction = lingular consolidationCTR: should be <50%

Increased = AP film LVD, CCF, pericardial effusion

Diaphragm – R higher than L by 1-3cmLoss of outline = fluid, consolidation or collapseFlat diaphragm = COPDGas under diaphragm = rupture of hollow viscus

Post-laparoscopy

Lung outlines – look for pneumothorax, bullae, collapse, consolidation, effusions, masses, pleural changes; on lateral view lung lucency should increase towards diaphragm

Increased lucency towards diaphragm = COPD, pneumothoraxDecreased lucency towards diaphragm = alveolar / interstitial fluid, effusion, Consolidation

Neonatal CXRHeart 60-65% chest widthBronchial branching may give sense of air bronchogramsThymus (involution occurs age 6yrs; is anterior on lateral)

Pathology

Pul nodules = neoplasia (mets, 1Y lung tumour, adenoma, lymphangitis carcinomatosa)

Infection (military TB, varicella pneumonia, fibrotic lung disease, histoplasmosis)Vascular (AVM, haemartoma, PE)Cavitating nodular lung disease

Benign: unchanged for two years is almost certainly benigncompletely calcified or central or stippled calciumsolitary

Suspicious: nodules with irregular calcifications or those that are off center Multiple nodules

DD: granuloma, Ca, mets, round pneumonia, abscess, round atelectasis, hamartoma, sequestion, AVM, pleural plaques, skin lesions

Atelectasis: collapse or incomplete expansion of the lung or part of the lung linear increased density, often assoc with volume loss; may be compensatory hyperinflation of adjacent lobes, or hilar elevation / depression; segmental and subsegmental collapse linear, curvilinear and wedge-shaped opacities.

Causes: Endobronchial lesions: mucus plug, tumour Extrinsic compression – LN’s Peripheral compression – pleural effusion Cicatricial – scarring, TB, post-radiation

LUL collapse: loss of L upper cardiac border; LLL expands to fill space and L main bronchus more horizontal

LLL collapse, then partial resolution: loss of L hemidiaphragm and descending aorta

RUL collapse

RML collapse – note loss of R heart border; on lateral the two fissures start to approximate, cause wedge opacity pointing to hilum

RLL collapse – note persistence of R heart border; loss of R hemidiaphragm and triangular density posteromedially

Silhouette Sign – silhouette of heart borders, a’ing and d’ing aorta, aortic knuckle and hemidiaphragms should be clearly visible; obliteration of any of these borders suggests pathologyNote, pathology in posterior pleural cavity and lower mediastinum cause overlap but not obliteration of heart border

Ascending aortia and upper R heart border = RULR heart border = RMLUpper L heart border = LUL, anteriorAortic knuckle = LUL, apical portionL hear border = lingualAnterior hemidiaphragms = lower lobes, anterior

Air Bronchogram: tubular outline of an airway made visible by filling of the surrounding alveoli by fluid or inflammatory exudates

lung consolidationpulmonary edemanonobstructive pulmonary atelectasissevere interstitial diseaseneoplasmnormal expiration.

CCF: upper lobe diversionKerly B lines: horizontal, 2cm long; in lower zones; thickened oedematous interlobular septa; caused by pul oedema, lymphangitis carcinomatosa, lymphoma, viral and mycoplasmal pneumonia, interstitial pul fibrosis, pneumoconiosis, sarcoidosisPeribronchial cuffingBat wing shadowingPatchy shadowing with air bronchogramsCardiomegaly

Consolidation: fluid (inflammatory) Cells (cancer) Protein (alveolar proteinosis)

Blood (pul haemorrhage – Goodpastures, high altitude, bleeding disorders, mitral stenosis)

Pneumonia: airspace opacity / lobar consolidation / interstitial opacitiesVolume loss NOT seenLobar: usually pneumococcal; entire lobe; air bronchograms seenLobular: often staph; multifocal, patchyInterstitial: viral/mycoplasma; air bronchogram not seenAspirationDiffuse pulmonary infections: community acquired, nosocomial, Immunocompromised

Atelecatasis vs PneumoniaAtelectasis PneumoniaVolume loss Normal / increased volumeIpsilateral shift No shift, or contralateral shiftLinear, wedge-shaped Consolidation, air space processApex at hilum Not centred at hilumAir bronchograms can occur Air bronchograms can occur

TB ConsolidationAdenopathyPleural effusion

Post-1Y TB Focal patchy airspace disease (cotton wool shadows)CavitationFibrosisNodal calcification

Flecks of caseous material

PE Westermark’s sign (oligaemia in area of involvement)Increased size of hilum (thrombus impaction)Atelectasis with elevation of hemidiaphragm and linear densitiesPleural effusionConsolidationHamptom’s hump

Pleural effusion CCF, infection, trauma, PE, tumour, autoimmune disease, renal Failure; if large, more likely CaErect: blunting CP angle (lateral on PA, posterior on lat); 200ml to see on PA, 75ml to see on LatSupine: graded haze, denser at base; vascular shadows can be seen through effusion; if large, fluid cap over apex; do lateral decubitus

Pneumothorax Best seen on expiration

On supine film:Sign DescriptionEtched Diaphragm Diaphragm contrasted with air in pleural spaceEtched Mediastinum Mediastinum (heart border) outlined with air in the pleural spaceDeep Sulcus Sign Abnormally prominent/deep costophrenic angleVisible Visceral Pleura Most often seen as a doublediaphragm-like appearanceMediastinal shift As in the erect position, mediastinal shift may indicate the presence of a pneumothorax under tensionUneven Lung Density Affected lung may appear abnormally translucent. Abnormal lung may also appear abnormally opaque in

hydropneumothorax from veiling densityAbsent Lung Markings This will usually occur in the presence of other signs

Etched diaphragm (R; R lung edge also visible):

Etched mediastinum (L)

Deep sulcus sign (R CP angle)

Visible lung edge (this is subpulmonary pneumothorax):

Hydropneumothorax: trauma, thoracentesis, surgery, ruptured oesophagus, empyema

Interstitial Pul Fibrosis: idiopathic, collagen vascular disease, cytotoxic agents, nitrofurantoin, pneumoconiosis, radiation, sarcoidosisGround-glass appearanceVolume loss with linear opacities bilaterallyHoneycomb lung

Emphysema: hyperinflation with flattening of diaphragmsIncreased retrosternal spaceBullae (have no vessels and are not perfused)Enlargements of PA / RV

Anterior mediastinal mass: Terrible lymphadenopathyThymic tumourTeratomaThyroid massAortic aneurysmPericardial cystEpicardial fat pad

Middle mediastinal mass: LymphadenoapthyHiatus herniaAortic aneurysmThyroid massDuplication cystBronchogenic cyst

Posterior mediastinal mass: NeoplasmLymphadenopathyAortic aneurysmAdjacent pleural / lung massNeurenteric cystLateral meningocoele

Pleural mass: Mets (esp adenocarcinoma and malignant thymoma)Loculated pleural effusionMalignant mesotheliomaAsbestosis and pleural plaquesLymphoma

Extrapleural mass: Rib tumourRib infectionNeurofibroma / schwannomaLipoma

Pericardial effusion: globular enlarged heart shadowFat pad sign: soft tissue stripe >2mm between epicardial fat (blue arrows) and ant mediastinal fat (red arrows) seen anterior to heart on lateral view400-500ml fluid present to be seen on CXR

Pneumomediastinum: streaky lucencies over mediastinum extending into neckElevation of parietal pleura along mediastinal borders

Asthma, surgery, traumatic tracheobronchial rupture, abrupt changes in intrathoracic pressure (eg. coughing, vomiting), ruptured oesophagus, barotraumas, cocaine

Hilar lymphadenopathy: inflammation (sarcoidosis, silicosis)Neoplasm (lymphoma, metastases, bronchogenic carcinoma)Infection (TB, histoplasmosis, infectious mononucleosis)

DD: enlarged pulmonary arteries (appears more smooth)

Lung Ca: adenocarcinoma (35-50%): peripheralSCC (30%): central, hilar involvement, cavitation commonSmall cell (15-20%): central; hilar and mediastinal massesLarge cell (10-15%): peripheral; large; cavitation presentBronchoalveolar (3%): peripheral; rounded; air bronchogramsCarcinoid (<1%): well-defined endobronchial lesion