How to Read a CXR
Proforma
Patient and CXR data: projection, posture
Adequacy: easily visible mid-thoracic IV spaces
Degree of inspiration – diaphragm at levels of 8th -11th ribs posteriorly (or 5th - 6th ribs anteriorly)
Degree of rotation – central spinous processes of thoracic vertebrae, equidistant from medial ends of
clavicles
Airway: Trachea: central; slight deviation to R as crosses aortic arch
Pushed away: large pleural effusion; large/tension pneumothorax; aortic aneurysm;
mediastinal mass
Pulled towards: collapse; pul fibrosis; lobectomy, pneumonectomy
Breathing: Lungs, Pleura (effusion, thickening, calcification)
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, pneumothorax
Decreased lucency towards diaphragm = alveolar / interstitial fluid, effusion,
Consolidation
Air bronchogram: tubular outline of an airway made visible by filling of the surrounding
alveoli by fluid or inflammatory exudates
Caused by: lung consolidation; pulmonary edema; nonobstructive pulmonary
atelectasis; severe interstitial disease; neoplasm; normal expiration
Circulation: Heart: 1/3 to R of thoracic spinous processes, CTR <50%
R heart border = RA; Poor distinction = consolidation of RML
L heart border = LV; Poor distinction = lingular consolidation
Increased CTR = AP film; LVD, CCF, pericardial effusion
Pulmonary vessels
Diaphragm: R higher than L by 1-3cm
Loss of outline = fluid, consolidation or collapse
Flat diaphragm = COPD
Gas under diaphragm = rupture of hollow viscus; Post-laparoscopy
Mediastinum: Hila: at T6-7 level; made of pul arteries and veins; L hilum 1-2cm higher and square
shaped; R hilum V shaped
Width: <8cm superiorly on PA at carina (or >25% diameter of chest)
Wide: AP view; unfolded aortic arch, thoracic AA, aortic rupture; mediastinal
lymphadenopathy; retrosternal thyroid, thymoma; paravertebral mass;
oesophageal dilation
Bones: lesions or fractures
Soft tissues: don’t miss mastectomy
Tubes
Views
Describing abnormalities: mediastinal / central / peripheral; UZ/MZ/LZ (according to lobe if lateral film
available); number; size; shape; effects on adjacent structure
PA:
Preferred view
Transverse fissure: from Jx of upper 1/3 and lower 2/3 lateral chest to R hilum
Lat:
Helps delineate and localize masses, lesions or consolidation – esp if they are obscured by heart
and diaphragm
L image, L lung: oblique fissure, as shown from T4 to 3cm post to where diaphragm and sternum meet
R image, R lung: horizontal and oblique fissures, as shown
ÂP:
Magnifies heart and mediastinum
Associated with rotational artefact
Expiratory: helpful for small pneumothroax / gas trapping with FB
Neonatal CXR
Atelectasis
Consolidation
Lobe collapse
Heart 60-65% chest width
Bronchial branching may give sense of air bronchograms
Thymus (involution occurs age 6yrs; not usually seen after 2yrs;
is anterior on lateral; L lobe larger than R; extends as low as 4th
costal cartilage; lung markings visible through it; does not
displace trachea)
Neonatal RDS: miliary nodulation in lower zones / diffuse; ground glass; air bronchogram
CF: bronchiectasis, peribronchial consolidation
Varicella pneumonia: widespread nodules
Collapse or incomplete expansion of the lung or part of the lung  segmental/subsegmental collapse 
linear/curvilinear/wedge-shaped increased density with apex at hilum; often assoc with volume loss;
shift towards; may be compensatory hyperinflation of adjacent lobes, or hilar elevation / depression; air
bronchogram can occur
Compression: In lumen: mucus plug
In wall: tumour, scarring, TB, post-radiation
Extrinsic: LN’s, pleural effusion
Describe: homogenicity, discreteness of margin, cavitation, effect on heart border
Fluid (inflammatory, aspiration, pneumonia)
Cells (bronchoalveolar Ca, sarcoidosis, lymphoma)
Protein (alveolar proteinosis)
Blood (pul haemorrhage – Goodpastures, high altitude, bleeding disorders, mitral stenosis)
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 pathology
Note, pathology in posterior pleural cavity and lower mediastinum cause overlap but not obliteration of
heart border
Look for: loss of vol of lobe, loss of lucency, displacement of fissures, wider spacing of vascular shadows
of rest of lung
LUL collapse
Loss of aortic knuckle and upper L heart border
Retrosternal band of opacity with well defined oblique fissure on lateral
LLL collapse
RUL collapse
Loss of L hemidiaphragm and descending aorta
Triangular opacity between heart shadow and spine on lateral
Loss of ascending aorta and upper R heart border
Opacity at RUZ apex of mediastinal border
Deviation of trachea to R
RML collapse:
Loss of R heart border (vague R pericardiac haze)
On lateral, 2 fissures start to approximate (depression of horizontal) causing wedge opacity pointing to
hilum
RLL collapse:
R heart border unaffected
Triangular density posteromedially
Loss of R hemidiagphragm
Lingular consolidation: loss of L heart border
Pneumonia
Interstitial
lung disease
SHITFACED
Airspace opacity / lobar consolidation / interstitial opacities
Normal/incr volume (volume loss NOT seen); no shift; not centred at hilum; can cause air bronchograms
Lobar: strep pneumoniae; uniform opacity confined to one lobe; air bronchograms seen; may be ill
defined if not adjacent to one of the fissures; may be small assoc pleural effusion
Lobular: staph; multifocal, patchy
Lower zones: legionella
Upper zones: klebsiella
Round pneumonia: C Burnetti, S pneumoniae, L pneumophilia, S aureus
Bronchial: ill defined areas of patchy opacity (eg. Post-op, aspiration)
Diffuse: community acquired, nosocomial, Immunocompromised
Miliary pattern / intersitital: TB, varicella pneumonia; air bronchogram not seen
Sarcoidosis
Histiocytosis
Idiopathic
Tumour: mets, lymphangitis
Failure
Autoimmune: SLE, RA, scleroderma, polymyositis;
granulomatosis; hypersensitivity pneumonitis
Collagen vascular disease
Environmental: Asbestos, silicosis, farmer’s lung, coal
Drugs: Methotrexate, amiodarone
Other: atypical pneumonia, fungal, viral; radiation
pneumonitis
Lung asbcess
Bacterial: staph aureus, Klebsiella, anaerobes, G-ives, TB,
aspiration pneumonia; bronchial obstruction; if multiple,
think of R sided bacterial endocarditis
Fungal (eg. Aspergillosis, cryptococcal)
If assoc with pleural effusion: staph aureus, anaerobes, Gives, TB
Immuncompetent: anaerobes more common
Immunocompromised = staphs
2-10% mortality if community acquired, 60% if hospital
acquired; shows AF level (present if communicates with
bronchioles; dense area of consolidation if doesn’t and will
need CT to diagnose)
Cavitating
lung lesions
CAVITY
Cancer: more likely if anterior; esp if SCC; advanced Hodgkins
Autoimmune: granulomatosis, sarcoidosis, Wegener’s RA, progressive massive fibrosis
Vascular: septic emboli and pul infarct
Infectious: 2Y TB, abscess, cocci, infected bullae / cysts
TB
Pleural
effusion
ARDS
PE
Trauma: traumatic cyst
Young: bronchogenic cyst, laryngotracheal papillomatosis
1Y  small area consolidation in lower UL or upper LL, adenopathy, pleural effusion
Post-1Y TB  hilar LN calcification, small calcified nodule (Ghon focus)
2Y  cavitating lung lesions with surrounding fibrosis (esp in UL with elevation of hila and incr lucency of
remaining lung fields), focal patchy airspace disease, no hilar lymphadenopathy
Miliary  1-2mm diffuse nodules
Erect: blunting CP angle (lateral on PA, posterior on lat); >100ml to see on PA, 75ml to see on Lat; upper
margin should be concave – if flat, also pneumothorax; can cause tracheal shift (unlike consolidation)
Supine: graded haze, denser at base; vascular shadows can be seen through effusion; if large, fluid cap
over apex; do lateral decubitus
Causes: CCF, infection, trauma, PE, tumour, autoimmune disease, renal failure; if large, more likely Ca
R sided – Meig’s syndrome (ovarian Ca)
L sided – pancreatitis, chylothorax, CCF
Bilat pul infiltrates with air bronchograms occuring after 12hrs
 clearing after 5/7  fibrosis with reticular pattern after 7/7
Westermark’s sign (oligaemia in area of involvement); Hampton’s hump
Increased size of hilum (thrombus impaction); Atelectasis with elevation of hemidiaphragm and linear
densities; Pleural effusion; Consolidation
CCF
Upper lobe diversion (upper lobe vessels usually smaller
than lower), basilar and hilar infiltrates, widening of
vascular pedicle, peribronchial cuffing, Kerly B lines (also
found in silicosis, lymphagnitis carcinomatosis,
sarcoidosis), CTR >0.5 (>0.7 in infants), pleural effusions;
XR more sens than examination
Pulmonary
nodules
Benign: unchanged for two years is almost certainly benign; completely calcified or central or stippled
Calcium; solitary
Suspicious: nodules with irregular calcifications or those that are off center; Multiple nodules; 1Y
tumours don’t calcify, may have satellite lesions; 1Y poorly defined; may show umbilication; may have
linear strands connecting to hilum (lymphatics), usually double in size in 1-6/12
Solitary pul nodule: 30-40% malignant; <3cm
Adenoma: usually central, hilar, smooth and round; 1% of all neoplasms
Neoplasia: assoc with collapse, hilar enlargement, elevated hemidiaphragm, bony destruction, lines
lymphatic infiltration with connects to hilum
Mets: usually more sharply defined than 1Y; multiple; colon, breast, renal cell, testicular, TCC,
melanoma
If diffuse rather than nodular: prostate, stomach, pancreas, lymphoma, thyroid
If calcify: breast, osteogenic Ca, thyroid, ovarian, mucinous adenoCa
Adenocarcinoma (35-50%): peripheral
Emphysema
Pulmonary
fibrosis
SCC (30%): central, hilar involvement, cavitation common
Small cell (15-20%): central; hilar and mediastinal masses
Large cell (10-15%): peripheral; large; cavitation present
Bronchoalveolar (3%): peripheral; rounded; air bronchograms
Carcinoid (<1%): well-defined endobronchial lesion
Other: lymphoma
Infection (round pneumonia (esp children and young adults; C Burnetti, S pneumoniae, L pneumophilia, S
aureus); atelectasis; abscess; miliary TB (cavitation, calcification), varicella pneumonia, histoplasmosis,
aspergilloma, fungal, Nocardia infection, hydatid disease
Vascular: AVM, haemartoma (smooth 2-4cm lobulated with popcorn calcification), PE, infarct
Autoimmune: more likely multiple; granuloma, RA, Wegener’s, fibrotic lung disease (eg. Silicosis)
Other: pleural plaques, bronchial atresia, sequestration, chrondroma
Hyperinflation with flattening of diaphragms; Increased retrosternal space; Bullae (have no vessels and
are not perfused); Enlargements of PA / RV; reduced vascular markings esp in periphery; long thin heart,
clockwise rotation of heart; kyphosis and sternal bowing
Ground-glass (suggests idiopathic) / reticular
appearance; volume loss with linear opacities
bilaterally; multiple nodules
 Honeycomb lung;
SETCARP
Upper zone (SETCARP): Silicosis (multiple nodules, hilar LN with egg shell calcification)
Sarcoidosis (mediastinal > paratracheal nodes, calcification rare, miliary
nodulation and large nodules)
Eosinophilic pneumonia
TB
Coal miner’s pneumoconiosis, CF
Aspergillosis, ank spond
Radiation therapy
PCP, pneumoconiosis
BADRASH
Lower zone (BADRASH): Bronchiectasis
Aspiration
Drugs
RA
Asbestosis (shaggy heart from adhesions, pleural thickening and calcification,
mesothelioma)
Scleroderma
Hamman Rich syndrome, histiocytosis
BIGHIPS
Honeycomb (BIGHIPS): Bleomycin
Idiopathic
Granulomas
Histiocytosis
Interstitial pneumonia
Pneumoconiosis
Sarcoid
Drugs (methotrexate, nitrofurantoin, hydralazine, amiodarone), paraquat, smoke inhalation, ARDS
Pneumothora
x
Etched diaphragm (1) / mediastinum (2) : contrasted with air in pleural space; diaphragm may be flattened
Deep sulcus sign (3): abnormally prominent/deep lateral CP angle
Visible visceral pleura (4), Mediastinal / tracheal shift, Uneven lung density, Absent lung markings, subC
emphysema
DD: scapula, skin fold, bullae, companion shadow, post-pleurectomy, drain tube track line
Pneumomediastinum
Hydropneumothora
x
Streaky lucencies over mediastinum extending into neck
Elevation of parietal pleura along mediastinal borders
Causes: Asthma, whooping cough, surgery, traumatic tracheobronchial rupture, abrupt changes in
intrathoracic pressure (eg. coughing, vomiting), ruptured oesophagus, barotrauma, cocaine
Trauma, thoracentesis,
surgery, ruptured oesophagus,
empyema
Mediastinal
masses
Pleural masses
MALLETS
Extra-pleural
masses
Pericardial
effusion
Ant: between heart and sternum
Upper: LN’s, thyroid mass
Middle: LN, ascending aortic aneurysm, thymus, teratoma,
lipoma
Lower: fat pad, pericardial cyst, hernia
Middle: LN; Aortic aneurysm; pul art; Bronchogenic cyst
Post: between heart and spine
Upper: pharygneal pouch, neurogenic tumour
Middle: hiatus hernia, dlated oesophagus, descending aoric an.
Lower: hernia, neurogenic tumour, TB of spine, Hodgkins
Are broad based to chest wall, usually 2Y
Mesothelioma
Adenocarcinoma, asbestosis
Lymphoma, Leukaemia
Empyema (or loculated pleural effusion)
Thymoma
Splenosis
Rib tumour; Rib infection
Neurofibroma / schwannoma; Lipoma
Globular enlarged heart shadow; 400-500ml fluid present to be
seen on CXR (200ml for pleural effusion)
Fat pad sign: soft tissue stripe >2mm between epicardial fat
(blue arrows) and ant mediastinal fat (red arrows) seen anterior
to heart on lateral view
Hilar
lymphadenop
athy
Inflammation (sarcoidosis, silicosis)
Neoplasm (lymphoma, metastases, bronchogenic carcinoma)
Infection (TB, histoplasmosis, infectious mononucleosis)
May be vascular disease (eg, pul HTN – will have more smooth border)
Notes from:
See p 490 TinTin for non infectious causes of pul infiltrates