3Features that are typically examined on a chest X-ray Every doctor will have a different approach to examining chest X-rays. A commonly used mnemonic for what to look for on a chest X-ray is:It May Prove Quite Right (but) Stop And Be Certain How Lungs Appear
4I = Identification (name, age, sex, indication for X-ray) M = Markers (differentiate left from right )P = Position - the spinous process of T4 should be between the heads of the clavicle (if it isn't the body is rotated)
5Q = Quality - is the film penetrated properly Q = Quality - is the film penetrated properly. In a properly penetrated film the vertebral interspaces should be visible behind the central (cardiac) shadowR = Respiration - chest X-rays are typically done with full inspiration(but)
6S = Soft tissue - look for subcutaneous emphysema (suggestive of trauma), soft tissue swelling A = Abdomen - look for free abdominal air (suggests penetrating trauma, peritonitis, or recent surgery)B = Bone - look for fractures (these tend to be at the lateral aspects because of the mechanics
7C = Central shadow (cardiac silhouette) - greater than 50% of lateral distance in frontal view at the diaphragm suggests cardiac enlargement (usually secondary to heart failure) or a pericardial effusion . A widened mediastinum may suggest aortic dissection
8H = Hila (of the lungs) - can be affected in lung disease, malignant processes and infection (hilar lymphadenopathy).L = Lungs - for consolidation, interstitial lung disease (reticular, nodular or reticulonodular), honeycombing, miliary pattern, granulomas, lung massesA = Absent structures/Apices of the lung (for pneumothorax)
9Technique tips Sometimes the film may have been taken at an angle The silhouette signTo identify PA or AP film
10Effect of over- and underexposure on a chest x-ray. Overexposure (A) Underexposure (B
11Nipple shadows. midclavicular line over the lower half of both the right and the left lung (arrows). These should be bilateral
15Situs inversus. The heart, stomach, and liver are all in reversed positions. Before you make this diagnosis, make sure that the technician has placed the right and left markers correctly.
16Lung volume can be estimated by observing the point where a posterior rib crosses the dome of the diaphragm. Normal for PA film - 9th or 10th posterior rib.This point is at the 8th or 9th ribs in older patients
17Free gas under the diaphragm indicates bowel perforation Free gas under the diaphragm indicates bowel perforation. Note that this sign is only likely to be seen if an erect film is taken
21Pulmonary infiltrates Atelectasis/collapse Loss of lung volumeAnatomy shifts towards atelectasisLinear, smooth, wedge-shapedApex of opacity starts at hilum Consolidation Normal lung volumeNo anatomical shiftConsolidationAir bronchograms can occur in both.
23PneumoniaSevere pneumonia is classically manifested by airspace disease and consolidation (alveoli and bronchioles that are completely filledAir bronchograms may occur (air in larger bronchi, outlined by consolidated surrounding parenchyma)Other radiographic features include:interstitial infiltrates that may be the only manifestation or may coexist with consolidative changes.± associated parapneumonic effusion
34Pulmonary Embolism CXR Findings: Normal Atelectasis Increased size pulmonary artery, azygos, SVCElevated hemidiaphragmEdema away from site of PEWestermark's signOligemia of lung beyond occluded vesselMay be localized, unilateral, or widespreadUsually associated with increased size of pulmonary artery (Fleischner's sign)Hampton's HumpAssociated with PE with infarctionTriangular or rounded density at periphery or pleural basedBest seen hours after event