If the films are incomplete or unacceptable, repeat them or order another test. In the interpretation of the chest radiograph, the first concern is to assure the adequacy of the film. The entire thorax should be seen, including the apices, lateral chest walls, entire diaphragm and both costophrenic angles. Failure to assure adequacy of the film may lead to significant diagnostic error. 

Thoracic width is measured at the widest point, i.e., the lung base. Failure to appreciate this point may lead to errors in assessing the cardiothoracic ratio and mediastinum:chest width ratio.

When evaluating for a possible pneumothorax, films must be reviewed carefully since small pneumothoraces can easily be missed and overlying skin folds can simulate pneumothoraces. Look for a deep sulcus or for subcutaneous air as indirect markers of a pneumothorax.

The CXR gets a relatively low ACR appropriateness rating for adults less than 40 years of age with acute respiratory symptoms, negative physical examination, and no other signs, symptoms or risk factors for pulmonary disease. Overuse of the CXR in this population is a common problem and may contribute to avoidable delay in clinical management and disposition decisions.

Chest radiograph cannot, by itself, be used to differentiate between viral and bacterial disease.

In the setting of acute asthma, the chest radiograph is indicated only when pneumonia or pneumothorax is suspected or the diagnosis of asthma has not yet been established

Almost one-fourth of radiographic abnormalities seen in patients with apparent exacerbations of chronic obstructive pulmonary disease are not predictable on the basis of high-risk criteria. Routine chest radiography should be considered.

The chest radiograph is often included in the work-up of the hypertensive patient, presumably to evaluate for the presence of left ventricular hypertrophy (LVH). However, the CXR is insensitive for the detection of LVH and is not clearly indicated in uncomplicated hypertension. Echocardiography is the best modality for the detection of LVH.

Obtaining an echocardiogram is a class I recommendation for the evaluation of chest pain in patients with suspected acute myocardial ischemia, when baseline ECG and laboratory markers are non-diagnostic and when the study can be obtained during pain or within minutes after its abatement. ECHO is not indicated for chest pain of apparent noncardiac etiology, nor is ECHO indicated for patients who have ECG changes diagnostic of myocardial ischemia/infarction.

Chest radiographic findings are often abnormal in the presence of aortic dissection and CXR has a reported sensitivity of 90%. However, the presence of a normal aorta and mediastinum only decreases the probability of dissection; it does not exclude it.