Bottom line: While no individual CXR finding is diagnostic, some findings (when present, see below) do increase risk for PE. Absence of abnormal findings are not helpful.
Summary: Worsley DF, et al. Chest radiographic findings in patients with acute pulmonary embolism: observations from the PIOPED Study. Radiology. 1993 Oct;189(1):133-6.
The Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) included 1,063 patients with suspected PE. PE was confirmed in 383 patients and excluded in 680 patients. RESULTS: In patients with confirmed PE, 78% had an abnormal chest x-ray. Table 1 (p. 134) summarizes the sensitivities and specificities of various x-ray findings.
|Enlarged central artery||20%||80%|
Elliott CG, et al. Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry. Chest 2000; 118:33 – 38.
This observational study included 2,454 consecutive patients with a diagnosis of pulmonary embolism at 52 hospitals 1994-1996. Chest x-rays were available for 2,322 (95%) patients. RESULTS: 78% of the x-rays were abnormal. Most common abnormal findings in these x-rays included cardiac enlargement (27%), pleural effusion (23%), elevated hemidiaphragm (20%), PA enlargement (19%), and atelectasis (18%). For 1,084 patients who also received echocardiogram, the chest x-ray finding of cardiomegaly had sensitivity of 0.48 and specificity of 0.63 for right ventricular hypokinesis found on the echocardiogram and associated with acute pulmonary embolism. Likewise in these patients, the x-ray finding of PA enlargement had sensitivity of 0.38 and specificity of 0.76 for the same finding on echocardiogram.