Incidental abnormalities found on CT pulmonary angiograms performed for suspected acute pulmonary embolism

Abstract

A CT pulmonary angiogram (CTPA) is performed commonly in the investigation of suspected pulmonary embolism (PE). Other lung, mediastinal and pleural pathologies of clinical importance may be found incidentally, not suspected from the chest X-ray (CXR). We studied 500 sequential CTPA scans done for suspected PE in a community hospital to assess the nature and frequency of any pulmonary pathology first suggested by the CTPA, with particular reference to pneumonia not diagnosed on the CXR. All CXR and scans were reviewed by a radiologist as well as the treating clinicians.

PE was found in 123 of 500 (24.6%) scans. 110 of 500 (22%) scans showed evidence of pneumonia. Out of these 110 scans, 55 had no evidence of pneumonia on the CXR (of which 63% had been taken within 48 hours of the CTPA). Other pathologies were seen on 145 of 500 scans (29%).

Conclusion: This study is suggestive of a high incidence of pneumonia in patients scanned for suspected PE, half of whom had no consolidation in the initial CXR. This raises questions concerning the reliability of clinical decisions that rule out pneumonia when there is no consolidation on a CXR.