Purpose: Computed tomographic pulmonary angiography (CTPA) is the test of choice for patients with acute chest pain and suspected pulmonary embolism (PE). This examination is excellent for the diagnosis of PE and can also often identify alternative diagnoses. The early phase of contrast, however, may not allow for optimal evaluation of lymph nodes, serosal surfaces, and solid organs, leading to the nonvisualization of important findings and the potential for missed diagnoses. The purpose of this study was to determine the frequency of relevant findings only identified on standard portal venous phase CT compared with CTPA.
Materials and methods: The reports for all patients in the previous 10 years who underwent both standard CT and CTPA within 7 days, for a total of 675 pairs of scans, were tabulated according to the presence of PE, serosal abnormalities, solid organ abnormalities, and lymphadenopathy. All findings were categorized as present on both scans, standard CT only, or CTPA only. The scans were manually evaluated to exclude findings that were new or resolved on the second study or outside the field of view on one of the studies.
Results: Significantly more PEs were identified only on CTPA examinations. However, significantly more pleural, peritoneal, and solid organ abnormalities, and abnormal mediastinal and abdominal lymph nodes were identified on standard CT only. There was no significant difference in the identification of pericardial abnormalities or abnormal hilar lymph nodes between the two scans.
Conclusions: Many serosal abnormalities, solid organ abnormalities, and lymphadenopathy were only reported on standard portal venous phase CT compared with CTPA.