Ancillary lung parenchymal findings at spiral CT scanning in pulmonary embolism. Relationship to chest sonography.

Introduction/objective: The aim of the study was to compare findings of transthoracic sonography (TS) and of spiral computed tomography (sCT) in patients with suspected pulmonary embolism (PE).

Methods And Patients: Peripheral parenchymal and pleural findings of TS and sCT were compared in 62 patients (25 females, 37 males; mean age 62.2 years) with suspected PE.

Results: In 39 patients PE was established, of whose pleura-based lesions could be detected by TS in 30 patients and by sCT in 31 patients. Whilst in three of the patients parenchymal lesions were exclusively detected by sonography, no peripheral abnormalities could be discovered with either technique in five patients. Among the nine patients lacking peripheral abnormalities on sonography, four revealed peripheral lesions in sCT. In 23 patients without PE, peripheral consolidations at CT were detected in six patients whereas two showed lesions on TS. With respect to the appearance, pleura-based wedge-shaped consolidations were the main parenchymal alterations (82.4% at TS, 66.1% at sCT) as compared with non-wedge-shaped consolidations (17.6% at TS, 33.9% at sCT). Peripheral lesions were located preferentially within the lower lobes. In addition, both localised and basal pleural effusion associated with PE could be demonstrated in 58.9% at TS and in 23.1% by sCT.

Discussions And Conclusion: The study shows that in PE parenchymal and pleural changes are detectable by TS and sCT. If parenchymal findings are present at sCT, peripheral PE should be considered, even in the absence of directly visible emboli.