Sonographic observation of pulmonary infarction and early infarctions by pulmonary embolism

Fifty-eight consecutive patients with clinical symptoms of pulmonary embolism/infarction were examined by ultrasound as the first imaging modality. The diagnosis was confirmed in 35 patients by ventilation-perfusion scintigraphy; 13 underwent pulmonary angiography for verification of clinical diagnosis. Seven patients died, necropsy was performed and the diagnosis of pulmonary embolism was confirmed in six cases; three patients were submitted to transthoracic lung biopsy. Intercostal space and an additional small pleural effusion in 48% of the examined patients served as a sonic window for the 5 MHz sector scanner. In 42 of the 54 cases with a final diagnosis of pulmonary embolism/infarction a total of 69, hypoechoic, lesions with a pleural basis were detected. These were conspicuous, predominantly triangular, of a mean size 4.6 x 3.7 cm (range 9 x 8 to 2 x 1.5). A hyperechoic structure with reverberation artefacts suggestive of air was frequently visible in the centre: a sign of segmental involvement. The ultrasound examination yielded a true positive result in 41 cases. The overall sensitivity was 98% and the specificity 66%. The prevalence of pulmonary embolism was 83% and the diagnostic accuracy 90%. This suggests that chest sonography can be an efficient technique in the detection of pulmonary infarction.