A PROSPECTIVE, COMPARATIVE-STUDY OF VENTILATION-PERFUSION SCINTIGRAPHY AND CLINICAL-EVALUATION VERSUS DIGITAL SUBTRACTION ANGIOGRAPHY IN ACUTE PULMONARY THROMBOEMBOLISM

Patients with symptoms of acute pulmonary thromboembolism (APE) of sho rt duration were investigated with digital subtraction angiography (DS A) and ventilation/perfusion lung scintigraphy (V/Q scan), and a stand ardised clinical evaluation was performed. Forty-six angiograms (96%) were diagnostic the segmental level and were used as reference. In all V/Q scans classified as normal or of high probability for APE, a comp lete agreement with DSA was found. In scan categories with low or inte rmediate probability, where the, incidence of APE was 32%, there was c onsiderable inter-observer at disagreement. Clinical assessment alone was of limited value, but in patients with low clinical suspicion no A PE was found. The results indicate that normal and high probability V/ Q scans are very reliable; for excluding and identifying APE, respecti vely, also that fairly large APE cannot be diagnosed with lung-scannin g. Subdivision of V/Q scans into more than three categories (normal, h igh probability and inconclusive) seems to be of no practical value. U sing a pulsed sequence technique, high frame rate and central injectio n, DSA is a valuable clinical tool for diagnosing APE down to the segm ental level.