Precision pulmonary angiography for the diagnosis of massive and small pulmonary thromboembolism using dual-slice spiral computed tomography.

OBJECTIVE: To evaluate the potential value of precision dual-slice spiral computed tomographic pulmonary angiography (DSCTPA) in the diagnosis of pulmonary thrombo embolism (PTE), especially small PTE.

METHOD: Seventy-four patients sus Pected of having PTE received DSCTPA. The diagnosis was confirmed in all cases by D-dimer, blood P((A-a))O(2) and cardiac sonography, by direct pulmonary angiography (DPA)in 12, by ventilation-Pe rfusion scan (V-PS) in 6, and 28 underwent lower extremity sonography.

RESULTS: DSCTPA revealed central pulmonary thromboembolism (CPTE) in 24 cases and Peripheral pulmonary embolism (PPTE) in 34 cases; true negative in 10 cases, false positive in 3 cases and false negative in 3 cases. Direct signs included partial filling defect (60%), complete occlusion (31%), railway-track sign (3%), mural filling defect (2%), low perfusion and varied lung density (4%). Indirect signs included pulmonary artery dilatation in 16 cases (28%), focal fine pulmonary blood vessels 28 (48%), mosaic sign 4 (7%), effusion 9 (16%), atelectasis 9 (16%), cuniform change 5 (9%), ground glass shadow 7 (12%) and lymphnode enlargement 5 (9%). DSCTPA was more sensitive than V/QS scanning (P < 0.001) and DPA (P < 0.001) in the PPTE group. The sensitivity was 92%, specificity 77%, accuracy 88%, positive predictive value 92%, and negative predictive value 77%.

CONCLUSION: DSCTPA is a noninvasive, effective and reliable method for diagnosing PTE, especially small PTE, for which it could increase the detection rate.