PULMONARY-EMBOLISM - PROSPECTIVE COMPARISON OF SPIRAL CT WITH VENTILATION-PERFUSION SCINTIGRAPHY

PURPOSE: To compare prospectively the accuracy of spiral computed tomo graphy (CT) with that of ventilation-perfusion scintigraphy for diagno sing pulmonary embolism. MATERIALS AND METHODS: Within 48 hours of pre sentation, 142 patients suspected of having pulmonary embolism underwe nt spiral CT, scintigraphy, and (when indicated) pulmonary angiography . Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermed iate-probability, respectively. RESULTS: In the 139 patients who compl eted the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six w ith embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scinti grams were discordant in 12 cases; diagnosis with spiral CT was correc t in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show e mbolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, resp ectively. CONCLUSION: In cases of pulmonary embolism, sensitivity of s piral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.