To determine the diagnostic accuracy of quad-slice helical computed tomography (HCT) in patients with suspected pulmonary embolus (PE), using digital subtraction pulmonary arteriography (DSPA) as the gold standard.
All patients with ventilation/perfusion scans that were indeterminate or contrasted with clinical suspicion were screened. Patients were eligible for the study if: ≥18 years of age, had a serum creatinine ≤1.5 (unless on chronic dialysis) and were able to give informed consent. DSPA was performed using digital subtraction technique. HCT was performed on the MX 8000 scanner (Picker International; Cleveland, OH) using quad-slice helical technique. Interpretations of the DSPA and HCT images were performed by 3 independent radiologists for each procedure. Reviewers were blinded from each other’s interpretations and from the other diagnostic test. Sensitivity and specificity were computed using a majority rule algorithm. The Kappa statistic for multiple raters was calculated for each modality.
A total of 100 patients were enrolled with an average age of 56 (19–88). 7 patients failed to complete both diagnostic studies, thus 93 patients comprised the study group. 18 (19.4%) patients were diagnosed with acute PE by DSPA. PE locations were 0% main, 14% lobar, 44% segmental and 42% subsegmental. The sensitivity, specificity and diagnostic accuracy of HCT was 100%, 89% and 91%, respectively. Kappa values were 0.71 and 0.83 for HCT and DSPA, respectively.CONCLUSIONS: Quad-slice HCT is a sensitive and specific diagnostic test for suspected acute PE.
HCT is a less-invasive and less-expensive diagnostic test than DSPA. The diagnostic accuracy appears favorable, but further study is required.
M.D. Williams, Eli Lilly and Company, Shareholder.