In patients with suspected PE, helical CT can be used safely as the primary diagnostic test to rule out PE. Serial compression ultrasonography has limited additional value.

Spiral CT angiography is an accurate method for the detection and exclusion of PE, with the exception of isolated subsegmental PE.

Background -A study was carried out to evaluate the potential place of spiral volumetric computed tomography (SVCT) in the diagnostic strategy for pulmonary embolism. Methods -In a prospective study 249 patients with clinical suspicion of pulmonary embolism were evaluated with various imaging techniques. In all patients

To cite this article: van Strijen MJL, de Monye W, Kieft GJ, Pattynama PMT, Prins MH, Huisman MV. Accuracy of single-detector spiral CT in the diagnosis of pulmonary embolism: a prospective multicenter cohort study of consecutive patients with abnormal perfusion scintigraphy. Summary. Background: Spiral computed tomography (CT) has emerged as a potentially conclusive diagnostic test to exclude pulmonary embolism (PE) in patients with non-high probability scintigraphy and is already widely used-sometimes as the sole primary diagnostic test in the diagnosis of suspected PE. Its true sensitivity and specificity has, however, not been evaluated previously in a large cohort of consecutive patients. Methods: In a multicenter prospective study 627 consecutive patients with clinically suspected PE were studied. Patients with normal perfusion scintigraphy were excluded from further analysis. Single-detector spiral CT scanning and ventilation scintigraphy were then performed in all patients to diagnose PE, while pulmonary angiography was performed as the gold standard. The only exceptions were those patients who had both a high-probability VQ scan and a CT scan positive for PE: these patients were considered to have PE and did not undergo additional pulmonary angiography. All imaging tests were read by independent expert panels. Results: Five hundred and seventeen patients were available for complete analysis. The prevalence of PE was 32%. Spiral CT correctly identified 88 of 128 patients with PE, and 92 of 109 patients without PE, for a sensitivity and specificity of 69% [95% confidence interval (CI) 63-75] and 84% (95% CI 80-89), respectively. The sensitivity of spiral CT was 86% (95% CI 80-92) for segmental or larger PE and 21% (95% CI 14-29) in the group of patients with subsegmental PE. Conclusion: The overall sensitivity of spiral CT for PE is too low to endorse its use as the sole test to exclude PE. This holds true even if one limits the discussion to patients with larger PE in segmental or larger pulmonary artery branches. We conclude that, in patients with clinically suspected PE and an abnormal perfusion scintigraphy, single-slice detector spiral CT is not sensitive enough to be used as the sole test to exclude PE.

The purpose of this study was to determine the prevalence of lower extremity deep venous thrombosis (DVT) in patients with suspected and proven pulmonary embolism (PE). A meta-analysis was performed, based on literature from January 1983 to June 1997. Papers obtained from a computer-aided literature search were divided into studies with pulmonary angiography or ventilation-perfusion (V/Q) scintigraphy as the reference study. Our own observational data of the prevalence of DVT in 149 patients suspected of PE were also reported. The estimated prevalence of DVT in patients with proven and suspected PE was calculated. In the 149 patients studied, the prevalence of DVT was 12% with suspected PE and 32% (95% confidence interval 20-46%) in patients with proven PE. The individual studies showed a considerable heterogeneity, the prevalence of DVT in proven PE ranged from 10 to 93%. The pooled estimate of the prevalence of DVT in patients suspected of PE, over all studies, was 18% (95% confidence interval 15-20%). The DVT prevalence in proven PE was 36% (95% confidence interval 22-52%) in the angiography-based studies, and 45% (95% confidence interval 33-58%) in the V/Q scintigraphy-based studies. In conclusion, the current meta-analysis shows that the prevalence of DVT in suspected PE is approximately 18%, and in proven PE 36-45%.