Radiology 2000 May;215(2):535-42
Subsequent pulmonary embolism: risk after a negative helical CT pulmonary
angiogram--prospective comparison with scintigraphy.
Goodman LR, Lipchik RJ, Kuzo RS, Liu Y, McAuliffe TL, O'Brien DJ
Department of Radiology, Division of Pulmonary Medicine and Critical Care Medicine, 9200 W
Wisconsin Ave, Milwaukee, USA. [email protected]
PURPOSE: To determine whether a helical computed tomographic (CT) scan that is negative
for pulmonary embolism (PE) is a sufficiently reliable criterion to safely withhold
anticoagulation therapy. MATERIALS AND METHODS: Patients with negative helical CT scans
were prospectively compared with patients with negative or low-probability scintigrams. In
a 460-bed university hospital and clinic, 1,015 adult patients underwent either
scintigraphy or helical CT for possible PE for 25 months. Five hundred forty-eight
patients who had negative images and were not receiving anticoagulation therapy were
prospectively followed up for 3 months for clinical, new imaging, death certificate, or
autopsy evidence of subsequent PE. Ninety-seven patients were lost to follow-up. RESULTS:
Subsequent PE was found in two (1.0%) of 198 patients with negative CT scans, none of 188
patients with negative ventilation-perfusion (V-P) scans, and five (3.1%) of 162 patients
with low-probability V-P scans (not statistically significant). Patients in the helical CT
group were hospitalized more often, had more severe disease, had more substantial PE risk
factors, and had a higher death rate. No deaths were attributed to PE in either group.
CONCLUSION: The frequency of clinical diagnoses of PE after a negative CT scan was low and
similar to that after a negative or low-probability V-P scan. Helical CT is a reliable
imaging tool for excluding clinically important PE.
PMID: 10796937, UI: 20257003
