Purpose: To retrospectively assess outcome in patients with clinically unsuspected pulmonary embolism (PE) at chest multi-detector row computed tomography (CT).
Materials and methods: Institutional review board approval and informed consent were not required. PE was assessed in consecutive CT scans in 1966 patients (mean age, 60 years; range, 15-96 years; male-female ratio, 1.79) and graded with severity score. Studies with true-positive and false-negative radiologic diagnoses were determined. Coexisting morbidity, anticoagulant therapy (ACT), complications, and 1-year outcome were reviewed. Statistical evaluation included Mann-Whitney U test, chi(2) test, Poisson regression, and Kaplan-Meier statistics.
Results: Scans were PE positive in 117 patients. Clinical data review was complete in 96 patients; 63 of 96 patients had malignancy; in 58, PE was not suspected. In 38 of these 58 patients, radiology report findings were false-negative (mean severity score, 20.21 +/- 17.88 [standard deviation] and 9.55 +/- 7.12 for those with true-positive and false-negative findings, respectively; P = .012). Forty-nine patients received therapeutic ACT; 21, prophylactic ACT; and 26, no treatment. PE severity was higher in patients with therapeutic ACT versus those without (P < .001). Bleeding complications were more frequent with therapeutic ACT (two early deaths, five major nonfatal hemorrhages) than without (one minor hemorrhage; P = .037). There were eight early deaths (therapeutic ACT, seven; without ACT, one; P = .037). Positive predictors of early death included severity score >28, use of systemic thrombolytic therapy, occurrence of major hemorrhage, and new-onset cardiac or renal failure (P = .001-.043). Negative predictors were report with false-negative findings and no therapeutic ACT (P = .007-.037). Predictors of late death (n = 25) were older age, malignancy, and renal failure (P = .001-.043).
Conclusion: Clinically unsuspected PE may remain undetected at routine chest CT; these patients have favorable short-term outcome without therapeutic ACT.
(c) RSNA, 2006.