Update in General Internal Medicine

Thromboembolic Disease

Helical Computed Tomography Was an Acceptable Primary Diagnostic Test for Ruling Out Pulmonary Embolism

This study examined whether helical computed tomography (CT) of the pulmonary arteries is sufficiently accurate to be the primary diagnostic test for pulmonary embolism (PE). Computed tomography has several advantages over the current “gold standard” test—pulmonary arteriography—because it is noninvasive and can also detect alternative diagnoses. However, its ability to detect very small clots is a potential disadvantage compared with pulmonary arteriography.

At 3 hospitals in the Netherlands, 510 patients underwent helical CT within 24 hours of admission for signs and symptoms of PE, including sudden, unexplained shortness of breath; worsening of chronic obstructive pulmonary disease (COPD); pleuritic chest pain; or hemoptysis. Any patient who had received anticoagulants for more than 24 hours was excluded. An elevated serum creatinine level was not a contraindication for administering contrast medium. When the CT scan was normal or inconclusive, the investigators performed compression ultrasonography on the same day as the CT and, if findings on the first compression ultrasonography were normal, also on days 4 and 7. Investigators prescribed anticoagulants for all patients with a positive result on CT or ultrasonography. Other patients did not receive anticoagulants. Patients received a 6-week and 3-month follow-up examination.

Computed tomography results were positive for PE in 24% (n = 124) of the 510 patients and resulted in an alternative diagnosis in 25.5% (n = 130). Alternative diagnoses were pneumonia (51%), malignancy (17%), pleural effusion (8%), congestive heart failure (8%), COPD (5%), and other diagnoses (11%). The CT scan could not be interpreted in only 8 patients, was not obtained in 2, and was normal in the rest. Among patients with a normal …