title: Clinical usefulness of imaging performed after CT angiography that was negative for pulmonary embolus in a high-risk oncologic population.
abstract: OBJECTIVE
  The purpose of our study was to determine the prevalence and types of additional imaging examinations that were performed, and whether anticoagulation therapy was started or continued, after CT angiography showed no pulmonary embolus in a high-risk oncologic population.
  
  
  METHODS
  We reviewed the radiology report for each CT angiogram that was obtained for clinically suspected pulmonary embolism at our institution (a tertiary cancer center) during a 25-month period. The radiology information system was then searched for any additional confirmatory radiologic examinations performed within 2 days after a negative finding on CT angiography. Medical records were reviewed to determine whether anticoagulation therapy was started or continued despite a negative finding on CT angiography.
  
  
  RESULTS
  Two hundred seventy-six CT angiograms were obtained in 260 oncology patients who were clinically suspected of having pulmonary embolism. The findings from 203 CT angiograms (74%) were interpreted as negative; 56 (20%), as positive; and 17 (6%), as equivocal for pulmonary embolism. Fifty-eight patients (21%) with negative findings on CT angiography subsequently underwent additional imaging, the results of which were potentially clinically important in 6% of the patients. Six patients began to receive and two continued to undergo anticoagulation therapy despite negative findings on CT angiography; three of the six patients received anticoagulation for new-onset atrial fibrillation.
  
  
  CONCLUSIONS
  Negative results of CT angiography for pulmonary embolism did not deter referring physicians from ordering other confirmatory imaging tests in 21% of patients in a high-risk oncologic population. Those additional tests rarely revealed results that might have been clinically important.
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA.
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Ginsberg
authors.forename: Jeana
authors.initials: J
authors.lastname: Oh
authors.forename: Adam
authors.initials: A
authors.lastname: Welber
authors.forename: David M
authors.initials: DM
authors.lastname: Panicek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D000925:Anticoagulants / Q000008:administration & dosage; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging / Q000706:statistics & numerical data; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000209:etiology; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000925:Anticoagulants