title: The effect of single-detector CT versus MDCT on clinical outcomes in patients with suspected acute pulmonary embolism and negative results on CT pulmonary angiography.
abstract: OBJECTIVE
  We sought to compare the clinical outcomes of patients in whom pulmonary embolism (PE) has been ruled out with single-detector CT versus MDCT, given the improved visualization of subsegmental clots with the latter and the recent increase in use of CT for evaluation of PE.
  
  
  METHODS
  Two cohorts of patients undergoing CT for suspected PE with either single-detector CT (3-mm collimation and pitch of 1.7) or MDCT (2-mm collimation and pitch of 1) scanners were prospectively observed and compared using predefined criteria for evidence of subsequent thromboembolic disease during the 6 months after the acquisition of their initial scan.
  
  
  RESULTS
  Ninety-eight patients were scanned using a single-detector CT scanner. Of these, none had evidence of subsequent PE or deep venous thrombosis (DVT), and six (6.1%) died of unrelated causes. Of the 100 patients scanned using an MDCT scanner, one (1.0%) had a subsequent nonfatal PE 2 months after the initial scanning, one (1.0%) had DVT 1 month after the initial scanning, and eight (8.0%) died of unrelated causes. No significant difference was found in either the probability of subsequent thromboembolic events (chi(2) = 0.3183, degrees of freedom [df] = 1, p = 1) or frequency of unrelated deaths (chi(2) = 0.2655, df = 1, p = 0.7829) between patients scanned using single-detector CT or MDCT protocols.
  
  
  CONCLUSIONS
  Our results show that patients with suspected acute PE and negative CT results have acceptable clinical outcomes in the absence of anticoagulation treatment up to 6 months after acquisition of their initial scan. Furthermore, we found that the increased visualization of smaller, more peripheral arteries afforded by multislice technology did not affect clinical outcome.
authors.affiliation: Department of Radiology, University Hospitals of Cleveland, 11100 Euclid Ave., Cleveland, OH 44106, USA. jdprologo@hotmail.com
authors.forename: John David
authors.initials: JD
authors.lastname: Prologo
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gilkeson
authors.forename: Mireya
authors.initials: M
authors.lastname: Diaz
authors.forename: Matthew
authors.initials: M
authors.lastname: Cummings
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D000925:Anticoagulants / Q000627:therapeutic use; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000188:drug therapy; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D003287:Contrast Media; D007472:Iohexol