Abolition of Respiratory-Motion Artifact in Computed Tomography Coronary Angiography with Ultrafast Examinations: A Comparison Between 64-row and 320-row Multidetector Scanners

Purpose: To compare the incidence of respiratory artifact in computed tomography (CT) coronary angiography performed with 64-row and 320-row multidetector scanners and to assess its effect on coronary evaluability. Methods: A retrospective review of consecutive coronary angiograms performed on a 64-row multidetector CT from March to April 2007 (group 1: 115 patients, 63 men; mean age [standard deviation] 59.6 +/- 12.8 years) and on a 320-row multidetector CT from March to April 2008 (group 2: 169 patients, 89 men; mean [SD] age 57.9 +/- 11.6 years). Two cardiac radiologists assessed the occurrence of respiratory artifact and coronary evaluability in studies with respiratory artifacts. Unevaluable coronary segments because of motion at the same anatomical level of the respiratory artifact were considered unevaluable because of this artifact. The association between the occurrence of respiratory artifact and patient biometrics, medication, and scan parameters was examined. Results: Respiratory artifacts were detected in 9 of the 115 patients from group 1 (7.8%) and in none of the 169 patients from group 2 (P < .001). Group 1 had longer scan times (median, 9.3 seconds; range, 7.5-14.4 seconds) compared with group 2 (median, 1.5 seconds; range, 1.1-3.5 seconds; P < .001). In group 1, 4 patients (3.5%) showed unevaluable coronary segments because of respiratory artifacts, and the CT coronary angiography was repeated in 1 patient (0.9%). Conclusions: Respiratory artifacts are important in CT coronary angiography performed with 64-row multidetector scanners and impair the diagnostic utility of the examination in up to 3.5% of the studies. These artifacts can be virtually eliminated with a faster scan time provided by 320-row multidetector CT.