Association of Contrast Medium Arrival Time with Conventional Risk Factors and Morise Score in Detecting Obstructive Coronary Artery Disease

 Association of Contrast Medium Arrival Time with Conventional Risk Factors and Morise Score in Detecting Obstructive Coronary Artery Disease

Objectives: To determine the association of contrast medium arrival time during coronary CT angiography with the conventional coronary risk factors and Morise score in detecting obstructive CAD. Materials and Methods: A total of 665 patients were retrospectively included in the study. Contrast medium arrival time was recorded as the time from the start of the injection to the threshold of 100 HU at the descending aorta during the bolus tracking scan. The Morise score was calculated for each patient and modified Morise score (MMS) was defined as Morise score*heart rate*arrival time/1000. Anatomically obstructive CAD was determined as ≥50% stenosis by CT angiography. Results: Longer contrast medium arrival time was significantly related with obstructive CAD in multivariate analysis (p = 0.03). MMS improved the area under the curve from 0.59 to 0.63 (p = 0.01) with a net reclassification index of 0.14 compared with the Morise score in discriminating patients with obstructive CAD from those without. The presence of obstructive CAD of the 1st quartile of MMS was significantly lower compared with the remaining quartiles (vs 2nd quartile, p = 0.01; vs 3rd quartile, p = 0.002; vs 4th quartile, p < 0.0001). Conclusion: Longer contrast medium arrival time was related with obstructive CAD independent of conventional cardiovascular risk factors. MMS had an additive value over the Morise model alone to predict obstructive CAD in coronary CT angiography.