Abstract 14754: Detection of Significant Stenosis in Left Anterior Descending Branch on Conventional Coronary Angiogram by Virtual “Myocardial Perfusion” Bolus Tracking CT Images in Coronary 320 Slice CT Angiography
Purpose: Diagnostic accuracy of coronary CT angiography is impaired by severe coronary calcification and surrogate measurements without additional radiation exposure are needed. We used bolus tracking CT images, which are usually used only to detect contrast material in target organs for optimal starting of acquisition, as virtual first pass myocardial perfusion images.
Methods: Retrospective analysis of 17 subjects (13 male, 62 ± 10 yrs) who were diagnosed with only >75% stenosis of left anterior descending branch (LAD) or non significant stenosis of any coronary arteries on conventional coronary angiogram (CAG) and underwent enhanced 320 slice CT and CAG within 2 months without incident. In CT, bolus tracking images were acquired at mid level of left ventricle (LV) with 120kV and 50mA until CT values of descending aorta increased to 200HU (mean DLP was 25 mGy cm). We measured CT values (HU) of LV anterior wall (AW), basal inter ventricular septum (BIVS) and LV basal lateral wall (BLW) in end systole (ES), and LV AW thickness in ES and end diastole (ED), and qualitatively assessed abnormal LV
AW motion and % decreases in CT values of LV AW compared with BIVS or LV BLW.
Results: 10 subjects revealed only LAD stenosis (Group 1) and 7 revealed no stenoses in any vessels (Group 2) on CAG.
CT values of LV AW, BIVS, and LV BLW, and ratio of CT values of LV AW to average of BIVS and LV BLW were 34 ± 15, 74 ± 17, 50 ± 19, and 0.5 ± 0.2 in Group1, and 56 ± 16, 63 ± 19, 57 ± 10, and 0.9 ± 0.2 in Group 2, respectively. CT values of LV AW and ratio of CT values of LV AW to average of BIVS and LV BLW were significantly lower in Group 1 (both P < 0.05). There were no significant differences in LV AW thickness in ES and ED, qualitative evaluation of LV AW motion, % decreases in CT values of LV AW compared with BIVS or LV
BLW, between the groups.
Conclusions: Bolus tracking CT images, which are usually not retained in clinical practice, may be useful to detect LAD stenosis by quantitative decreases in CT values of LV AW compared with BIVS and LV BLW.
- © 2013 by American Heart Association, Inc.