Abstract 14144: Reproducibility of Myocardial Blood Flow Quantification With Low-Dose CT

Abstract

Introduction: Dynamic CT perfusion can be used for physiological assessment of coronary artery disease. However, it is limited by its high radiation dose and limited reproducibility. Hypothesis: A single-volume myocardial CT perfusion technique can reproducibly measure myocardial blood flow in mL/min/g at a low radiation dose. Methods: The reproducibility of a single-volume myocardial CT perfusion technique was assessed in 4 swine (54.5 ± 1.9 kg) under rest and stress (IV adenosine: 240 μg/mg/kg/min) conditions. Thirteen pairs of repeated CT measurements were made, with a 20-minute delay between each acquisition. Contrast (0.7 mL/kg; 370 mgI/mL) and saline chaser (0.35 mL/kg) were injected peripherally, each at 5 mL/s, followed by bolus tracking and acquisition of a single volume scan at 100 kVp and 200 mA with a 320-slice CT scanner. The timing for acquisition of the single volume scan was determined based on the contrast injection time. The bolus tracking and single volume scan data were then used as analytical inputs into a novel first-pass analysis model to derive perfusion in mL/min/g. The coronary artery centerlines from the volume scan were used for automatic assignment of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA) perfusion territories. The reproducibility of myocardial blood flow measurement in each territory was then assessed via regression analysis. Results: The first (P PRO1 ) and second (P PRO2 ) prospective single-volume CT perfusion measurements were related by P PRO2 = 1.04 P PRO1 - 0.05 (Pearson’s r = 0.99; RMSE = 0.24 mL/min/g). The average CT dose index of the technique was only 140.3 mGy. Conclusions: The single-volume quantitative CT perfusion technique provides low-dose, reproducible, myocardial perfusion measurement in mL/min/g using only bolus tracking data and a single whole-heart volume scan. The technique can also provide simultaneous CT angiogram when acquired with appropriate radiation dose.