Low-dose quantitative CT myocardial flow measurement using a single volume scan: phantom and animal validation

To validate a low-dose, single-volume quantitative CT myocardial flow technique in a cardiovascular flow phantom and a swine animal model of coronary artery disease.A cardiovascular flow phantom was imaged dynamically over different flow rates (0.97 to 2.45 mL/min/g) using 15 mL of contrast per injection. Six swine (37±8 kg) were also imaged dynamically, with different left anterior descending coronary artery balloon stenoses assessed under intracoronary adenosine stress, using 1 mL/kg of contrast per injection. The resulting images were used to simulate dynamic bolus tracking and peak volume scan acquisition. After which, first-pass single-compartment modeling was performed to derive quantitative flow, where the pre-contrast myocardial attenuation was assumed to be spatially uniform. The accuracy of CT flow was then assessed versus ultrasound and microsphere flow in the phantom and animal models, respectively, using regression analysis.Single-volume quantitative CT flow measurements in the phantom (QCT_PHANTOM) were related to reference ultrasound flow measurements (QUS) by QCT_PHANTOM=1.04QUS-0.1 (Pearson's r=0.98; RMSE=0.09 mL/min/g). In the animal model (QCT_ANIMAL), they were related to reference microsphere flow measurements (QMICRO) by QCT_ANIMAL=1.00QMICRO-0.05 (Pearson's r=0.96; RMSE=0.48 mL/min/g). The effective dose per CT measurement was 1.21 mSv.The single-volume quantitative CT flow technique only requires bolus tracking data, spatially uniform pre-contrast myocardial attenuation, and a single volume scan acquired near the peak aortic enhancement for accurate, low-dose, myocardial flow measurement (in mL/min/g) under rest and adenosine stress conditions.