Abstract 2203: “One-Beat Whole Heart Coronary CT-Angiography” Using the 256-Multislice CT
PURPOSE: Since the 2nd spec 256-detector row computed tomography (256CT) covers 12.8 cm along z-axis (0.5mm slice thickness x 256-slice), it covers whole heart within one rotation (0.5 sec). The aim of this study was to assess the feasibility of “one-beat whole heart imaging” using the 2nd spec 256CT could evaluate simultaneous assessment of coronary artery and cardiac function in a clinical setting.
METHOD AND MATERIALS: Clinical materials consisted of 9 patients with old myocardial infarction (n = 3) and angina pectoris (n = 6), including 2 patients with atrial fibrillation. Seven patients of them received invasive coronary angiography (CAG). The procedure of “one-beat whole heart imaging” was as follows. After test injection of contrast medium for optimal scan timing, the scan was obtained without ECG-gating and table movement, using the contrast medium at 3 to 4 ml/sec (40 – 60 ml) with a chaser of saline at 3 ml/sec (20 ml). Acquisition time was 1.5 sec (one beat + fan angle [0.5 sec]). Parameters used were 0.5 mm slice thickness, 0.5 sec/rotation, 120 Kv and 350 mA (radiation exposure: 14.2 mSv), with half scan reconstruction algorithm (temporal resolution: 250msec). Twenty phases were extracted for coronary imaging and for 2D/3D cine (= 4D) cardiac imaging to assess cardiac function. In the most stable phase, coronary arteries were evaluated. Left ventricular functional parameters and volume curve including end-diastolic and end-systolic volumes, and ejection fraction were obtained.
RESULTS: In all subjects, coronary arteries were assessable without stair-step artifacts. The assessability of CT-angiography (CTA) was 83 % (113/136) in total. The reasons for the un-assessable coronary segment were small vessel (< 1.5mm, n = 11), calcification (n = 8) and coronary stent (n = 4). The overall sensitivity, Specificity, and positive and negative predictive value for the presence of significant stenoses (> 70% by CAG)were: by segment (n = 106), 100%, 95%, 71% and 100%, respectively. All left ventricular functional parameters were abnormality in the infarcted lesions could be assessed.
CONCLUSION: The 2nd spec 256CT seems to be a promising next generation CT for the robust coronary and cardiac imaging, allowing “One-beat whole heart imaging”.