Kumar Arun, Bis Kostaki G, Shetty Anil, Vyas Amit, Anderson Andrew, Balasubramaniam Mamtha, O'Neill William, Stein Wendy
Department of Diagnostic Radiology, William Beaumont Hospital, 3601 W 13 Mile Rd., Royal Oak, MI 48073, USA.
AJR Am J Roentgenol. 2007 May;188(5):W415-22. doi: 10.2214/AJR.06.0945.
The purpose of this study was to evaluate the minimum amount of contrast material for coronary imaging with aortic root catheter-directed enhancement and 64-MDCT angiography (MDCTA).
A 64-MDCT scanner was used after animal institutional review board approval to study four swine (40-60 kg). Heart rate reduction to 65 beats per minute was achieved with atenolol by mouth and i.v. Cardizem. Common femoral artery access was obtained with a 5-French micropuncture kit and sonographic guidance. A diffusiontip (640 side holes), 5-French pigtail catheter was positioned in the aortic root on the CT table with a retrofitted C-arm fluoroscopy unit and connected to an arterial power injector. Aortic root MDCTA (retrospective ECG gating; collimation, 0.6 mm; tube rotation time, 0.33 second; scanning time, 10-12 seconds; tube voltage, 120 kVp; effective mAs, 850 mAs; pitch, 0.2; field of view, 109-123 mm; slice thickness and increment, 0.6 and 0.3 mm) was begun 1 second after the injection of 100 mL of various Visipaque (iodixanol) concentrations (10%, 20%, 30%, 40%) at 10 mL/s. Coronary mean and peak densities, 3D maximum intensity projections, and 4D projections were obtained.
The mean pooled coronary attenuation values (H +/- SD) for the right (RCA), left anterior descending (LAD), and left circumflex (LCx) coronary arteries at various concentrations (10%, 20%, 30%, 40%) were as follows: 10% (RCA [232.6 +/- 64.0], LAD [180.4 +/- 45.1], and LCx [176.6 +/- 56.2]); 20% (RCA [383.0 +/- 98.7], LAD [324.3 +/- 60.1], and LCx [331.8 +/- 105.5]); 30% (RCA [441.8 +/- 137.6], LAD [401.3 +/- 125.8], and LCx [418.5 +/- 173.0]); and 40% (RCA [717.3 +/- 377.7], LAD [573.3 +/- 233.3], and LCx [584.8 +/- 189.0]). Coronary imaging with aortic root MDCTA was feasible at all concentrations, and the attenuation values were statistically significantly greater than 250 H at 20%, 30%, and 40% (p < 0.05). The attenuation values with aortic root MDCTA using one fifth of the volume of contrast material are comparable to those currently achieved both clinically and experimentally with peripheral i.v. MDCTA.
Aortic root MDCTA can depict the coronary arteries with as little as 20 mL of contrast material. This may provide an alternative means of coronary evaluation in patients with renal insufficiency.
本研究旨在评估经主动脉根部导管引导增强联合64层螺旋CT血管造影（MDCTA）进行冠状动脉成像所需的最小对比剂用量。
经动物机构审查委员会批准后，使用64层MDCT扫描仪对4头猪（40 - 60千克）进行研究。通过口服阿替洛尔和静脉注射地尔硫䓬将心率降至每分钟65次。采用5法国微穿刺套件并在超声引导下经股总动脉穿刺。在CT检查台上，使用改装后的C臂荧光透视装置将带有扩散头（640个侧孔）的5法国猪尾导管置于主动脉根部，并连接至动脉高压注射器。在以10 mL/s的速度注射100 mL不同浓度（10%、20%、30%、40%）的碘克沙醇（威视派克）后1秒开始进行主动脉根部MDCTA扫描（回顾性心电门控；准直0.6 mm；管旋转时间0.33秒；扫描时间10 - 12秒；管电压120 kVp；有效毫安秒850 mAs；螺距0.2；视野109 - 123 mm；层厚及层间距0.6和0.3 mm）。获取冠状动脉的平均密度和峰值密度、三维最大密度投影及四维投影。
不同浓度（10%、20%、30%、40%）下右冠状动脉（RCA）、左前降支（LAD）和左旋支（LCx）冠状动脉的平均合并衰减值（H±SD）如下：10%（RCA [232.6±64.0]，LAD [180.4±45.1]，LCx [176.6±56.2]）；20%（RCA [383.0±98.7]，LAD [324.3±60.1]，LCx [331.8±105.5]）；30%（RCA [441.8±137.6]，LAD [401.3±125.8]，LCx [418.5±173.0]）；40%（RCA [717.3±377.7]，LAD [573.3±233.3]，LCx [584.8±189.0]）。在所有浓度下，经主动脉根部MDCTA进行冠状动脉成像均可行，且在20%、30%和40%浓度时，衰减值在统计学上显著大于250 H（p < 0.05）。使用五分之一对比剂用量的主动脉根部MDCTA的衰减值与目前临床和实验中经外周静脉MDCTA所获得的衰减值相当。
主动脉根部MDCTA使用低至20 mL的对比剂即可显示冠状动脉。这可能为肾功能不全患者提供一种冠状动脉评估的替代方法。
