Boos M, Scheffler K, Haselhorst R, Reese E, Fröhlich J, Bongartz G M
Department of Radiology, University-Hospital, Basel, Switzerland.
J Magn Reson Imaging. 2001 Apr;13(4):568-76. doi: 10.1002/jmri.1080.
This study was performed to evaluate the dynamics of an arterial first pass gadolinium (Gd) contrast medium (CM) bolus at the descending aorta (DAo), depending on various saline flush and Gd volumes. Using an ultra-fast two- dimensional GE-sequence (Siemens Vision, 1.5-T), 200 sequential cross-sectional images of the addressed vessel (1 slice/s) were obtained. Several saline flush volumes (15 mL, 30 mL, and 60 mL) were applied following the administration of 10 mL Gd (single dose) to a group of 4 normal volunteers (body weight 50-55 kg) using a mechanical MR injector (injection rate = 3.0 mL/s). Additionally, when performing a second test series, the saline volume remained constant, while the Gd volumes were varied from half doses to triple doses (5, 10, 20, and 30 mL Gd were given to every volunteer of the group). The signal intensity versus time (SI/T) curve at a measured region of interest (ROI) within the DAo was calculated. The bolus arrival time (BAT), the maximal signal-to-noise ratio (SNR(max)), the bolus time length (BL; 75% and 80% maximum intensity duration), the slope of the SI/T curve, and the areas below the SI/T curve for both the 80% and 75% maximum intensity duration level (INT(80%) and INT(75%)) were calculated. The increase of saline flush volume from 30 to 60 mL caused significant bolus lengthening of approximately 50% (mean BL = 9.5 s, 10.3 s, and 15.4 s for 15 mL, 30 mL, and 60 mL saline flush volumes, respectively, measured as SI/T duration at the 75% SNR(max) level). Using saline flush volumes equal to or higher than 30 mL increased the slope of the SI/T curve. A continuous increase of INT(75%/80%) by using higher saline flush volumes was found. Different saline and Gd volumes did not affect the SNR(max) and the BAT. Only the low dose (0.05 mmol/kg Gd) showed a 17%-21.6% significantly lower SNR(max). The BL and the INT increased mainly by enlarging of applied Gd volume from single to double dose (BL(75%) and INT(75%) were 9.6 s and 1305, 12.3 s and 2121, 38.5 s and 6181, 37.8 s and 6613 for 5, 10, 20, and 30 mL applied Gd volume, respectively). The arterial bolus length benefits from increasing Gd and saline flush volumes due to increased venous bolus length and wash out effects of Gd within the injection site of the vein. Doses larger than a single dose are not needed to increase the SNR in contrast-enhanced magnetic resonance angiography images of the thoracic aorta.
本研究旨在评估不同生理盐水冲洗量和钆（Gd）剂量情况下，降主动脉（DAo）处动脉首过钆对比剂（CM）团注的动力学情况。使用超快速二维GE序列（西门子Vision，1.5-T），获取所关注血管的200幅连续横断面图像（每秒1层）。对一组4名体重50 - 55千克的正常志愿者，使用机械MR注射器（注射速率 = 3.0 mL/s），在给予10 mL Gd（单剂量）后，应用几种不同的生理盐水冲洗量（15 mL、30 mL和60 mL）。此外，在进行第二个测试系列时，生理盐水冲洗量保持恒定，而Gd剂量从半剂量变化到三倍剂量（该组中的每位志愿者分别给予5、10、20和30 mL Gd）。计算DAo内测量感兴趣区域（ROI）处的信号强度与时间（SI/T）曲线。计算团注到达时间（BAT）、最大信噪比（SNR(max)）、团注持续时间（BL；最大强度持续时间的75%和80%）、SI/T曲线的斜率以及最大强度持续时间水平为80%和75%时SI/T曲线下的面积（INT(80%)和INT(75%)）。生理盐水冲洗量从30 mL增加到60 mL导致团注显著延长约50%（对于15 mL、30 mL和60 mL生理盐水冲洗量，平均BL分别为9.5 s、10.3 s和15.4 s，在75% SNR(max)水平下作为SI/T持续时间测量）。使用等于或高于30 mL的生理盐水冲洗量会增加SI/T曲线的斜率。发现使用更高的生理盐水冲洗量时，INT(75%/80%)持续增加。不同的生理盐水和Gd剂量不影响SNR(max)和BAT。只有低剂量（0.05 mmol/kg Gd）显示SNR(max)显著降低17% - 21.6%。BL和INT主要通过将应用的Gd剂量从单剂量增加到双剂量而增加（对于应用Gd剂量为5、10、20和30 mL，BL(75%)和INT(75%)分别为9.6 s和1305、12.3 s和2121、38.5 s和6181、37.8 s和为6613）。由于静脉团注长度增加以及Gd在静脉注射部位的洗脱效应，动脉团注长度受益于增加Gd和生理盐水冲洗量。在胸主动脉对比增强磁共振血管造影图像中，不需要大于单剂量的剂量来增加SNR。
