Potthast Silke, Bongartz Georg M, Huegli Rolf, Schulte Anja-Carina, Schwarz Jochen G, Aschwanden Markus, Bilecen Deniz
Institute of Diagnostic Radiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
AJR Am J Roentgenol. 2007 Mar;188(3):823-9. doi: 10.2214/AJR.06.0520.
Repeated intraarterial gadolinium injections are necessary in endovascular MRI-guided interventions; therefore a low-dose protocol with a short acquisition time is preferable. The purpose of this study was to conduct a quantitative comparison of intraarterial MR aortograms obtained with and without high-speed parallel acquisition technique.
Intraarterial MR aortography was performed at 1.5 T on nine patients with peripheral arterial occlusive disease and in an aortic phantom with pulsatile flow. A 3D fast low-angle shot MRI sequence was used for standard technique (acquisition time, 20 seconds) and for parallel acquisition technique (acquisition time, 14 seconds). In all patients, a pigtail catheter was left in the suprarenal position after digital subtraction angiography. Contrast-enhanced intraarterial MR aortography was performed after automated injection of 50 mmol/L gadoterate dimeglumine at an injection rate of 4 mL/s. Contrast-to-noise ratio (CNR) and image quality were evaluated in both imaging series at different locations. In an aortic phantom with pulsatile flow, CNR was determined 1, 30, and 60 cm distal to the catheter tip with standard and parallel acquisition techniques.
In all patients, intraarterial MR aortography was feasible with both acquisition techniques. No significant difference in CNR or image quality was observed in the patient study. Similar results were calculated for the pulsatile aortic flow phantom at all locations.
Intraarterial MR aortography is feasible with parallel acquisition technique without a significant loss of CNR. This technique reduces contrast agent consumption approximately 30% owing to an approximately 30% reduction in acquisition time.
在血管内磁共振成像引导的介入操作中,需要多次动脉内注射钆造影剂;因此,采用低剂量方案且采集时间短更为可取。本研究的目的是对使用和不使用高速并行采集技术获得的动脉内磁共振主动脉造影进行定量比较。
对9例外周动脉闭塞性疾病患者以及一个具有搏动血流的主动脉模型进行了1.5T的动脉内磁共振主动脉造影。使用三维快速低角度激发磁共振成像序列进行标准技术(采集时间20秒)和并行采集技术(采集时间14秒)。在所有患者中,数字减影血管造影后将猪尾导管留置在肾上腺上方位置。以4mL/s的注射速率自动注射50mmol/L钆双胺后进行对比增强动脉内磁共振主动脉造影。在两个成像系列的不同位置评估对比噪声比(CNR)和图像质量。在具有搏动血流的主动脉模型中,使用标准和并行采集技术在导管尖端远端1、30和60cm处测定CNR。
在所有患者中,两种采集技术均可行进行动脉内磁共振主动脉造影。在患者研究中,未观察到CNR或图像质量有显著差异。在搏动性主动脉血流模型的所有位置计算得到了类似结果。
并行采集技术用于动脉内磁共振主动脉造影是可行的,且CNR无显著损失。由于采集时间减少约30%,该技术可使造影剂用量减少约30%。