Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Ansin 242, Boston, MA 02215, USA.
Radiology. 2010 Nov;257(2):507-15. doi: 10.1148/radiol.092333.
To demonstrate an arterial spin-labeling (ASL) magnetic resonance (MR) angiographic technique that covers the entire cerebral vasculature and yields transparent-background, time-resolved hemodynamic, and vessel-specific information similar to that obtained with x-ray digital subtraction angiography (DSA) without the use of exogenous contrast agents.
Prior institutional review board approval and written informed consent were obtained for this HIPAA-compliant study in which 12 healthy volunteers (five women, seven men; age range, 21-62 years; average age, 28 years) underwent imaging. An ASL technique in which variable labeling durations are used to acquire hemodynamic inflow information and a vessel-selective pulsed-continuous ASL technique were tested. Region-of-interest signal intensities in various vessel segments were averaged across subjects and used to quantitatively compare images. For comparison, a standard time of flight (TOF) acquisition was performed in the circle of Willis.
Inflow temporal resolution of 200 msec was demonstrated, revealing arterial transit times of 750, 950, and 1100 msec to consecutive segments of the middle cerebral artery from distal to the circle of Willis to deep regions of the midbrain. Selective labeling resulted in an average of eightfold suppression of contralateral vessels relative to the labeled vessel. Signal-to-noise ratios and contrast-to-noise ratios on maximum intensity projection images obtained with 88-second volumetric acquisitions (60 ± 15 [standard deviation] and 57 ± 15, respectively) and 11-second single-projection acquisitions (19 ± 5 and 17 ± 5, respectively) were comparable with standard TOF acquisitions, in which a 2.7-fold longer imaging duration for a 2.6-fold lower pixel area was used. Normal variations of the vasculature were identified with ASL angiography.
ASL angiography can be used to acquire hemodynamic vessel-specific information similar to that obtained with x-ray DSA.
展示一种动脉自旋标记（ASL）磁共振（MR）血管造影技术，该技术可覆盖整个脑血管系统，并提供类似于 X 射线数字减影血管造影（DSA）的透明背景、时分辨的血流动力学和血管特异性信息，而无需使用外源性对比剂。
本研究符合 HIPAA 规定，经机构审查委员会批准并获得书面知情同意，12 名健康志愿者（5 名女性，7 名男性；年龄 21-62 岁，平均 28 岁）参与了此项研究。我们测试了一种 ASL 技术，该技术使用可变的标记持续时间来获取血流动力学流入信息和血管选择性脉冲连续 ASL 技术。在受试者之间平均各个血管节段的感兴趣区信号强度，并用于定量比较图像。为了比较，在 Willis 环中进行了标准的时间飞跃（TOF）采集。
证明了 200 msec 的流入时间分辨率，显示从 Willis 环到中脑深部的中间脑动脉的连续节段的动脉传输时间为 750、950 和 1100 msec。选择性标记导致相对于标记血管，对侧血管的平均抑制达到 8 倍。使用 88 秒容积采集（分别为 60 ± 15 [标准差]和 57 ± 15）和 11 秒单投影采集（分别为 19 ± 5 和 17 ± 5）获得的最大强度投影图像的信噪比和对比噪声比与标准 TOF 采集相当，其中使用了 2.7 倍长的成像时间和 2.6 倍低的像素面积。ASL 血管造影可以识别血管的正常变异。
ASL 血管造影可用于获取类似于 X 射线 DSA 的血流动力学血管特异性信息。
