Department of Neuroradiology, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany.
Clin Neuroradiol. 2012 Mar;22(1):29-37. doi: 10.1007/s00062-011-0126-x. Epub 2012 Jan 20.
Arterial spin labeling (ASL) is a promising but clinically not established non-invasive method to assess cerebral perfusion. The purpose of this study was to compare perfusion imaging with pulsed ASL (pASL) to conventional dynamic susceptibility contrast (DSC) perfusion-weighted imaging (PWL) using commercially available equipment and postprocessing (3.0 Tesla, 32-channel head coil) in patients with subacute ischemia.
The pASL and DSC-PWI techniques were compared in 15 patients with subacute ischemia (age 49-88 years, 6 females and 9 males, time from onset to scan 4-161 h). Image inhomogeneity was assessed with the non-uniformity index. Image quality, delineation of hypoperfusion and degree of hypoperfusion were rated by two readers using a 5-scale grading system. The volume of hypoperfusion was quantified planimetrically.
Image quality and image inhomogeneity were superior in DSC time-to-peak (TTP) compared to pASL cerebral brain flow (CBF; both p < 0.05). The delineation of hypoperfusion was better in DSC-TTP (p < 0.05) and the hypoperfusion was graded as more severe in DSC-TTP (p < 0.05). The volume of hypoperfusion did not differ between pASL-CBF and DSC-TTP, however, in pASL-CBF five cases with small infarctions (lacunar and pontine) were false negative compared to DSC-relative CBF. The mismatch frequency was lower in pASL (13%) than in DSC-rCBF (20%) and DSC-TTP (47%).
Using a commercially available sequence and a 32-channel head coil at 3.0 Tesla pASL-CBF is feasible but limited compared to DSC-PWI in the assessment of ischemic stroke. In its present form pASL has a reserve role in clinical practice for situations when gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) is contraindicated.
动脉自旋标记（ASL）是一种很有前途但尚未在临床上确立的非侵入性方法，可用于评估脑灌注。本研究的目的是比较使用商业上可获得的设备和后处理（3.0 特斯拉，32 通道头部线圈）的脉冲 ASL（pASL）与传统的动态对比磁共振成像（DSC）灌注加权成像（PWL）在亚急性缺血患者中的灌注成像。
比较了 15 例亚急性缺血患者（年龄 49-88 岁，女性 6 例，男性 9 例，发病至扫描时间 4-161 小时）的 pASL 和 DSC-PWI 技术。使用不均匀性指数评估图像不均匀性。两位读者使用 5 级评分系统评估图像质量、低灌注的描绘和低灌注的程度。通过平面测量定量评估低灌注的体积。
DSC 时间至峰值（TTP）的图像质量和图像不均匀性优于 pASL 脑血流量（CBF；均 p<0.05）。DSC-TTP 对低灌注的描绘更好（p<0.05），DSC-TTP 对低灌注的分级更严重（p<0.05）。pASL-CBF 和 DSC-TTP 之间的低灌注体积无差异，但在 pASL-CBF 中，与 DSC-相对 CBF 相比，5 例小梗死（腔隙性和桥脑）为假阴性。pASL 的失配频率（13%）低于 DSC-rCBF（20%）和 DSC-TTP（47%）。
在 3.0 特斯拉使用商业上可获得的序列和 32 通道头部线圈的 pASL-CBF 是可行的，但与 DSC-PWI 相比，在评估缺血性卒中方面存在局限性。在目前的形式下，pASL 在钆二乙三胺五乙酸（Gd-DTPA）禁忌的情况下，在临床实践中具有备用作用。
