Department of Medical Imaging, University of Toronto, 150 College Street, Toronto, Ontario, Canada.
AJNR Am J Neuroradiol. 2010 Jun;31(6):1015-22. doi: 10.3174/ajnr.A2003. Epub 2010 Feb 25.
rtPA is an effective treatment for AIS, yet it is substantially underused due to the increased risk of HT. Recent work suggests that permeability-related information can be extracted from routine T2*-based perfusion images by measuring the rR of the contrast agent. Given that other T2*-based measures have recently been proposed, the purpose of this study was to evaluate 4 such permeability measures in identifying patients with AIS who will proceed to HT.
Eighteen patients with AIS were examined within a mean of 3.3 +/- 1.4 hours postonset. Dynamic T2*-weighted imaging consisted of a single-shot EPI following a bolus of gadodiamide. HT was determined on follow-up CT or MR imaging at 24-72 hours. Mean values of rR, Peak Height, Recovery, as well as Slope were calculated and analyzed on the basis of follow-up HT status.
Eight patients proceeded to HT. The mean rR for patients with HT was significantly greater than that for patients without HT (0.22 +/- 0.06 versus 0.14 +/- 0.06, P = .006), while there was a trend toward decreased %Recovery in patients with HT (76 +/- 6 versus 82 +/- 11%, P = .092). There was a significant negative correlation between %Recovery and rR (r = -0.88, P < .001). No significant differences or trends were detected with respect to Peak Height or Slope.
Both rR and %Recovery can be readily extracted from a routine perfusion MR imaging dataset and show potential for identifying HT during the acute phase poststroke.
rtPA 是治疗急性缺血性脑卒中（AIS）的有效方法，但由于增加了发生高血压（HT）的风险，其使用受到了很大限制。最近的研究表明，通过测量对比剂的 rR，可以从常规基于 T2的灌注图像中提取与通透性相关的信息。鉴于最近已经提出了其他基于 T2的测量方法，本研究旨在评估 4 种此类通透性测量方法在识别将进展为 HT 的 AIS 患者中的作用。
18 例 AIS 患者在发病后平均 3.3±1.4 小时内进行了检查。动态 T2*-加权成像采用单次激发 EPI 序列，在注射钆喷酸葡胺造影剂后进行。HT 通过 24-72 小时的随访 CT 或 MR 成像来确定。根据随访 HT 状态，计算并分析 rR、峰值高度、恢复率以及斜率的平均值。
8 例患者进展为 HT。HT 患者的 rR 均值明显大于无 HT 患者（0.22±0.06 比 0.14±0.06，P=0.006），而 HT 患者的 %Recovery 呈下降趋势（76±6 比 82±11%，P=0.092）。%Recovery 与 rR 之间存在显著的负相关（r=-0.88，P<0.001）。与 rR 相比，峰值高度和斜率无明显差异或趋势。
rR 和 %Recovery 均可从常规灌注 MR 成像数据集中轻松提取，并有可能在卒中后急性期识别 HT。
