Rivers Carly S, Wardlaw Joanna M, Armitage Paul A, Bastin Mark E, Carpenter Trevor K, Cvoro Vera, Hand Peter J, Dennis Martin S
Division of Clinical Neurosciences, Western General Hospital, Edinburgh, UK.
Stroke. 2006 Jun;37(6):1418-23. doi: 10.1161/01.STR.0000221294.90068.c4. Epub 2006 Apr 27.
Some infarcts have persistently hyperintense areas on diffusion-weighted MRI (DWI) even at 1 month after stroke, whereas others have become isointense to normal brain. We hypothesized that late DWI hyperintensity reflected different infarct evolution compared with areas that were isointense by 1 month.
We recruited patients prospectively with ischemic stroke, performed DWI and perfusion-weighted MRI (PWI) on admission, at 5 days, 14 days, and 1 month after stroke, and assessed functional outcome at 3 months (Rankin Scale). Patient characteristics and DWI/PWI values were compared for patients with or without "still hyperintense" infarct areas on 1-month DWI.
Among 42 patients, 27 (64%) had "still hyperintense" infarct regions at 1 month, mostly in white matter. Patients with "still hyperintense" regions at 1 month had lower baseline apparent diffusion coefficient ratio (ADCr; mean+/-SD 0.76+/-0.12 versus 0.85+/-0.12; hyperintense versus isointense; P<0.05), prolonged reduction of ADCr (repeated-measures ANOVA; P<0.01), no difference in baseline perfusion but delayed normalization of mean transit time (P<0.05) and cerebral blood flow ratios (repeated measures ANOVA; P<0.05), initially more severe stroke, and worse 3-month outcome than patients whose lesions were isointense by 1 month.
The late DWI lesion hyperintensity emphasizes the heterogeneity in temporal evolution of stroke injury and suggests ongoing "ischemia." Lower baseline ADCr precedes delayed perfusion normalization, suggesting that worse cell swelling impedes reperfusion. Further study is required to determine underlying mechanisms and any potential for subacute intervention to improve recovery.
部分梗死灶在卒中后1个月时，其扩散加权磁共振成像（DWI）上仍存在持续的高信号区域，而其他梗死灶则已与正常脑组织呈等信号。我们推测，与1个月时呈等信号的区域相比，晚期DWI高信号反映了不同的梗死演变过程。
我们前瞻性招募了缺血性卒中患者，在入院时、卒中后5天、14天和1个月进行DWI及灌注加权磁共振成像（PWI）检查，并在3个月时评估功能转归（Rankin量表）。比较1个月时DWI上有无“仍为高信号”梗死灶区域的患者的特征及DWI/PWI值。
42例患者中，27例（64%）在1个月时存在“仍为高信号”的梗死区域，主要位于白质。1个月时存在“仍为高信号”区域的患者基线表观扩散系数比值（ADCr；平均值±标准差为0.76±0.12对0.85±0.12；高信号对等信号；P<0.05）较低，ADCr降低持续时间延长（重复测量方差分析；P<0.01），基线灌注无差异，但平均通过时间延迟恢复正常（P<"0.05）及脑血流比值（重复测量方差分析；P<0.05），初始卒中更严重，且3个月时的转归比1个月时病灶呈等信号的患者更差。
晚期DWI病灶高信号凸显了卒中损伤时间演变的异质性，并提示存在持续的“缺血”。较低的基线ADCr先于灌注延迟恢复正常，提示更严重的细胞肿胀阻碍了再灌注。需要进一步研究以确定潜在机制以及亚急性干预改善恢复的任何可能性。
