Fiehler Jens, Knudsen Karina, Kucinski Thomas, Kidwell Chelsea S, Alger Jeffry R, Thomalla Götz, Eckert Bernd, Wittkugel Oliver, Weiller Cornelius, Zeumer Hermann, Röther Joachim
Department of Neuroradiology, University Hospital Eppendorf, University of Hamburg, Hamburg, Germany.
Stroke. 2004 Feb;35(2):514-9. doi: 10.1161/01.STR.0000114873.28023.C2. Epub 2004 Jan 22.
We sought to describe the frequency of normalization of apparent diffusion coefficient (ADC) values that are decreased in hyperacute stroke and to identify characteristics of tissue demonstrating normalization.
Sixty-eight acute ischemic stroke patients underwent MRI examination (including diffusion/perfusion imaging and MR angiography) within 6 hours (mean, 2.8 hours) after symptom onset, after 24 hours, and again 4 to 7 days later. Lesion volumes with decreased ADC and delayed time to peak in perfusion imaging were determined. In patients showing ADC normalization, volumes with ADC decrease graded as <50%, 50% to 60%, 60% to 70%, and 70% to 80% of the contralateral value were determined by thresholding. Patients were categorized as normalizers (demonstrating ADC normalization in >5 mL tissue with initially decreased ADC) or nonnormalizers (demonstrating ADC normalization in <5 mL tissue).
Fourteen patients (19.7%) were classified as normalizers. Eleven of 31 patients (35.5%) initially imaged <3 hours after stroke onset and 3 of 37 (7.5%) of those imaged 3 to 6 hours after onset were normalizers. ADC normalization occurred predominantly in the basal ganglia and white matter after thrombolytic therapy in patients with more distal vessel occlusions. All normalizers demonstrated at least partial tissue reperfusion. Tissue with more severe initial decrease in ADC was less likely to demonstrate normalization.
ADC normalization is not a rare event in acute stroke after tissue reperfusion. Brain tissue with initially decreased ADC, especially within 3 hours after stroke onset, may include "tissue at risk."
我们试图描述超急性卒中时降低的表观扩散系数（ADC）值恢复正常的频率，并确定显示正常化的组织特征。
68例急性缺血性卒中患者在症状发作后6小时内（平均2.8小时）、24小时后以及4至7天后接受了MRI检查（包括弥散/灌注成像和磁共振血管造影）。确定ADC降低且灌注成像中达峰时间延迟的病变体积。在显示ADC正常化的患者中，通过阈值确定ADC降低程度分级为对侧值<50%、50%至60%、60%至70%以及70%至80%的体积。患者被分为正常化者（初始ADC降低的>5 mL组织中显示ADC正常化）或非正常化者（<5 mL组织中显示ADC正常化）。
14例患者（19.7%）被分类为正常化者。31例卒中发作后<3小时进行初始成像的患者中有11例（35.5%）以及37例发作后3至6小时进行成像的患者中有3例（7.5%）为正常化者。在更远处血管闭塞的患者中，溶栓治疗后ADC正常化主要发生在基底节和白质。所有正常化者均显示至少部分组织再灌注。ADC初始降低更严重的组织显示正常化的可能性较小。
在组织再灌注后的急性卒中中，ADC正常化并非罕见事件。初始ADC降低的脑组织，尤其是卒中发作后3小时内，可能包括“危险组织”。
