Schaefer Pamela W, Hassankhani Alvand, Putman Christopher, Sorensen A Gregory, Schwamm Lee, Koroshetz Walter, Gonzalez R Gilberto
Department of Radiology, Division of Neuroradiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
AJNR Am J Neuroradiol. 2004 Jun-Jul;25(6):951-7.
Lesions revealed by pretreatment diffusion-weighted imaging (DWI) may not progress to infarction, and apparent diffusion coefficient (ADC) or DWI thresholds for tissue viability may exist. We evaluated the evolution of abnormal DWI findings in patients with acute stroke who underwent thrombolysis.
Sixteen patients with acute occlusion of the anterior circulation underwent DWI followed by intra-arterial thrombolysis; follow-up CT or MR imaging was performed after reperfusion therapy. Lesion volumes were measured on all images. In three patients with abnormal DWI findings that appeared normal at follow-up, ADC values, ADC ratios, and DWI ratios were obtained on a section-by-section basis in the DWI-hyperintense regions that were either abnormal or normal at follow-up.
In three patients, part of the DWI-hyperintense tissue appeared normal and part appeared abnormal at follow-up imaging. In one of these patients, the lesion decreased by -35.6%. In the other two, lesion growth appeared in regions that appeared normal at initial DWI: in one, the overall change in size was -2.4%, and in the other, the lesion increased by 89.8%. Respective mean changes at follow-up in normal-appearing and abnormal-appearing regions were: ADC, 731.7 x 10(-6) mm(2)/s and 650.4 x 10(-6) mm (2)/s; ADC ratio, 0.92 and 0.78; and DWI ratio, 1.16 and 1.32 (P <.001 for all measures).
In patients with acute stroke who undergo intra-arterial thrombolysis, most abnormal, pretreatment DWI findings indicate eventual infarction. In 19% of the patients described herein, DWI-hyperintense regions appeared normal at follow-up. ADC values, ADC ratios, and DWI ratios may be useful in identifying the portion of abnormal tissue that is potentially salvageable after reperfusion therapy.
治疗前弥散加权成像（DWI）显示的病灶可能不会进展为梗死，可能存在组织存活的表观扩散系数（ADC）或DWI阈值。我们评估了接受溶栓治疗的急性卒中患者异常DWI表现的演变情况。
16例前循环急性闭塞患者接受DWI检查，随后进行动脉内溶栓治疗；再灌注治疗后进行随访CT或MRI检查。在所有图像上测量病灶体积。在3例DWI表现异常但随访时显示正常的患者中，在随访时异常或正常的DWI高信号区域逐节获取ADC值、ADC比率和DWI比率。
3例患者中，部分DWI高信号组织在随访成像时显示正常，部分显示异常。其中1例患者病灶减少了-35.6%。另外2例患者中，病灶在初始DWI时显示正常的区域出现增大：1例患者大小的总体变化为-2.4%，另1例患者病灶增大了89.8%。随访时正常和异常区域的平均变化分别为：ADC，731.7×10⁻⁶mm²/s和650.4×10⁻⁶mm²/s；ADC比率，0.92和0.78；DWI比率，1.16和1.32（所有测量指标P<0.001）。
在接受动脉内溶栓治疗的急性卒中患者中，大多数治疗前异常的DWI表现提示最终会发生梗死。在本文所述的19%的患者中，DWI高信号区域在随访时显示正常。ADC值、ADC比率和DWI比率可能有助于识别再灌注治疗后可能可挽救的异常组织部分。
