Yang Q, Tress B M, Barber P A, Desmond P M, Darby D G, Gerraty R P, Li T, Davis S M
Department of Radiology, Royal Melbourne Hospital and University of Melbourne, Victoria, Australia.
Stroke. 1999 Nov;30(11):2382-90. doi: 10.1161/01.str.30.11.2382.
We sought to characterize the evolution of apparent diffusion coefficient (ADC) and apparent diffusion anisotropy (ADA) in acute stroke and to evaluate their roles in predicting stroke evolution and outcome.
We studied 26 stroke patients acutely (<24 hours), subacutely (3 to 5 days), and at outcome (3 months). Ratios of the ADC and ADA within a region of infarction and the normal contralateral region were evaluated and compared with the Canadian Neurological Scale, Barthel Index, and Rankin Scale.
Heterogeneity in ADC and ADA evolution was observed not only between patients but also within individual lesions. Three patterns of ADA evolution were observed: (1) elevated ADA acutely and subacutely; (2) elevated ADA acutely and reduced ADA subacutely; and (3) reduced ADA acutely and subacutely. At outcome, reduced ADA with elevated ADC was observed generally. We identified 3 phases of diffusion abnormalities: (1) reduced ADC and elevated ADA; (2) reduced ADC and reduced ADA; and (3) elevated ADC and reduced ADA. The ADA ratios within 12 hours correlated with the acute Canadian Neurological Scale (r=0.46, P=0.06), subacute Canadian Neurological Scale (r=0.55, P=0.02), outcome Barthel Index (r=0.62, P=0.01), and Rankin Scale (r=-0.77, P<0.0005) scores.
Combined ADC and ADA provide differential patterns of stroke evolution. Early ADA changes reflect cellular alterations in acute ischemia and may provide a potential marker to predict stroke outcome.
我们试图描述急性卒中表观扩散系数（ADC）和表观扩散各向异性（ADA）的演变过程，并评估它们在预测卒中演变及预后方面的作用。
我们对26例卒中患者进行了急性期（<24小时）、亚急性期（3至5天）及预后（3个月）的研究。评估梗死区域与对侧正常区域内ADC和ADA的比值，并与加拿大神经功能量表、巴氏指数及Rankin量表进行比较。
不仅在患者之间，而且在单个病灶内均观察到ADC和ADA演变的异质性。观察到ADA演变的三种模式：（1）急性期和亚急性期ADA升高；（2）急性期ADA升高而亚急性期ADA降低；（3）急性期和亚急性期ADA降低。在预后时，通常观察到ADA降低而ADC升高。我们确定了扩散异常的三个阶段：（1）ADC降低而ADA升高；（2）ADC降低且ADA降低；（3）ADC升高且ADA降低。12小时内的ADA比值与急性期加拿大神经功能量表（r = 0.46，P = 0.06）、亚急性期加拿大神经功能量表（r = 0.55，P = 0.02）、预后巴氏指数（r = 0.62，P = 0.01）及Rankin量表（r = -0.77，P < 0.0005）评分相关。
联合使用ADC和ADA可提供不同的卒中演变模式。早期ADA变化反映急性缺血时的细胞改变，并可能为预测卒中预后提供潜在标志物。
