van Everdingen K J, van der Grond J, Kappelle L J, Ramos L M, Mali W P
Department of Radiology, University Hospital Utrecht, The Netherlands.
Stroke. 1998 Sep;29(9):1783-90. doi: 10.1161/01.str.29.9.1783.
Diffusion-weighted MRI (DWI) is highly sensitive in detecting early cerebral ischemic changes in acute stroke patients. In this study we compared the sensitivity of DWI with that of conventional MRI techniques. Furthermore, we investigated the prognostic value of the volume of ischemic lesions on DWI scans and of the apparent diffusion coefficient (ADC).
We performed DWI, fluid-attenuated inversion recovery, spin-echo T2-weighted MRI, and spin-echo proton density-weighted MRI in 42 patients with acute stroke and 15 control subjects. The volume of ischemic lesions was measured on early (<60 hours after onset) and follow-up MRI scans. Clinical outcome was measured 4 months after onset of symptoms with the National Institutes of Health Stroke Scale, the Barthel Index, and the Rankin Scale.
With DWI, 98% of the ischemic lesions were detected, and with fluid-attenuated inversion recovery, 91% were detected, whereas with early T2-weighted or proton density-weighted scans, only 71% (P=0.002, chi2) and 80% (P=0.02, chi2) of lesions, respectively, were found. Lesion volume on early DWI scans correlated significantly with clinical outcome ratings (P<0.01). In patients with a first-ever stroke, a lesion volume of < or =22 mL on DWI predicted good outcome with a 75% sensitivity and a 100% specificity. The mean ADC of ischemic lesions was 29% lower than the ADC of normal-appearing parts of the brain (P<0.001). The ADC ratio correlated significantly with clinical outcome (P<0.05).
DWI is a better imaging method than conventional MRI in detecting early ischemic lesions in stroke patients. Lesion size as measured on DWI scans and, to a lesser extent, ADC values are potential parameters for predicting clinical outcome in acute stroke patients.
扩散加权磁共振成像（DWI）在检测急性卒中患者早期脑缺血改变方面具有高度敏感性。在本研究中，我们比较了DWI与传统磁共振成像技术的敏感性。此外，我们还研究了DWI扫描上缺血性病变体积及表观扩散系数（ADC）的预后价值。
我们对42例急性卒中患者和15名对照者进行了DWI、液体衰减反转恢复序列、自旋回波T2加权磁共振成像及自旋回波质子密度加权磁共振成像检查。在发病早期（发病后<60小时）及随访磁共振成像扫描时测量缺血性病变体积。在症状发作4个月后，使用美国国立卫生研究院卒中量表、巴氏指数和Rankin量表评估临床结局。
通过DWI检测到98%的缺血性病变，通过液体衰减反转恢复序列检测到91%，而早期T2加权或质子密度加权扫描分别仅发现71%（P=0.002，卡方检验）和80%（P=0.02，卡方检验）的病变。早期DWI扫描上病变体积与临床结局评分显著相关（P<0.01）。在首次发生卒中的患者中，DWI上病变体积≤22 mL预测良好结局的敏感性为75%，特异性为100%。缺血性病变的平均ADC比脑外观正常部位的ADC低29%（P<0.001）。ADC比值与临床结局显著相关（P<0.05）。
在检测卒中患者早期缺血性病变方面，DWI是比传统磁共振成像更好的成像方法。DWI扫描测量的病变大小以及在较小程度上的ADC值是预测急性卒中患者临床结局的潜在参数。
