扩散加权磁共振成像在急性腔隙性脑梗死诊断中的敏感性

Lai P H, Li J Y, Chang C Y, Wu M T, Lo Y K, Chung P C

Department of Radiology, Veterans General Hospital-Kaohsiung, National Yang-Ming College, 386 Ta-Chung First Road, Kaohsiung, Taiwan.

J Formos Med Assoc. 2001 Jun;100(6):370-6.

BACKGROUND AND PURPOSE

Heightened interest in the early diagnosis and treatment of acute stroke challenges neuroimaging specialists to optimize available modalities and to develop new techniques for the evaluation of cerebrovascular disease. The purpose of this study was to evaluate the sensitivity of diffusion-weighted (DW) magnetic resonance (MR) imaging in detecting early small infarcts and in differentiating acute from nonacute small infarcts when conventional MR imaging demonstrates multiple small infarcts.

METHODS

Thirty-eight consecutive patients with a clinical diagnosis of lacunar infarcts (20 men and 18 women, aged 50-79 yr) who underwent DW MR imaging within 3 days of symptom onset were enrolled in this study. All patients underwent both conventional fast spin-echo (FSE) MR imaging and DW MR imaging. Apparent diffusion coefficient (ADC) maps were also acquired. All patients had at least one of the following classic lacunar syndromes: pure motor hemiparesis, ataxic hemiparesis, dysarthria-clumsy hand, pure sensory stroke, and sensorimotor stroke.

RESULTS

Thirty-six patients (40 acute lesions) had focal areas of high intensity on DW MR imaging associated with their clinical symptoms. Acute lacunar infarcts were seen on DW MR imaging as bright areas of decreased ADC ratio (range 0.31-0.85, mean 0.64). Lesion conspicuity with DW MR imaging was superior to that with FSE in 33 acute lesions. In four patients with small hyperacute (within 6 hours) infarcts, DW MR imaging was particularly sensitive for infarcts that were not visible on FSE sequences. The sensitivity of DW MR imaging and ADC map for acute lacunar infarcts was 95%, specificity 94%, positive predictive value 97%, negative predictive value 90%, and accuracy 95%. In 15 patients with both acute and nonacute old small infarcts, DW MR imaging and ADC map could easily distinguish the new infarct from adjacent old ones, although this distinction was difficult to make with FSE.

CONCLUSIONS

DW MR imaging accompanied by ADC map is a sensitive diagnostic modality for hyperacute and acute lacunar infarcts. It is also sensitive in distinguishing fresh small infarcts from adjacent multiple old infarcts.

背景与目的

对急性卒中早期诊断和治疗的关注度不断提高，这就要求神经影像专家优化现有检查方法，并开发评估脑血管疾病的新技术。本研究的目的是评估扩散加权（DW）磁共振（MR）成像在检测早期小梗死灶以及在传统MR成像显示多个小梗死灶时鉴别急性与非急性小梗死灶方面的敏感性。

方法

本研究纳入了38例临床诊断为腔隙性梗死的连续患者（20例男性和18例女性，年龄50 - 79岁），这些患者在症状发作后3天内接受了DW MR成像检查。所有患者均接受了传统快速自旋回波（FSE）MR成像和DW MR成像检查。还获取了表观扩散系数（ADC）图。所有患者至少有一种以下典型的腔隙综合征：纯运动性偏瘫、共济失调性偏瘫、构音障碍 - 笨拙手综合征、纯感觉性卒中以及感觉运动性卒中。

结果

36例患者（40个急性病灶）在DW MR成像上有与临床症状相关的局灶性高强度区域。急性腔隙性梗死在DW MR成像上表现为ADC比值降低的明亮区域（范围0.31 - 0.85，平均0.64）。在33个急性病灶中，DW MR成像的病灶清晰度优于FSE。在4例超急性（6小时内）小梗死灶患者中，DW MR成像对FSE序列上不可见的梗死灶特别敏感。DW MR成像和ADC图对急性腔隙性梗死的敏感性为95%，特异性为94%，阳性预测值为97%，阴性预测值为90%，准确性为95%。在15例既有急性又有非急性陈旧性小梗死灶的患者中，DW MR成像和ADC图能够轻松地将新梗死灶与相邻的陈旧梗死灶区分开来，尽管用FSE很难做到这一点。