Perkins C J, Kahya E, Roque C T, Roche P E, Newman G C
Department of Neurology, SUNY at Stony Brook, Stony Brook, NY, USA.
Stroke. 2001 Dec 1;32(12):2774-81. doi: 10.1161/hs1201.099634.
Diffusion-weighted MRI (DWI) is highly sensitive to early cerebral ischemia, but its dependence on lesion location, acuity, and etiology remains unknown. Furthermore, although a marked perfusion-weighted MRI (PWI)-DWI mismatch may exist in a subset of acute strokes, the frequency and distribution of these mismatches have never been methodically characterized in an unselected population. To address these 2 issues, we evaluated echo-planar imaging in 117 consecutive patients with signs and symptoms of acute stroke.
Clinical diagnoses were determined by chart review. Fluid-attenuated inversion recovery (FLAIR), DWI, and PWI sequences were scored for lesion acuity, neuroanatomy, and vascular territory. Lesion and PWI-DWI mismatch volumes were determined by image analysis.
DWI was more sensitive than was FLAIR for the detection of stroke for all subtypes in all anatomic distributions and at all tested time intervals. Although DWI exhibited its greatest benefit over FLAIR during the first 6 hours, it was still superior to FLAIR even after 24 hours. PWI abnormalities were detected in 49% of patients with DWI abnormalities. In the majority of these cases, the PWI-DWI mismatch was substantially larger than the DWI lesion itself. Both the largest DWI lesion volumes and the largest mismatch volumes occurred in patients with carotid disease.
DWI nearly doubles the likelihood of detecting acute ischemic stroke lesions compared with FLAIR for all etiologies and in all anatomic locations. In the hyperacute period (0 to 6 hours), DWI more than triples the likelihood of acute-stroke detection over FLAIR. PWI reveals a measurable mismatch compared with DWI nearly 50% of the time; and in more than half of these patients, the ratio of the volume of the PWI lesion to the DWI lesion is several times larger than the core ischemic lesion itself. In the final analysis, approximately one fourth of all stroke patients present with a large volume of potentially salvageable tissue at risk for infarction.
扩散加权磁共振成像（DWI）对早期脑缺血高度敏感，但其对病变位置、严重程度及病因的依赖性尚不清楚。此外，尽管在部分急性卒中患者中可能存在明显的灌注加权磁共振成像（PWI）-DWI不匹配，但这些不匹配的频率和分布在未经过筛选的人群中从未得到系统的描述。为解决这两个问题，我们对117例有急性卒中症状和体征的连续患者进行了回波平面成像评估。
通过查阅病历确定临床诊断。对液体衰减反转恢复（FLAIR）、DWI和PWI序列的病变严重程度、神经解剖结构及血管分布区域进行评分。通过图像分析确定病变及PWI-DWI不匹配体积。
在所有解剖分布的所有亚型以及所有测试时间间隔内，DWI在检测卒中方面比FLAIR更敏感。尽管DWI在最初6小时内相对于FLAIR显示出最大优势，但即使在24小时后仍优于FLAIR。在49%的DWI异常患者中检测到PWI异常。在大多数这些病例中，PWI-DWI不匹配明显大于DWI病变本身。最大的DWI病变体积和最大的不匹配体积均出现在颈动脉疾病患者中。
对于所有病因和所有解剖位置，与FLAIR相比，DWI检测急性缺血性卒中病变 的可能性几乎增加一倍。在超急性期（0至6小时），与FLAIR相比，DWI检测急性卒中的可能性增加两倍多。PWI在近50%的时间里显示出与DWI可测量的不匹配；在超过一半的这些患者中，PWI病变体积与DWI病变体积之比比核心缺血性病变本身大几倍。归根结底，所有卒中患者中约四分之一存在大量有梗死风险的潜在可挽救组织。
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