A comparison of fast spin-echo, fluid-attenuated inversion-recovery, and diffusion-weighted MR imaging in the first 10 days after cerebral infarction

BACKGROUND AND PURPOSE: Echo-planar diffusion-weighted and fluid-attenuated inversion-recovery (FLAIR) imaging have both proved valuable for detecting acute ischemic infarcts, but little is known about the value of diffusion- weighted imaging beyond the acute infarct period. Furthermore, no direct co mparison of the techniques has been published. We compared the diagnostic u tility of diffusion-weighted, FLAIR, and T2-weighted fast spin-echo (FSE) i maging for detecting cerebral infarctions up to 10 days old. METHODS: FSE, FLAIR, and diffusion-weighted MR sequences were obtained pros pectively over a 6-month period in 212 patients with suspected cerebral inf arctions, Seventy patients with nonhemorrhagic ischemic infarcts less than 10 days old whose symptoms lasted longer than 48 hours were identified. The three sequences were compared for detectability and conspicuity of abnorma lities that correlated with the neurologic deficit. RESULTS: Seventy-two symptomatic infarcts were found in the 70 patients, Di ffusion-weighted imaging detected 70 (97%), FLAIR, 69 (96%), and FSE, 64 (8 9%) of the 72 lesions. Only the difference between diffusion-weighted and F SE imaging approached statistical significance. There was no difference in the number of lesions detected in the patients imaged 48 hours or more afte r infarction, Lesion conspicuity on diffusion-weighted images was judged su perior to that on FSE and FLAIR images in 55 (77%) and 47 (67%) of the case s, respectively. FLAIR images were judged superior to FSE in 34 (48%) of th e cases, CONCLUSION: Diffusion-weighted images showed more infarcts than FLAIR and F SE images, and FLAIR images showed more than FSE images, but the difference s were not statistically significant. Lesion conspicuity, however, was cons istently better on diffusion-weighted images than on either FLAIR or FSE im ages throughout the Ill-day period, Acquisition of diffusion-weighted image s in the late acute and subacute periods after ischemic cerebral infarction appears to be beneficial.