Acute and chronic stroke: Navigated spin-echo diffusion-weighted MR imaging

PURPOSE: The authors evaluated a phase-navigated spin-echo (SE) motion-correction sequence for use at diffusion-weighted (DW) magnetic resonance (MR) imaging after cerebral infarction. MATERIALS AND METHODS: Twenty-nine patients underwent 32 conventional T2-weighted fast SE and SE DW imaging after stroke (n = 25), transient ischemic attack (n = 3), or reversible ischemic neurologic deficit (n = 1). Imaging was performed in a standard head holder with standard padding. Apparent diffusion coefficient (ADC) maps were reconstructed. RESULTS: DW images depicted high signal intensity compatible with localization of the ischemic symptoms in all cases. Lesions were depicted more clearly on DW than on T2-weighted images. On DW images, acute infarct ADC values were uniformly low (mean, 0.401 x 10(-5) cm(2)/sec +/- 0.143 [standard deviation]) compared with control ADC values (mean, 0.754 x 10(-5) cm(2)/sec +/- 0.201). ADC values of chronic infarcts were supranormal (mean, 1.591 x 10(-5) cm(2)/sec +/- 0.840) compared with control values (mean, 0.788 x 10(-5) cm(2)/sec +/- 0.166). DW imaging did not show a change after transient ischemic attack. With reversible ischemic neurologic deficit, however, hyperintensity on DW images and low ADC resolved after symptoms abated. CONCLUSION: Clinical phase-navigated SE DW imaging improved early diagnosis of stroke and helped differentiate acute from chronic stroke. Changes on DW images are reversed after symptoms resolve.