Readout-segmented echo-planar imaging in diffusion-weighted MR imaging of acute infarction of the brainstem and posterior fossa: comparison of single-shot echo-planar diffusion-weighted sequences.

OBJECTIVE: The purpose of this study was to evaluate the clinical usefulness of readout-segmented echo-planar imaging (rs-EPI) in the diagnosis of acute infarction of the brainstem and posterior fossa, by comparing its results with those of single-shot echo-planar imaging (ss-EPI) at 3-T magnetic resonance imaging.

MATERIALS AND METHODS: Twenty-nine patients with acute infarctions of the brainstem and posterior fossa underwent both ss-EPI and rs-EPI. Two readers independently assessed two sets of diffusion-weighted (DW) images for the qualitative comparison of image quality. Signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated for the assessment of image parameters.

RESULTS: There were no significant differences in the conspicuity of acute infarction upon qualitative comparison; however, distinctions of anatomical structures, susceptibility artifact, the presence of uncertain high signal intensity in the brain parenchyma, and overall image quality were significantly better in rs-EPI DW images. There were no significant differences in SNR, lesion contrast, CNR, and apparent diffusion coefficient values of acute infarction and normal thalamus between rs-EPI and ss-EPI.

CONCLUSION: rs-EPI DWI is a clinically useful technique for evaluating lesions in the brainstem and posterior fossa by producing high-resolution DW images with reduced susceptibility artifact. However, there are no significant differences in the conspicuity of acute infarctions in the brainstem and posterior fossa between rs-EPI and ss-EPI.