• John Morelli, David Porter, Fei Ai, Clint Gerdes, Megan Saettele, Thorsten Feiweier, Abraham Padua, James Dix, Michael Marra, Rajesh Rangaswamy, and Val Runge.
• Scott & White Memorial Hospital/Texas A&M Health Sciences Center, Radiology, Temple, TX, USA.
• Acta Radiol. 2013 Apr 1; 54 (3): 299-306.

BackgroundDiffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) is most commonly performed utilizing a single-shot echo-planar imaging technique (ss-EPI). Susceptibility artifact and image blur are severe when this sequence is utilized at 3 T.PurposeTo evaluate a readout-segmented approach to DWI MR in comparison with single-shot echo planar imaging for brain MRI.Material And MethodsEleven healthy volunteers and 14 patients with acute and early subacute infarctions underwent DWI MR examinations at 1.5 and 3T with ss-EPI and readout-segmented echo-planar (rs-EPI) DWI at equal nominal spatial resolutions. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) calculations were made, and two blinded readers ranked the scans in terms of high signal intensity bulk susceptibility artifact, spatial distortions, image blur, overall preference, and motion artifact.ResultsSNR and CNR were greatest with rs-EPI (8.1 ± 0.2 SNR vs. 6.0 ± 0.2; P <10(-4) at 3T). Spatial distortions were greater with single-shot (0.23 ± 0.03 at 3T; P <0.001) than with rs-EPI (0.12 ± 0.02 at 3T). Combined with blur and artifact reduction, this resulted in a qualitative preference for the readout-segmented scans overall.ConclusionSubstantial image quality improvements are possible with readout-segmented vs. single-shot EPI - the current clinical standard for DWI - regardless of field strength (1.5 or 3 T). This results in improved image quality secondary to greater real spatial resolution and reduced artifacts from susceptibility in MR imaging of the brain.

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