title: Clinical evaluation of single-shot and readout-segmented diffusion-weighted imaging in stroke patients at 3 T.
abstract: BACKGROUND
  Diffusion-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.
  
  
  OBJECTIVE
  To evaluate a readout-segmented approach to DWI MR in comparison with single-shot echo planar imaging for brain MRI.
  
  
  METHODS
  Eleven 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.
  
  
  RESULTS
  SNR 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.
  
  
  CONCLUSIONS
  Substantial 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.
authors: Scott & White Memorial Hospital/Texas A&M Health Sciences Center, Radiology, Temple, TX, USA.
authors: John
authors: J
authors: Morelli
authors: David
authors: D
authors: Porter
authors: Fei
authors: F
authors: Ai
authors: Clint
authors: C
authors: Gerdes
authors: Megan
authors: M
authors: Saettele
authors: Thorsten
authors: T
authors: Feiweier
authors: Abraham
authors: A
authors: Padua
authors: James
authors: J
authors: Dix
authors: Michael
authors: M
authors: Marra
authors: Rajesh
authors: R
authors: Rangaswamy
authors: Val
authors: V
authors: Runge
mesh_terms: D000328:Adult; D016477:Artifacts; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D012680:Sensitivity and Specificity; D020521:Stroke / Q000473:pathology*