title: The clinical utility of reduced-distortion readout-segmented echo-planar imaging in the head and neck region: initial experience.
abstract: OBJECTIVE
  To evaluate whether readout-segmented echo-planar imaging (RS-EPI) diffusion weighted image (DWI) can diminish image distortion in the head and neck area, compared with single-shot (SS)-EPI DWI.
  
  
  METHODS
  We conducted phantom and patient studies using 3 T magnetic resonance imaging (MRI) with a 16-channel coil. For the phantom study, we evaluated distortion and signal homogeneity in gel phantoms. For the patient study, 29 consecutive patients with clinically suspicious parotid lesions were prospectively enrolled. RS-EPI and SS-EPI DWI were evaluated by two independent readers for identification of organ/lesion and distortion, using semiquantitative scales and quantitative scores. Apparent diffusion coefficient (ADC) values and contrast-noise ratios of parotid tumours (if present; n = 15) were also compared.
  
  
  RESULTS
  The phantom experiments showed that RS-EPI provided less distorted and more homogeneous ADC maps than SS-EPI. In the patient study, RS-EPI was found to provide significantly less distortion in almost all organs/lesions (p < 0.05), according to both semiquantitative scales and quantitative scores. There was no significant difference in ADC values and contrast-noise ratios between the two DWI techniques.
  
  
  CONCLUSIONS
  The distortion in DWI was significantly reduced with RS-EPI in both phantom and patient studies. The RS-EPI technique provided more homogenous images than SS-EPI, and can potentially offer higher image quality in the head and neck area.
  
  
  CONCLUSIONS
  The distortion in DWI is significantly reduced with RS-EPI compared with SS-EPI. Structures in the head and neck were identified more clearly using RS-EPI. No significant difference in ADC values was found between the techniques.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-Ku, Kyoto, 606-8507, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Koyasu
authors.forename: Mami
authors.initials: M
authors.lastname: Iima
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Umeoka
authors.forename: Nobuko
authors.initials: N
authors.lastname: Morisawa
authors.forename: David A
authors.initials: DA
authors.lastname: Porter
authors.forename: Juichi
authors.initials: J
authors.lastname: Ito
authors.forename: Denis
authors.initials: D
authors.lastname: Le Bihan
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010307:Parotid Neoplasms / Q000175:diagnosis; D019047:Phantoms, Imaging; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media