title: Single breath-hold diffusion-weighted MRI of the liver with parallel imaging: initial experience.
abstract: OBJECTIVE
  To evaluate prospectively the improvement in the signal:noise ratio (SNR), with the use of parallel technique in single breath-hold diffusion-weighted imaging (DWI) of the liver and its affect on apparent diffusion coefficient (ADC) measurements.
  
  
  METHODS
  This study was approved by our institutional review board. Written informed consent was obtained from all participants. Fifteen patients underwent single breath-hold DWI of the liver with and without parallel imaging technique. SNR and ADC values were measured over a lesion-free right hepatic lobe by two radiologists in both series. When a focal hepatic lesion was present the contrast:noise ratio (CNR) and ADC were also measured. Paired Student's t-tests were used for statistical analysis.
  
  
  RESULTS
  Mean SNR values of the liver were 20.82+/-7.54 and 15.83+/-5.95 for DWI with and without parallel imaging, respectively. SNR values measured in DWI using parallel imaging were found to be significantly higher (p<0.01). Mean ADC of the liver were 1.61+/-0.45 x 10(-3)mm(2)/s and 1.56+/-0.28 x 10(-3)mm(2)/s for DWI with and without parallel imaging, respectively. No significant difference was found between the two sequences for hepatic ADC measurement (p>0.05). Overall lesion CNR was found to be higher in DWI with parallel imaging.
  
  
  CONCLUSIONS
  Parallel imaging is useful in improving SNR of single breath-hold DWI of the liver without compromising ADC measurements.
authors.affiliation: Gazi University School of Medicine, Department of Radiology, Besevler-Ankara, Turkey. yusuf@tr.net <yusuf@tr.net>
authors.forename: A Y
authors.initials: AY
authors.lastname: Oner
authors.forename: H
authors.initials: H
authors.lastname: Celik
authors.forename: S O
authors.initials: SO
authors.lastname: Oktar
authors.forename: T
authors.initials: T
authors.lastname: Tali
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000175:diagnosis / Q000556:secondary; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis; D003110:Colonic Neoplasms / Q000473:pathology; D005260:Female; D006391:Hemangioma / Q000175:diagnosis; D006801:Humans; D008099:Liver / Q000473:pathology*; D008107:Liver Diseases / Q000175:diagnosis*; D008113:Liver Neoplasms / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity