title: Between-Scanner and Between-Visit Variation in Normal White Matter Apparent Diffusion Coefficient Values in the Setting of a Multi-Center Clinical Trial.
abstract: OBJECTIVE
  To study the between-scanner variation and the between-visit reproducibility of brain apparent diffusion coefficient (ADC) measurements in the setting of a multi-center chemotherapy clinical trial for glioblastoma multiforme.
  
  
  METHODS
  ADC maps of 52 patients at six sites were calculated in-house from diffusion-weighted images obtained by seven individual scanner models of two vendors. The median and coefficient of variation (CV) of normal brain white matter ADC values from a defined region of interest were used to evaluate the differences among scanner models, vendors, magnetic fields, as well as successive visits. All patients participating in this study signed institutional review board approved informed consent. Data acquisition was performed in compliance with all applicable Health Insurance Portability and Accountability Act regulations. The study spanned from August 1, 2006, to January 29, 2008.
  
  
  RESULTS
  For baseline median ADC, no difference was observed between the different scanner models, different vendors, and different magnetic field strength. For baseline ADC CV, a significant difference was found between different scanner models (p = 0.0002). No between-scanner difference was observed in ADC changes between two visits. For between-visit reproducibility, significant difference was seen between the ADC values measured at two successive visits for the whole patient group.
  
  
  CONCLUSIONS
  The CVs varied significantly between scanners, presumably due to image noise. Consistent scanner parameter setup can improve reproducibility of the ADC measurements between visits.
authors: TeraRecon Inc., 4000 E 3rd Ave., Suite 200, 94404, Foster City, CA, USA. jinghuo@gmail.com.
authors: J
authors: J
authors: Huo
authors: Department of Radiological Science, University of California in Los Angeles, 924 Westwood Blvd, Suite 650, 90024, Los Angeles, CA, USA.
authors: J
authors: J
authors: Alger
authors: Department of Radiological Science, University of California in Los Angeles, 924 Westwood Blvd, Suite 650, 90024, Los Angeles, CA, USA.
authors: H
authors: H
authors: Kim
authors: Department of Radiological Science, University of California in Los Angeles, 924 Westwood Blvd, Suite 650, 90024, Los Angeles, CA, USA.
authors: M
authors: M
authors: Brown
authors: Department of Computer Science, San Francisco State University, San Francisco, USA.
authors: K
authors: K
authors: Okada
authors: Department of Radiological Science, University of California in Los Angeles, 924 Westwood Blvd, Suite 650, 90024, Los Angeles, CA, USA.
authors: W
authors: W
authors: Pope
authors: Department of Radiological Science, University of California in Los Angeles, 924 Westwood Blvd, Suite 650, 90024, Los Angeles, CA, USA.
authors: J
authors: J
authors: Goldin
mesh_terms: D000328:Adult; D000553:Ambulatory Care / Q000706:statistics & numerical data; D001921:Brain / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation* / Q000706:statistics & numerical data*; D056324:Diffusion Tensor Imaging / Q000295:instrumentation* / Q000706:statistics & numerical data*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States / Q000453:epidemiology; D066127:White Matter / Q000033:anatomy & histology*
keywords: ADC; Between-scanner variation; Between-visit reproducibility; Normal white matter