title: Standard b-value versus low b-value diffusion-weighted MRI in renal cell carcinoma: a systematic review and meta-analysis.
abstract: BACKGROUND
  We sought to determine the comparative diagnostic performance of standard b-value (800-1000 s/mm2) versus low b-value (400-500 s/mm2) diffusion-weighted magnetic resonance imaging (DW-MRI) in the detection of renal cell carcinoma (RCC).
  
  
  METHODS
  After a systematic review of the available literature, studies were included that reported b-values, used a histopathological reference standard, and allowed construction of 2 × 2 contingency tables for detection of RCC lesions using DW-MRI. In addition, a summary receiver operating characteristic (SROC) analysis was performed.
  
  
  RESULTS
  Four articles that complied with all inclusion and exclusion criteria were selected for data extraction and analysis (n = 248 lesions in 266 patients). All four studies were high quality. Standard b-value DW-MRI displayed a pooled sensitivity of 0.59 (95% confidence interval (CI): 0.51-0.67) and a pooled specificity of 0.50 (95% CI: 0.30-0.70), while low b-value DW-MRI displayed a pooled sensitivity of 0.58 (95% CI: 0.48-0.63) and a pooled specificity of 0.23 (95% CI: 0.09-0.44). The SROC curve of standard b-value DW-MRI displayed an AUC of 0.61 and a Q*index of 0.59, while the SROC curve of low b-value DW-MRI displayed an AUC of 0.68 and a Q*index of 0.64.
  
  
  CONCLUSIONS
  Standard b-value DW-MRI showed a superior specificity but an approximately equivalent sensitivity to low b-value DW-MRI in detecting RCC lesions in the kidney. However, low b-value DW-MRI displayed an overall superior diagnostic accuracy over standard b-value DW-MRI.
authors.affiliation: Department of Radiology, the Affiliated Hospital of Dali University, Yunnan 671000, China. tyl0871@163.com.
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Tang
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Du
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.forename: Chengzhi
authors.initials: C
authors.lastname: Zhang
authors.forename: Tianzhao
authors.initials: T
authors.lastname: Ouyang
authors.forename: Jinbo
authors.initials: J
authors.lastname: Hu
mesh_terms: D002292:Carcinoma, Renal Cell / Q000473:pathology*; D016206:Databases, Bibliographic; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D012372:ROC Curve; D012680:Sensitivity and Specificity