title: [Evaluation of signal noise ratio on analysis of clear cell renal cell carcinoma using DWI with multi-b values].
abstract: OBJECTIVE
  To explore the influence of signal noise ratio (SNR) on analysis of clear cell renal cell carcinoma (CCRCC) using DWI with multi-b values.
  
  
  METHODS
  The images of 17 cases with CCRCC were analyzed, including 17 masses and 9 pure cysts. The signal intensity of the cysts and masses was measured separately on DWI for each b value. The minimal SNR, as the threshold, was recorded when the signal curve manifest as the single exponential line. The SNR of the CCRCC was calculated on DWI for each b value, and compared with the threshold by independent Two-sample t Test.
  
  
  RESULTS
  The signal decreased on DWI with increased b factors for both pure cysts and CCRCC. The threshold is 1.29 ± 0.17, and the signal intensity of the cysts on DWI with multi-b values shown as a single exponential line when b ≤ 800 s/mm(2). For the CCRCC, the SNR is similar to the threshold when b = 1 000 s/mm(2) (t = 0.40, P = 0.69), and is lower when b = 1 200 s/mm(2) (t = -2.38, P = 0.03).
  
  
  CONCLUSIONS
  The SNR should be sufficient for quantitative analysis of DWI, and the maximal b value is 1000 s/mm(2) for CCRCC.
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China.
authors.forename: Jiule
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China. Email: suzhxingwei@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Xing
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Dai
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Radiology, the First People's Hospital of Changzhou, Changzhou 213003, China.
authors.forename: Dengfa
authors.initials: D
authors.lastname: Li
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000473:pathology*; D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies