title: Correlation between tissue metabolism and cellularity assessed by standardized uptake value and apparent diffusion coefficient in peritoneal metastasis.
abstract: OBJECTIVE
  To evaluate the correlation between standardized uptake value (SUV) (tissue metabolism) and apparent diffusion coefficient (ADC) (water diffusivity) in peritoneal metastases.
  
  
  METHODS
  Patients with peritoneal dissemination detected on (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) were prospectively recruited for MRI examinations with informed consent and the study was approved by the local Institutional Review Board. FDG-PET/CT, diffusion-weighted imaging (DWI), MRI, and DWI/MRI images were independently reviewed by two radiologists based on visual analysis. SUVmax/SUVmean and ADCmin/ADCmean were obtained manually by drawing ROIs over the peritoneal metastases on FDG-PET/CT and DWI, respectively. Diagnostic characteristics of each technique were evaluated. Pearson's coefficient and McNemar and Kappa tests were used for statistical analysis.
  
  
  RESULTS
  Eight patients were recruited for this prospective study and 34 peritoneal metastases were evaluated. ADCmean was significantly and negatively correlated with SUVmax (r = -0.528, P = 0.001) and SUVmean (r = -0.548, P = 0.001). ADCmin had similar correlation with SUVmax (r = -0.508, P = 0.002) and SUVmean (r = -0.513, P = 0.002). DWI/MRI had high diagnostic performance (accuracy = 98%) comparable to FDG-PET/CT, in peritoneal metastasis detection. Kappa values were excellent for all techniques.
  
  
  CONCLUSIONS
  There was a significant inverse correlation between SUV and ADC.
authors.affiliation: Department of Diagnostic Radiology, University of Hong Kong, Hong Kong, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Yu
authors.forename: Elaine Yuen Phin
authors.initials: EY
authors.lastname: Lee
authors.forename: Vincent
authors.initials: V
authors.lastname: Lai
authors.forename: Queenie
authors.initials: Q
authors.lastname: Chan
mesh_terms: D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000556:secondary*; D010537:Peritoneum / Q000378:metabolism* / Q000473:pathology*; D011620:Psyllium / Q000493:pharmacokinetics*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
chemical_list: D011620:Psyllium
keywords: ADC; FDG-PET/CT; SUV; diffusion-weighted imaging; peritoneal metastases