title: Combined diffusion and perfusion MR imaging as biomarkers of prognosis in immunocompetent patients with primary central nervous system lymphoma.
abstract: OBJECTIVE
  ADC derived from DWI has been shown to correlate with PFS and OS in immunocompetent patients with PCNSL. The purpose of our study was to confirm the validity of ADC measurements as a prognostic biomarker and to determine whether rCBV measurements derived from DSC perfusion MR imaging provide prognostic information.
  
  
  METHODS
  Pretherapy baseline DWI and DSC perfusion MR imaging in 25 patients with PCNSL was analyzed before methotrexate-based induction chemotherapy. Contrast-enhancing tumor was segmented and coregistered with ADC and rCBV maps, and mean and minimum values were measured. Patients were separated into high or low ADC groups on the basis of previously published threshold values of ADC(min) < 384 × 10(-6) mm(2)/s. High and low rCBV groups were defined on the basis of receiver operating curve analysis. High and low ADC and rCBV groups were analyzed independently and in combination. Multivariate Cox survival analysis was performed.
  
  
  RESULTS
  Patients with ADC(min) values < 384 × 10(-6) mm(2)/s or rCBV(mean) values < 1.43 had worse PFS and OS. The patient cohort with combined low ADC(min)-low rCBV(mean) had the worst prognosis. No other variables besides ADC and rCBV significantly affected survival.
  
  
  CONCLUSIONS
  Our study reinforces the validity of ADC values as a prognostic biomarker and provides the first evidence of low tumor rCBV as a novel risk factor for adverse prognosis in immunocompetent patients with PCNSL.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California San Francisco School of Medicine, San Francisco, California 94117, USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Valles
authors.forename: C L
authors.initials: CL
authors.lastname: Perez-Valles
authors.forename: S
authors.initials: S
authors.lastname: Regalado
authors.forename: R F
authors.initials: RF
authors.lastname: Barajas
authors.forename: J L
authors.initials: JL
authors.lastname: Rubenstein
authors.forename: S
authors.initials: S
authors.lastname: Cha
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D015415:Biomarkers; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007121:Immunocompetence; D016393:Lymphoma, B-Cell / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers