title: Value of pretherapeutic DWI in evaluating prognosis and therapeutic effect in immunocompetent patients with primary central nervous system lymphoma given high-dose methotrexate-based chemotherapy: ADC-based assessment.
abstract: OBJECTIVE
  To investigate apparent diffusion coefficient (ADC) as a prognostic indicator in primary central nervous system lymphoma (PCNSL) by analysing patient clinical characteristics and pretherapeutic diffusion-weighted imaging (DWI).
  
  
  METHODS
  Clinical characteristics and pretherapeutic DWI were studied retrospectively in 28 patients receiving high-dose methotrexate (HD-MTX)-based chemotherapy. Mean (ADCmean), 95th percentile (ADC95%), and 5th percentile (ADC5%) ADC values of the enhancing tumour volume were measured. The influence of prognostic parameters on progression-free survival (PFS) was investigated by log-rank test and Cox regression analysis. Correlations between the variables and PFS or the level of Ki-67 expression were analysed. ADC and clinical features were analysed using an independent sample t-test between the complete response (CRi) and partial response (PRi) groups after initial four cycles of chemotherapy. Receiver operating characteristic (ROC) curves were constructed using ADC parameters.
  
  
  RESULTS
  Patients with CRi, lower Ki-67 level, higher Karnofsky performance status (KPS), ADC5%, or ADCmean showed better PFS. The level of Ki-67 expression and ADC5% were independent risk factors. There was a positive correlation between KPS, ADC5%, and PFS, and negative correlation between ADC5%, PFS, and the level of Ki-67 expression. There was a significant difference for PFS, KPS, ADCmean, and ADC5% between CRi and non-CRi; however, ADC5% outperformed ADCmean because the area under the ROC curve (AUC) using ADC5% (0.983) was higher than the AUC using ADCmean (0.822).
  
  
  CONCLUSIONS
  ADC measurements, especially ADC5%, are useful predictors for PFS and response to HD-MTX in PCNSL.
authors.affiliation: Department of Radiology, The 105th Hospital of Chinese PLA, Hefei 230031, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiology, The 105th Hospital of Chinese PLA, Hefei 230031, People's Republic of China.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Pathology, The 105th Hospital of Chinese PLA, Hefei 230031, People's Republic of China.
authors.forename: X-X
authors.initials: XX
authors.lastname: Wang
authors.affiliation: Basic Medicine College, Anhui Medical University, Hefei 230032, People's Republic of China.
authors.forename: X-F
authors.initials: XF
authors.lastname: Deng
authors.affiliation: Department of Radiology, The 105th Hospital of Chinese PLA, Hefei 230031, People's Republic of China. Electronic address: zyz105f@163.com.
authors.forename: Y-Z
authors.initials: YZ
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic; D001921:Brain / Q000000981:diagnostic imaging*; D016543:Central Nervous System Neoplasms / Q000188:drug therapy* / Q000276:immunology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy* / Q000276:immunology; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use*; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D000964:Antimetabolites, Antineoplastic; D008727:Methotrexate