title: Histogram analysis of apparent diffusion coefficient maps for differentiating primary CNS lymphomas from tumefactive demyelinating lesions.
abstract: OBJECTIVE
  This study intended to investigate the usefulness of histogram analysis of apparent diffusion coefficient (ADC) maps for discriminating primary CNS lymphomas (PCNSLs), especially atypical PCNSLs, from tumefactive demyelinating lesions (TDLs).
  
  
  METHODS
  Forty-seven patients with PCNSLs and 18 with TDLs were enrolled in our study. Hyperintense lesions seen on T2-weighted images were defined as ROIs after ADC maps were registered to the corresponding T2-weighted image. ADC histograms were calculated from the ROIs containing the entire lesion on every section and on a voxel-by-voxel basis. The ADC histogram parameters were compared among all PCNSLs and TDLs as well as between the subgroup of atypical PCNSLs and TDLs. ROC curves were constructed to evaluate the diagnostic performance of the histogram parameters and to determine the optimum thresholds.
  
  
  RESULTS
  The differences between the PCNSLs and TDLs were found in the minimum ADC values (ADCmin) and in the 5th and 10th percentiles (ADC5% and ADC10%) of the cumulative ADC histograms. However, no statistical significance was found in the mean ADC value or in the ADC value concerning the mode, kurtosis, and skewness. The ADCmin, ADC5%, and ADC10% were also lower in atypical PCNSLs than in TDLs. ADCmin was the best indicator for discriminating atypical PCNSLs from TDLs, with a threshold of 556×10(-6) mm2/s (sensitivity, 81.3 %; specificity, 88.9%).
  
  
  CONCLUSIONS
  Histogram analysis of ADC maps may help to discriminate PCNSLs from TDLs and may be particularly useful in differentiating atypical PCNSLs from TDLs.
authors: 1 Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea.
authors: Shan Shan
authors: SS
authors: Lu
authors: Sang Joon
authors: SJ
authors: Kim
authors: Namkug
authors: N
authors: Kim
authors: Ho Sung
authors: HS
authors: Kim
authors: Choong Gon
authors: CG
authors: Choi
authors: Young Min
authors: YM
authors: Lim
mesh_terms: D000328:Adult; D002493:Central Nervous System Diseases / Q000175:diagnosis*; D016543:Central Nervous System Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D003711:Demyelinating Diseases / Q000175:diagnosis*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008223:Lymphoma / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media
keywords: apparent diffusion coefficient (ADC); demyelinating disease; diffusion MRI; histogram analysis; primary CNS lymphoma (PCNSL)