title: Improved conspicuity and delineation of high-grade primary and metastatic brain tumors using "restriction spectrum imaging": quantitative comparison with high B-value DWI and ADC.
abstract: OBJECTIVE
  Restriction spectrum imaging is a sensitive DWI technique for probing separable water diffusion compartments in tissues. Here, we evaluate RSI-CMs derived from the spherically-restricted water compartment for improved tumor conspicuity and delineation from nontumor tissue and reduced sensitivity to edema compared with high-b-value DWI and ADC.
  
  
  METHODS
  RSI was performed in 10 presurgical patients: 4 with glioblastoma, 3 with primary CNS lymphoma, and 3 with metastatic brain tumors. Multidirectional DWI data were collected at b = 500, 1500, and 4000 s/mm(2). Quantification of tumor conspicuity, edema conspicuity, and relative sensitivity to edema for RSI-CMs; DWI at b = 4000 (DWI-4000); and ADC were compared in manually drawn VOIs. Receiver operating characteristic curves were used to evaluate the sensitivity and specificity of each method for delineating tumor from normal-appearing WM.
  
  
  RESULTS
  Significant TC was seen with both RSI-CMs and DWI-4000, but not ADC. Significant EC was seen with ADC, but not RSI-CMs or DWI-4000. Significantly greater TC was seen with RSI-CMs compared with DWI-4000. Significantly reduced RSE was seen with RSI-CMs compared with both DWI-4000 and ADC. Greater sensitivity and specificity for delineating tumor from normal-appearing WM were seen with RSI-CMs (AUC = 0.91) compared with both DWI-4000 (AUC = 0.77) and ADC (AUC = 0.66).
  
  
  CONCLUSIONS
  RSI-CMs offer improved conspicuity and delineation of high-grade primary and metastatic brain tumors and reduced sensitivity to edema compared with high-b-value DWI and ADC.
authors.affiliation: University of California, San Diego, Department of Radiology, Moores Cancer Center, University of California, San Diego, La Jolla, California, USA. nswhite@ucsd.edu
authors.forename: N S
authors.initials: NS
authors.lastname: White
authors.forename: C R
authors.initials: CR
authors.lastname: McDonald
authors.forename: N
authors.initials: N
authors.lastname: Farid
authors.forename: J M
authors.initials: JM
authors.lastname: Kuperman
authors.forename: S
authors.initials: S
authors.lastname: Kesari
authors.forename: A M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001929:Brain Edema / Q000209:etiology* / Q000473:pathology*; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology* / Q000556:secondary*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity