title: Diffusion-weighted imaging with calculated apparent diffusion coefficient of enhancing extra-axial masses.
abstract: OBJECTIVE
  Sometimes intracranial contrast-enhancing tumors like meningiomas, metastases, lymphomas, and schwannomas can mimic each other. It was the aim of the present study to investigate if intracranial contrast-enhancing lesions can be reliably differentiated with the help of diffusion-weighted imaging with calculated apparent diffusion coefficients (ADCs).
  
  
  METHODS
  29 patients (ages ranging from 22 to 82 years, mean age of 58.6 years) were included. Nine meningiomas, 7 metastases, 6 lymphomas, and 7 schwannomas were investigated. The ADC value in the lesions and in the perifocal edema was analyzed.
  
  
  RESULTS
  For the lymphomas, the authors measured the lowest ADC values in the contrast-enhancing part (0.59 +/- 0.09 . 10(-3) mm2/sec). The meningiomas showed a mean ADC value of 0.98 +/- 0.18 . 10(-3) mm2/sec. The schwannomas and metastases showed higher ADC values of 1.33 +/- 0.28 . 10(-3) mm2/sec and 1.05 +/- 0.20 . 10(-3) mm2/sec. The authors saw a statistically significant difference between lymphomas, meningiomas, and metastases concerning the ADC values in the contrast-enhancing part.
  
  
  CONCLUSIONS
  In spite of a small sample size and partly a wide range of values, the authors found statistically significant differences between meningiomas, metastases, and lymphomas concerning ADC values. Nevertheless, a differentiation of these lesions only with the help of ADC values seems questionable.
authors.affiliation: Departments of Diagnostic Radiology, University Hospital of Regensburg, Regensburg, Germany. ulrich.dorenbeck@ukb.uni-bonn.de
authors.forename: U
authors.initials: U
authors.lastname: Dorenbeck
authors.forename: I Q
authors.initials: IQ
authors.lastname: Grunwald
authors.forename: J
authors.initials: J
authors.lastname: Schlaier
authors.forename: S
authors.initials: S
authors.lastname: Feuerbach
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis; D008579:Meningioma / Q000175:diagnosis; D008875:Middle Aged