title: The added value of the apparent diffusion coefficient calculation to magnetic resonance imaging in the differentiation and grading of malignant brain tumors.
abstract: OBJECTIVE
  ADC calculation can improve the diagnostic efficacy of MR imaging in brain tumor grading and differentiation.
  
  
  METHODS
  Apparent diffusion coefficient (ADC) values and ratios of 33 low-grade (23 astrocytomas, 10 oligodendrogliomas) and 40 high-grade (25 metastases and 15 high-grade astrocytomas) malignant tumors were prospectively evaluated.
  
  
  RESULTS
  Tumoral ADC values (r=-0.738, P <0.000) and ratios (r=-0.746, P < 0.000) were well correlated with higher degree of malignancy and quite effective in grading of malignant brain tumors (P < 0.000). By using cutoff values of 0.99 for tumoral ADC value and 1.22 for normalized ADC ratio, the sensitivity of MR imaging could be increased from 72.22% to 93.75% and 90.63%, the specificity from 81.08% to 92.68% and 90.24%, PPV from 78.79% to 90.91% and 87.88%, and NPV from 75.00% to 95.00% and 92.50%, respectively.
  
  
  CONCLUSIONS
  ADC calculation was quite effective in grading of malignant brain tumors but not in differentiation of them and added more information to conventional contrast-enhanced MR imaging.
authors.affiliation: Department of Radiology, Gulhane Military Medical Academy, Etlik, 06018 Ankara, Turkey. nbulak@gata.edu.tr
authors.forename: Nail
authors.initials: N
authors.lastname: Bulakbasi
authors.forename: Inanc
authors.initials: I
authors.lastname: Guvenc
authors.forename: Onder
authors.initials: O
authors.lastname: Onguru
authors.forename: Ersin
authors.initials: E
authors.lastname: Erdogan
authors.forename: Cem
authors.initials: C
authors.lastname: Tayfun
authors.forename: Taner
authors.initials: T
authors.lastname: Ucoz
mesh_terms: D000293:Adolescent; D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000175:diagnosis / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016037:Single-Blind Method
chemical_list: D003287:Contrast Media