Fig 2. Histopathologic correlation of MR imaging data with stereotactic biopsy specimens in a 50-year-old patient with a right parietal grade IV astrocytoma. A–D, Top row shows axial 3D T1-weighted images (TR/TE, 20/4.6 ms) with contrast (A), coregistered ADC map (B), coregistered rCBV map (C), and corresponding histopathologic results for an "infiltrated tissue" sample (D). E–H, Bottom row shows axial 3D T1-weighted images (TR/TE, 20/4.6 ms) with contrast (E), coregistered ADC map (F), coregistered rCBV map (G), and corresponding histopathologic results for a "bulk tumor" sample (H). Regions of interest where ADC and rCBV have been measured are illustrated (arrows). The samples were immunohistochemically stained by using a monoclonal antibody against the CD34 antigen to assess microvessel density (arrows) and counterstained with hematoxylin to assess cell density (arrowheads) (original magnification, x 400).