PT - JOURNAL ARTICLE AU - Mark C. DeLano AU - Thomas G. Cooper AU - James E. Siebert AU - Michael J. Potchen AU - Karthik Kuppusamy TI - High-b-value Diffusion-weighted MR Imaging of Adult Brain: Image Contrast and Apparent Diffusion Coefficient Map Features DP - 2000 Nov 01 TA - American Journal of Neuroradiology PG - 1830--1836 VI - 21 IP - 10 4099 - http://www.ajnr.org/content/21/10/1830.short 4100 - http://www.ajnr.org/content/21/10/1830.full SO - Am. J. Neuroradiol.2000 Nov 01; 21 AB - BACKGROUND AND PURPOSE: Recent improvements in MR gradient technology allow significant increases in diffusion weighting without prohibitive signal-to-noise degradation. The purpose of our investigation was to establish normative references for the signal intensity characteristics and apparent diffusion coefficient values of the adult brain at high b values.METHODS: Fifty adults underwent diffusion-weighted single-shot spin-echo echo-planar MR imaging. Isotropic diffusion-weighted images were obtained with b values of 0, 1000, 2000, 2500, 3000, and 3500 s/mm2. Qualitative assessments were made in multiple regions of interest in gray and white matter. Three apparent diffusion coefficient maps were generated for each of six patients with a 2-point technique at a b value of 0 and at b values of 1000, 2000, and 3000 s/mm2.RESULTS: Increasing b values result in a progressive decrease in the gray to white matter signal intensity ratio. Isointensity between gray and white matter results at b values between 1000 and 2000 s/mm2. At b values greater than 2000, the gray-white pattern reverses relative to the usual b value of 1000. Apparent diffusion coefficient values were shown to decrease with increasing b values.CONCLUSION: Attention to the reversal of gray-white contrast and the dependence of apparent diffusion coefficient on the b value are important in avoiding erroneous assignment of pathologic abnormalities to normal regions. This study provides the normative data for future diffusion investigations performed at high b values.