Calculation of Apparent Diffusion Coefficients (ADCs) in Brain Using Two-Point and Six-Point MethodsBurdette, Jonathan H.; Elster, Allen D.; Ricci, Peter E.Journal of Computer Assisted Tomography: September-October 1998 - Volume 22 - Issue 5 - p 792-794 Neuroradiology: Technical Note Abstract Author Information We evaluated the relative accuracy of calculating apparent diffusion coefficients (ADCs) of intracranial tissues using a two-point versus a six-point regression technique. Echo planar diffusion-weighted MRI was performed at 1.5 T in three standard locations and in pathologic regions in 10 subjects using gradient strengths corresponding to b values of 1, 100, 200, 500, 800, and 1,000 s/mm2. Estimation of ADCs was made using two methods: a nonlinear regression model using measurements from the full set of b values (six-point technique) and linear estimation using b values of 1 and 1,000 only (two-point technique). A high correlation between the two methods was noted (R 2 = 0.999), and the mean percentage difference was 0.84%. These results suggest there is little error in estimating brain ADCs using a two-point technique. From the Department of Radiology, Division of Radiologic Sciences, Wake Forest University School of Medicine, Bowman Gray Campus, Medical Center Boulevard, Winston-Salem, NC 27157-1088, U.S.A. Address correspondence and reprint requests to Dr. J. H. Burdette. © 1998 Lippincott Williams & Wilkins, Inc.