Weiying Dai1, Philip M. Robson1, Ajit Shankaranarayanan2, David C. Alsop1
1Radiology, Beth Israel Deaconess Medical Center,Harvard Medical School, Boston, MA, United States; 2Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States
Conventional ASL perfusion quantification requires division by a proton density reference image and assumes a uniform brain-blood partition coefficient. The brain-blood partition coefficient is not constant, however, and may especially differ in areas of pathology. In cortical regions where CSF, white matter and gray matter may all be mixed within a voxel, division by the proton density image can also add nonlinear systematic errors. Here we propose using an optimized inversion preparation to generate an image whose intensity is essentially independent of tissue type. This highly homogeneous image can replace the proton density image and makes the assumption of a brain-blood partition coefficient unnecessary. In-vivo results demonstrate that such homogeneous contrast is achievable and can be used to improve the pixel-by-pixel perfusion measurement.