Cholesterol of myelin is the determinant of gray‐white contrast in MRI of brain

The relative brightness of adult white matter in T1‐weighted MRI arises from myelin, but the mechanisms responsible remain to be clarified. Koenig et al. [Magn. Reson. Med. 14, 482 (1990)] conjectured that the cholesterol of myelin (∼ 30% of its lipid) was responsible. We present 1/T1 and magnetization transfer contrast imaging data [Wolff and Balaban, Magn. Reson. Med. 10, 135 (1989)] on a model system— 50% lipid—50% water by weight, with the lipid one‐half phosphatidyl cholinc (PC) and one‐half cholesterol—and a control in which the lipid is all PC. The differences between the model and control samples mimic the myelin contribution to white matter in both experiments. © 1991 Academic Press, Inc.

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