Choline is a precursor of acetylcholine (ACH), a component of cell membranes which is commonly examined in MR spectroscopy. It resonates at 3.2 ppm chemical shift. An infant’s brain shows, due to active myelination with synthesis of membrane constituents, high choline signals .
Choline is a marker of cellular membrane turnover and therefore elevated in neoplasms, demyelination, inflammation and gliosis .
It is useful in a number of scenarios:
- diffuse glioma vs metastasis: elevation in a region of high T2 signal surrounding an enhancing mass (edema) suggests an infiltrating diffuse glioma rather than a cerebral metastasis
- GBM progression vs pseudoprogression: elevation favors tumor progression over pseudoprogression, but can be elevated if a strong immune response is present as is seen in immunotherapy