Curr Probl Diagn Radiol. 2003 Sep-Oct;32(5):194-217
Cakirer S, Karaarslan E, Arslan A.
In this work, the brain lesions that cause spontaneously hyperintense T1 signal on MRI were studied under seven categories.
The first category includes lesions with hemorrhagic components, such as infarct, encephalitis, intraparenchymal hematoma, cortical contusion, diffuse axonal injury, subarachnoid hemorrhage, subdural and epidural hematoma, intraventricular hemorrhage, vascular malformation and aneurysm, and hemorrhagic neoplasm.
The second category includes protein-containing lesions, such as colloid cyst, craniopharyngioma, Rathke's cleft cyst, and atypical epidermoid.
The third category includes lesions with fatty components, such as lipoma, dermoid, and lipomatous meningioma.
Lesions with calcification or ossification, such as endocrine-metabolic disorder, calcified neoplasm, infection, and dural osteoma, constitute the fourth category, whereas the fifth category includes lesions with other mineral accumulation, such as acquired hepatocerebral degeneration and Wilson disease.
The sixth category includes melanin-containing lesions, such as metastasis from melanoma and leptomeningeal melanosis.
The last category is the miscellaneous group, which includes ectopic neurohypophysis, chronic stages of multiple sclerosis, and neurofibromatosis type I.
The above-mentioned lesions are presented with their typical T1-hyperintense images, and the underlying reasons for those appearances in magnetic resonance imaging are discussed.