What Are Hyperintense Lesions?

Hyperintense lesions are bright, white spots shown on certain types of magnetic resonance imaging (MRI) scans. They can be found on the brain, spinal cord, and liver among other areas of the body and can be related to multiple sclerosis, dementia, diabeted and simple aging. Hyperintense lesions can also referred to as hyperintense foci, hyperintensities, or bright signals. The type of MRI process that reveals these lesions is referred to as T2-weighted MRI and is a fairly new technique. Scientists and doctors are still evaluating the exact diagnostic meaning of hyperintense lesions in different cases; in some cases it has been been found that there is no outward symptom related to the lesions.

MRIs use interwoven magnetic fields to create images of the all of the tissues inside a body and is most often utilized to make the soft tissues appear in higher contrast than you would see in an x-ray or computed tomography scan. T2-weighted MR imaging uses specific settings for two factors of the imaging process: echo time and repetition time. The bright spots known as hyperintense lesions show areas where the tissue contains more fluid than normal for the tissue type and pools of free water. It is also possible for the data from a T2 MRI to be adjusted so that the free water is not highlighted and the focus is on high concentrations of water within the tissue. This is known as a FLAIR sequence, and is especially useful in testing for multiple sclerosis.

Tissue that has a higher concentration of water indicates that some form of damage has occurred in the area causing the edema that is part of the body’s repair process. Diabetes and hypertension have both been linked to larger-than-average size of hyperintense lesions in the central nervous system; of the two, however, only diabetes has been shown to increase the rate of growth of lesions. In some cases, like Creutzfeldt-Jakob disease which causes progressive dementia, the presence of hyperintense lesions can help lead to the proper diagnosis of the prion disease rather than categorize the illness as typical degenerative dementia. Hyperintense lesions on the liver show the presence of cysts — whether caused by trauma, polycystic disease, or parasites — and/or some forms of cancer. In contrast, one study measured growth of hyperintense lesions on the optical nerve and found no correlation between the presence of lesions and disorders of the eye.