Wernicke-Korsakoff syndrome (WKS) is a serious neurological disorder caused primarily by a deficiency of vitamin B1 (thiamine), often linked to chronic alcoholism or malnutrition. It consists of two related conditions: Wernicke encephalopathy, an acute phase characterized by confusion, ataxia (loss of coordination), and eye movement abnormalities; and Korsakoff syndrome, a chronic phase marked by severe memory impairment and confabulation. Magnetic Resonance Imaging (MRI) plays a crucial role in detecting and assessing this syndrome by revealing characteristic brain changes caused by thiamine deficiency.
MRI detects Wernicke-Korsakoff syndrome by identifying specific abnormalities in brain regions that are particularly vulnerable to thiamine deficiency. These areas include the **mammillary bodies**, **thalamus**, **periaqueductal gray matter**, **tectal plate**, and **medial thalami**. The damage in these regions results from metabolic disturbances leading to neuronal loss, gliosis (scarring), and sometimes hemorrhage. MRI sequences sensitive to these changes, especially T2-weighted and FLAIR (Fluid Attenuated Inversion Recovery) images, show **hyperintensities**—areas that appear brighter than normal brain tissue—indicating edema or gliosis in these critical structures.
In the acute phase of Wernicke encephalopathy, MRI typically reveals symmetrical hyperintense signals on T2 and FLAIR images in the medial thalami, mammillary bodies, tectal plate, and periaqueductal area. These findings reflect swelling and inflammation due to thiamine deficiency. Sometimes, contrast-enhanced T1-weighted images may show enhancement of the mammillary bodies, indicating breakdown of the blood-brain barrier. These imaging features help differentiate Wernicke encephalopathy from other neurological disorders.
As the syndrome progresses to Korsakoff syndrome, MRI may show atrophy or shrinkage of the mammillary bodies and other affected regions, reflecting permanent neuronal loss. This atrophy correlates with the severe memory deficits and cognitive impairments seen clinically. The chronic phase changes are less likely to show active inflammation but rather structural damage and volume loss.
Diffusion-weighted imaging (DWI), a sensitive MRI technique that detects changes in water molecule movement, can sometimes identify early cytotoxic edema in affected areas, even before changes become apparent on conventional T2 or FLAIR images. This can be useful for early diagnosis and treatment initiation.
MRI also helps exclude other causes of similar symptoms, such as stroke, tumors, infections, or demyelinating diseases, by providing detailed images of brain anatomy and pathology. The pattern of symmetrical involvement of specific brain regions is a hallmark of Wernicke-Korsakoff syndrome and aids in diagnosis.
In summary, MRI detects Wernicke-Korsakoff syndrome by revealing characteristic symmetrical hyperintensities in the medial thalami, mammillary bodies, periaqueductal gray, and related structures during the acute phase, and by showing atrophy of these regions in the chronic phase. These imaging findings, combined with clinical evaluation and laboratory tests, enable accurate diagnosis and timely treatment to prevent irreversible brain damage.
