Case 27 - Thiamine Deficiency: MRI

Dr. Yousem has provided the following report as a sample report for your reference. It does not match the case reviewed in the video.

MRI brain with and without contrast

CLINICAL HISTORY: Altered mental status.  History of AML and breast cancer.

COMPARISON: None

TECHNIQUE:

Sagittal T1, axial T2, axial FLAIR, and axial diffusion weighted images were obtained without administration of contrast agent.  Axial and coronal T1 weighted images were obtained after uneventful administration of 0.1 mmol/kg of Magnevist.  ADC maps were constructed from the axial diffusion weighted scans after 3D post-processing from raw data.

FINDINGS:

There is ill-defined mild hyperintensity on DWI pulse sequence involving the bilateral medial thalami and periventricular white matter surrounding the third ventricle.  Although diffusion evaluation is somewhat limited in the region of the skull base, there is probable restricted diffusion within the bilateral mammillary bodies with associated enhancement of the structures upon contrast administration.  There is significant corresponding increased T2/FLAIR signal in these regions as well as slightly increased signal involving the periaqueductal gray.    Given this constellation of findings, the possibility of Wernicke's encephalopathy should be considered, and correlation for thiamine deficiency is recommended.

Although infarction in the distribution of artery of Percheron may also affect the medial thalami, this pattern of involvement which includes the mammillary bodies and periaqueductal gray makes arterial infarction a much less likely differential consideration.

There are scattered foci of T2/FLAIR hyperintensity in the periventricular and deep subcortical white matter which are nonspecific, but are statistically most likely secondary to chronic small vessel ischemic disease.  Incidental note is made of a partially empty sella.

There is no intracranial mass, mass effect or midline shift.  Other than enhancement within the mammillary bodies as described above, there is no evidence of abnormal enhancement.  Cortical gray white differentiation is within normal limits.  Ventricles and cisternal spaces are unremarkable for age.  There is no evidence of restricted diffusion to indicate ischemia or infarct.  Major flow voids are preserved.  Orbits and paranasal sinuses are unremarkable.  Left mastoid effusion is present.

There is diffusely decreased heterogeneous T1 marrow signal, likely secondary to marrow rebound or infiltration from either patient's underlying AML or breast cancer involvement of bone.

IMPRESSION:

1.  Increased DWI signal involving the bilateral medial thalami, bilateral mammillary bodies and periventricular white matter of the third ventricle, with corresponding T2 prolongation in these regions as well as within the the periaqueductal gray. Given this constellation of findings, the possibility of Wernicke's encephalopathy should be considered, and correlation for thiamine deficiency is recommended.

2.  Diffusely markedly decreased and heterogeneous T1 marrow signal, either secondary to marrow rebound or diffuse infiltration from underlying malignancy.