Case 30 - Toxic Leukoencephalopathy: 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 AND ORBITS W/WO CONTRAST

INDICATION: new onset of right eye diplopia. History of primary CNS lymphoma with relapse on cycle 6 of methotrexate

TECHNIQUE: Multiplanar multisequence magnetic resonance images of the brain and orbits without and with intravenous contrast.

COMPARISON: 4/27/2020, 03/01/2020, 2/21/2020

FINDINGS:

Interval development of diffuse confluent primarily subcortical T2/FLAIR signal abnormality throughout the centrum semiovale bilaterally primarily involving the frontoparietal regions. Posteriorly, there is some extension along the periatrial periventricular white matter extending into the temporal lobes. FLAIR signal abnormalities also noted within the cerebellum involving the dentate nuclei. There is no associated enhancement. The ventricles appear similar in size without significant effacement. There are very subtle patchy areas of hazy low signal on the ADC maps.

Prior left temporal craniotomy. Again noted is slightly decreasing enhancement within the left temporal lobe posteriorly with slightly decreased associated vasogenic edema when compared to 4/27/2020. No new areas of enhancement are seen.

Optic nerves appear symmetric in signal and caliber without abnormal enhancement or signal abnormality. The extraocular muscles are intact. There is no retrobulbar pathology. The globes appear symmetric.

Remainder of the examination is stable. Small lacunar infarct in the right midbrain. Paranasal sinuses clear. No masses or effusions. The signal appears to be within normal limits.

IMPRESSION:

Compared to 4/27/2020, interval development of confluent T2/FLAIR signal abnormality primarily within the centrum semiovale and dentate nuclei without mass effect or enhancement. Findings are concerning for toxic leukoencephalopathy, likely methotrexate induced. Differential diagnosis includes posterior reversible encephalopathy syndrome and progressive multifocal leukoencephalopathy but the white matter pattern is more compatible with methotrexate leukoencephalopathy.

Left temporal craniotomy with continued decrease in enhancement and vasogenic edema on the left posterior temporal lobe.

Unremarkable evaluation of the orbits and optic nerves without focal abnormality.