Case 32 - Herpes Encephalitis: 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.

EXAMINATION: MRI brain with and without contrast.

CLINICAL HISTORY: HSV encephalitis with hydrocephalus status post lumbar drain.

TECHNIQUE: Multiplanar multisequence MRI images of the brain performed following administration of 10 cc of Gadavist.

COMPARISON: MRI brain and IACs, 7/31/2019.

FINDINGS:

Compared to 7/31/2019, there is increased T2 FLAIR signal hyperintensity involving the cortex and subcortical white matter of the right temporal lobe, right insula, and left medial temporal lobe as well as the right cingulate gyrus. Redemonstration of loss of lack of FLAIR suppression within the subarachnoid spaces of the supratentorial brain, particularly over the right cerebral convexity.

There is a punctate focus of restricted diffusion in the right centrum semiovale with associated FLAIR signal hyperintensity. Additional smaller subependymal foci of restricted diffusion within the posterior body of the left lateral ventricle with suggestion of layering fluid within the posterior horn of the left lateral ventricle appears similar to prior.

Decreasing size of a right of a subdural fluid collection measuring up to 5 mm in depth over the right temporal occipital region.

Prior right frontal approach ventriculostomy catheter has been removed with mild enhancement along the catheter tract. Overall the lateral ventricles appear decreased in size since prior MRI on 7/31/2019, with superimposed mild effacement of the right lateral ventricle. On phase contrast CSF flow study, there is robust biphasic CSF flow related signal ventrally and dorsally at the foramen magnum and within the cerebral aqueduct and fourth ventricle.

Diffuse pachymeningeal enhancement unchanged with increasing areas of leptomeningeal enhancement within the right insula and right anterior temporal lobe.

Mild to moderate periventricular and subcortical white matter T2 FLAIR hyperintensities, nonspecific.

No new acute intracranial hemorrhage. No midline shift. Major intracranial flow voids are preserved.

Status post left suboccipital craniotomy the setting of prior residual schwannoma resection with unchanged extra-axial collection lateral to the left cerebellum measuring up to 1.5 cm in thickness with mild mass effect.

Mucosal thickening of the ethmoid air cells with layering debris in the maxillary sinuses. Large right and moderate left facet effusions. Orbits are normal.

IMPRESSION:

1. Increasing FLAIR hyperintensity within the right greater than left temporal lobes and right insula as well as right cingulate gyrus compatible with HSV encephalitis. Developing cortical laminar necrosis at the right anterior temporal lobe. Mild effacement of the right lateral ventricle.

2. Few punctate areas of restricted diffusion involving the right periventricular white matter likely represent small areas of microvascular ischemia.

3. Mild decrease in caliber of the supratentorial ventricles with removal of the right frontal approach ventriculostomy catheter since 7/31/2019. Redemonstrated fluid layering in the posterior horn of the left lateral ventricle and ependymal diffusion restriction suggesting associated ventriculitis.

4. Diffuse pachymeningeal enhancement unchanged, with additional leptomeningeal enhancement in the right temporal lobe and right insula. These can be related to ongoing meningeal inflammation.

5. Decreasing size of a right of a subdural fluid collection measuring up to 5 mm in depth over the right temporal occipital region.

6. Status post left suboccipital craniotomy for prior vestibular schwannoma resection. Unchanged left lateral cerebellar extra-axial collection.