Female, 38 years old, with Chiari malformation status post decompression with pseudomeningocele and CSF leak, recently admitted for infection involving the ventricular shunt and pseudomeningocele, status post EVD placement and removal, status post pseudomeningocele/abscess drainage and repair. Evidence of Chiari decompression status post redo is seen including suboccipital craniectomy and resection of the posterior arch of C1. The cerebellar tonsils prolapse into the widened foramen magnum with some crowding of the dorsal CSF space. Ventrally, there seems to be adequate CSF patency. The brainstem demonstrates a somewhat kinked morphology appearing drawn towards or perhaps tethered to the dorsal dural surface of the neo-foramen magnum. On cine flow images, biphasic CSF flow is seen through the ventral foramen magnum, but there is no significant flow dorsally. A previously seen thin midline fluid collection at the craniectomy site has completely or nearly completely resolved leaving behind a band of solidly enhancing tissue which likely represents granulation tissue and scarring.A small cystlike area of encephalomalacia affecting the right genu of the corpus callosum and adjacent parenchyma is probably unchanged when compared to prior CT examinations. Diffusion restriction and susceptibility effect within this lesion may reflect the presence of aging blood product. Sequelae of prior right frontal approach ventriculostomy catheter placement are seen. There is T2 hyperintensity along the prior catheter tract which may reflect gliosis or mild residual edema. The ventricles are dilated, similar to that seen on recent prior CT examinations. T2 hyperintensity is seen in the periventricular tissues, particularly at the frontal horns and the occipital horns.Elsewhere, no diffusion restriction or focal parenchymal edema is observed. A few scattered small foci of parenchymal T2 hyperintensity are nonspecific. No evidence of acute intracranial hemorrhage is seen. No pathologic parenchymal or extra-axial enhancement is observed.
1.Postoperative findings are seen compatible with Chiari decompression status post redo. The dorsal CSF space at the neoforamen magnum remains crowded and there is no detectable CSF flow in this location. Ventrally, the CSF space seems to be adequately patent. The brainstem demonstrates a somewhat kinked morphology suggesting tethering or adhesion to the dorsal thecal sac.2.The previously demonstrated infected pseudomeningocele has been repaired. Little if any actual fluid remains, and the involved tissue demonstrates findings compatible with granulation and scarring.3.Parenchymal injury along the genu of the right corpus callosum is perhaps related to prior ventriculostomy placement and/or infection. Signal abnormally along the prior ventriculostomy tract may reflect gliosis or mild residual edema.4.The ventricles remain dilated but similar to recent prior CT's. T2 hyperintensity in the periventricular tissues at the frontal and occipital horns may indicate transependymal CSF flow or perhaps the sequelae of prior infection.