 Brain:Again seen are extensive postsurgical changes involving the calvarium including left and posterior calvarial cranioplasty as well as a suboccipital craniectomy and cranioplasty, better seen on prior CT. Again seen is a right posterior approach shunt catheter which courses within the right lateral ventricle and terminates near the callosal body. A stent is again seen extending between the cerebral aqueduct and dorsal subarachnoid space at the foramen magnum. The right lateral and third ventricles remain slitlike, unchanged. The left lateral ventricle is relatively larger but not particularly dilated and unchanged since 2/3/2014. The fourth ventricle remains enlarged, unchanged in extent, partially on an ex-vacuo basis secondary to encephalomalacia involving the inferior cerebellar hemispheres (right greater than left) and vermis. The degree of T2 and flair signal alteration involving the cerebellar hemispheres and vermis is stable. No areas of diffusion restriction is seen to suggest an acute ischemic event. There is high T2/FLAIR signal involving the bilateral cavernous sinuses extending into the bilateral tentorium favored to represent dural thickening/venous engorgement related to chronic shunting, and more pronounced when compared to more remote studies dating back to 2009. There is FLAIR hyperintensity along the surface of the left temporal lobe, which is new since 2/3/2014 MRI and may represent gliosis related to prior left-sided craniotomy and/or adjacent extra-axial collection seen on CT from March 20, 2014.CSF flow study redemonstrates biphasic flow anteriorly at the foramen magnum with no discernible CSF pulsation posteriorly, similar to the prior examination. As before, no definite evidence of CSF flow pulsation through the cerebral aqueduct, within the fourth ventricle, or through the stent. High-resolution 3-D T2 sequence also demonstrates focally diminished CSF space dorsally at the foramen magnum.Cervical spine: Motion degradation on the current and prior studies limit assessment, but there appears to be slight increase in size of the cervical syrinx at the C2 and C3 levels. The more inferior aspect of the syrinx extending from C4 to C7 is not appreciably changed and measuring approximately 10 x 9 mm at the C5-C6 level.A central disk protrusion asymmetric to left is present at C6-C7 with ligamentum flavum thickening similar to prior. Right paracentral disc protrusion at C7/T1 is also similar in appearance to the prior examination. There remains mild spinal canal stenosis from C5-C6 to the C7-T1 levels as before.
1. Compared to MRI brain dated 2/3/2014 there is no significant change in appearance of the posterior fossa with evidence of prior Chiari decompression, fourth ventricular stent, as well as effaced CSF spaces and diminished flow dorsally at the foramen magnum.2. No significant change in size of the ventricular system without evidence of hydrocephalus. Unchanged slitlike right lateral ventricle and relatively larger left lateral ventricle. 3. Again seen is a cervical syrinx. Compared to 2/3/2014, there appears to be mild increase in size of the syrinx component at the C2 and C3 levels. The more inferior aspect of the syrinx which is larger extending from C4 to C7 is not significantly changed.4. Please see additional details above.