Findings
Linear T2 hyperintensity is seen across bilateral frontal lobes, extending to the frontal horns of the lateral ventricles, on the left related to prior ventricular catheter tract and on the right related to recent endoscopic third ventriculostomy. Small amount of restricted diffusion is seen along the tract is indicating small amount of cytotoxic edema. On the right, this involves a portion of the right caudate head. There is also an additional linear T2 hyperintense tract slightly more posteriorly which may be secondary to prior intervention; this was present on the study of 9/12/2011. There is no large territorial infarct identified. There is no lobar hemorrhage. No extra-axial collection is seen. There is a tiny amount of intraventricular air related to recent surgery. Dependent probable blood products are seen within the occipital horns of the lateral ventricles bilaterally. Ventricular caliber is unchanged compared to the recent CT examination.
The tectal mass is unchanged in appearance compared to the prior MRI. There is persistent obstruction of the lower portion of the cerebral aqueduct.
There is a defect seen within the floor of third ventricle. Phase contrast images demonstrate minimal biphasic flow through the ventriculostomy defect. There is biphasic flow seen at the foramen magnum, and the fourth ventricle outflow tract. No flow is seen through the cerebral aqueduct. Prior findings of suboccipital craniectomy are again noted.
Impressions
- Postoperative changes following endoscopic third ventriculostomy with tiny amount of biphasic flow through the ventriculostomy defect. Ventricular size unchanged from prior CT.
- Unchanged tectal mass obstructing the distal cerebral aqueduct with lack of CSF flow through the aqueduct.
- Findings of prior suboccipital craniectomy.