Obstructive hydrocephalus. Status post neurocytoma resection 3 months ago. There has been evolution of the postoperative changes since the previous examination. Foci of diffusion restriction in the surgical bed and along the right transparietal surgical tract are improved and probably reflect residual blood products and other postoperative change. Right frontal infarct and edema have evolved, with less extensive white-matter T2-hyperintensity with associated overlying cortical laminar necrosis. There is a linear surgical tract in the left frontal lobe from previous biopsy.The right transparietal ventriculostomy catheter has been removed and the tract is larger than before which probably reflects evolution of the ischemic changes along the tract. There is also T2-hyperintensity along the right parietal surgical tract, probably gliosis given previous postoperative findings. There is new significant focal expansion of the posterior parts of the right lateral ventricle and its temporal horn, which is probably caused by adhesions in the posterior body. The anterior right lateral ventricle is unchanged. The third and left lateral ventricle are mildly more expanded than previously but are not particularly dilated. Small amount of residual heterogeneous tumor along the roof of the right lateral ventricle is probably present as described before. It was compressed previously by blood and other postoperative change, and has now emerged as an oval area of abnormality. Foci of susceptibility effect in the ventricles, along the tentorium and in the surgical cavities are reflective of blood products. There is mild contrast enhancing dural thickening underlying the craniotomy flaps, within expected. There is minimal, somewhat linear contrast enhancement in the right transparietal surgical tract, which is probably postoperative in nature relating to granulation tissue. The major cerebral flow voids are intact. Severe mucosal thickening completely opacifies the right maxillary sinus. There is also mucosal thickening involving the right anterior ethmoid sinuses and the hypoplastic right frontal sinus.
1.Expected evolution of the postoperative findings in the right frontal and parietal lobes.2.Following removal of the right transparietal ventriculostomy catheter, there has been interval focal dilatation of the right lateral ventricle posterior to presumed adhesions in the posterior body.3.An area of oval residual tumor has now emerged along the roof of the right lateral ventricle.