A large intraventricular mass is seen within the right lateral ventricle in the region of the foramen of Monro measuring 27.2 x 15.5 x 23.1 (AP x W x H) mm. This is hyperintense on both FLAIR and T2 weighted imaging with some focal cystic areas which follow CSF. The lesion is isointense on T1 weighted imaging with no contrast enhancement. No susceptibility artefact is seen and no calcification is identified on retrospective review of the CT brain.
There is asymmetry of the lateral ventricles with dilatation of the right temporal horn suggesting a degree of ventricular entrapment. Periventricular signal change is felt more likely to represent small vessel ischaemia rather than transependymal oedema. The basal cisterns appear unremarkable.
The cerebellar tonsils have a PEG like configuration and extent proximally 9.5 mm below the foramen Magnum. Remaining posterior fossa structures, mid brain and corpus callosum appear unremarkable. No syringohydromyelia is identified in the upper cord.
- Right lateral ventricle intraventricular mass most likely represents a subependymoma or central neurocytoma. Ependymoma is felt unlikely given the lack of enhancement. Mild dilatation of the right lateral ventricle suggests a degree of outflow obstruction. This appears stable compared to the previous CT brain.
- Changes consistent with a Chiari I malformation.
- MRI (MR Perfusion):