 Again seen are postoperative findings related to right transfrontal laser ablation of tumor centered at the right thalamus and midbrain. Lack of contrast limits comparison however there appears to be minimal increase in size of the tumor, for example measuring approximately 3.1 cm in the transverse dimension on the coronal T2 sequence, previously 2.8 cm, and 3.0 cm in the craniocaudal dimension, previous 2.4 cm. The tumor enlargement is more notable when compared to prior MRI from 4/3/2016 when the lesion measured approximately 2.0 x 1.8 mm cm the transverse and craniocaudal dimensions measured with a similar technique on the coronal T2 sequence. Extent of surrounding vasogenic edema extending to the brainstem and cerebellum as well as the right temporal and parietal lobes is mildly decreased. There is effacement of the third ventricle and leftward displacement measuring approximately 7 mm and similar to prior. No significant midline shift more superiorly. No uncal herniation. Blood products within the tumor are again evident with evolution and slight decrease in conspicuity. No evidence of acute infarct. There is layering debris in the right occipital horn most evident on the diffusion sequence which while nonspecific may represent pus. Foci of susceptibility in the left occipital horn are compatible with blood products. Periventricular FLAIR hyperintensity reflecting transependymal CSF flow is much improved since prior MRI. Ventricular dilatation is similar to prior MRI from 5/21/2016, but note ventricular dilatation on CT from same day was worse since CT from 6/8/2016. Left frontal EVD in place.CSF flow sequence demonstrates biphasic flow anteriorly in the prepontine cistern which extends to the suprasellar cistern but without evidence of flow extension into the third ventricle through the third ventriculostomy. 3-D T2 sequence demonstrates dilated third ventricular recesses. Partially empty sella.
1. Right thalamic/midbrain metastasis is suboptimally evaluated without contrast but appears minimally larger than 5/21/2016 and more clearly larger compared to 4/3/2016. Surrounding vasogenic edema is improved. Ventricle size is similar to same-day CT but larger since CT dated 6/8/2016. Left transfrontal EVD in place. Third ventriculostomy does not appear to be patent.2. Lack of contrast limits evaluation for intracranial infection. There is layering debris with restricted diffusion in the right occipital horn, which is nonspecific in the setting of intraventricular blood products, but may represent pus and can be correlated with CSF analysis. No evidence of intracranial abscess or empyema.