Once again, there is a 1.5 cm lesion is seen in the left pontine-middle cerebellar peduncle junction with surrounding susceptibility artefact. The lesion enhances. No intrinsic high T1 signal will surrounding oedema to suggest recent haemorrhage.This is in keeping with a cavernoma without evidence of recent haemorrhage.
A well-defined 2.5 cm lesion is in the roof of the fourth ventricle just left of the midline. This lesion demonstrates high T2 signal which incompletely fluid suppresses. It is of low signal on T1 weighted imaging. It does not enhance. Increased signal on DWI without corresponding decreased ADC values. The lesion partly effaces the fourth ventricle without evidence of obstructive hydrocephalus.
MRS performed over the 4th ventricular roof lesion shows no elevated cho/cr to particularly favour tumour. There is probable mild reduction of NAA and mild elevation of lactate peak, nonspecific.
Perfusion shows a subtle rim of increased CBV surrounding this lesion; correlation with recent MRA shows that this rim is due to the presence of small peripheral vessels.