Case Notes
History
55 yo male with prior head CT revealing multiple calcific cystic lesion and normal ventricular size for chronological age. There had been a previous suboccipital craniotomy with partial removal of a lower pontomedullary cyst. Five months later the patient developed increasing headaches and CT evidence of internal obstructive hydrocephalus. The patient underwent a right VP shunt and midline suboccipital craniotomy for drainage of a sizable pontine cavernous malformation.Exam
MR flair
Prior Study
CT Head pre contrast1. Multiple brain cavernous angiomas.
2. Evidence of internal type of hydrocephalus with block likely at the outlet of the fourth ventricle.
3. Prior suboccipital craniotomy for drainage of a lower brain stem cyst.
T1-w MR pre contrast
1. In the interim since the recent head CT, There has been placement of a right temporal VP shunt and surgical evacuation of the caudal part of the pontomedullary cavernous malformation. The ventricular size has decreased only partially compared to the CT suggesting the shunt may not be fully functional.
2. The larger cavernous angioma's in the left parietal vertex and mid pons residua both contain T1 hyperintense internal blood products. The other non cystic cav-mals are difficult to see on T1-w sequences.
MR T2-w spin echo
1. Four out of five of the cavernous angiomata on CT are evident on T2 MR.
2. Given there is residual hydrocephalus and that the VP shunt catheter is stretching the septum pellucidum, it is possible the septum pellucidum may be partially obstructing the distal catheter tip.