Neuroradiology Case of the Week

Case 18

Ramon de Guzman, MD, P-L Westesson, MD, PhD, DDS,
Jose Echeverri, MD,and Larry Buadu, MD, PhD

Clinical Presentation: The patient is a 40-year-old man who presented with severe headache followed by loss of consciousness. Initial head CT scan showed subarachnoid hemorrhage at the suprasellar cistern. A ventriculostomy catheter was inserted via right frontal approach. Angiography showed dissection of the right vertebral artery resulting in a pseudoaneurysm involving the origin of the right posterior inferior cerebellar artery and a stenting procedure was done. Ventriculostomy catheter was removed and a new catheter was placed via a left frontal approach. Follow-up CT scan showed a focal intraparenchymal hemorrhage with surrounding edema in the right frontal lobe secondary to previous catheter placement. Several angiograms were performed to evaluate status of the stent within the right vertebral artery. Patient’s clinical condition worsened with findings of meningitis.

Radiographic Findings: The contrast enhanced CT scan of the head showed enhancement of the ependymal lining of the lateral ventricles (Fig. 1).

Figure 1: CECT shows enhancement of the ependymal lining of the lateral ventricles (arrows).

Diagnosis: Ventriculitis (Ependymitis)

Discussion:
Clinical Discussion
   Ventriculitis or ependymitis usually follows shunting procedures, intraventricular surgery, placement of indwelling prosthetic devices, intrathecal chemotherapy or meningitis [1]. Organisms are introduced into the ventricle as a result of bacteremia from abscess, trauma or instrumentation of the ventricle. Microbiology examination revealed oxacillin-resistant staphylococcus aureus in this case.

Neuro Imaging Discussion
   Diffusely thickened, intensely enhancing ependyma is seen on contrast-enhanced MR scans1 and contrast enhanced CT scan. The key to the diagnosis is subependymal enhancement. Enhancement of the ependyma is also observed in lymphoma (the most likely diagnosis in patients infected with human immunodeficiency virus with subependymal enhancement) and other malignant lesions with subependymal spread [2].

References:

1. Barloon TJ, Yuh WTC, Knepper LE et al: Cerebral Ventriculitis, MR findings, J Comp Asst Tomography 14:272-275, 1990.
2. Grossman RL, Yousem DM (eds). Neuroradiology, The Requisites. Chapter 6:180. St. Louis, Mosby, 1994.