CT Ventriculography for diagnosis of occult ventricular cysticerci

Abstract

Background: Neurocysticercosis is the most common parasitic infection of the central nervous system (CNS). Intraventricular lesions are seen in 7-20% of CNS cysticercosis. Intraventricular lesions can be missed by computed tomography (CT) and magnetic resonance imaging (MRI) as they are typically isodense/isointense to the cerebrospinal fluid. We present our experience with CT ventriculography to visualize occult cysts.

Case description: Two patients presented with hydrocephalus and suspected neurocysticercosis were evaluated with CT and MRI with and without contrast failing to reveal intraventricular lesions. CT-ventriculography was used: 10 ml of cerebrospinal fluid was drained from the ventriculostomy catheter, and 10 ml of iohexol 240 diluted 1:1 with preservative-free saline was injected through the ventriculostomy catheter. Immediate CT of the brain was performed. The first patient had multiple cysts located throughout the body of the left lateral ventricle. The second patient had a single lesion located in the body of the lateral ventricle. The CT-ventriculography findings helped in identifying the lesions and plan the surgical intervention that was performed with the aid of an endoscope to remove the cysts.

Conclusions: Intraventricular neurocysticercosis is a common parasitic disease which can be difficult to diagnose. We used CT-ventriculography with injection of contrast through the ventriculostomy catheter in two patients where CT and MRI failed to demonstrate the lesions. This technique is a safe and useful tool in the imaging armamentarium when intraventricular cystic lesions are suspected.

Keywords: Intraventricular cyst; hydrocephalus; neurocysticercosis; ventriculography.

Figure 1

Case #1. (a): Axial T1 weighted magnetic resonance imaging of the brain without contrast showing no intraventricular lesions. (b): Axial T2 weighted magnetic resonance imaging showing ventriculostomy catheter in the body of left lateral ventricle.

Figure 2

Case #1. (a): CT scan of the brain without contrast showing L frontal ventriculostomy in lateral ventricle. (b): CT scan of the brain during injection of intraventricular iohexol showing multiple lesions in the body of the left lateral ventricle.

Figure 3

Case #2. (a): Axial T1 with contrast magnetic resonance imaging of the brain showing enhancement in right lateral ventricle without evidence of intraventricular cysts. (b): Axial T2 weighted magnetic resonance imaging of the brain showing right ventriculostomy catheter in the lateral ventricle. No intraventricular cysts were seen.

Figure 4

Case # 2. (a): Axial CT scan of the brain without contrast showing right ventriculostomy catheter in the lateral ventricle. (b): Axial CT scan of the brain with ventricular injection of iohexol showing the outline of the right ventricular lesion.