Seeing Floaters: A Case Report and Literature Review of Intraventricular Migration of Silicone Oil Tamponade Material for Retinal Detachment.

BACKGROUND: Intraocular injection of silicone oil is commonly performed during vitrectomy to tamponade the retina in place for treatment of retinal detachment. Although rare, this intravitreal silicone can migrate through the optic nerve and chiasm and enter the cerebral ventricles. CASE DESCRIPTION: Here we present a case report of a patient presenting with headache and intraventricular hyperdensities on a computed tomography (CT) scan, raising a concern for intraventricular hemorrhage. However, the intraventricular hyperdensities were in a nondependent location and moved to a new nondependent location when repeat imaging was performed with the patient in the prone position. We provide a literature review of this phenomenon and discuss the relevant CT and magnetic resonance imaging findings. CONCLUSIONS: Intraocular silicone can rarely migrate into the cerebral ventricular system. Careful review of the clinical history and imaging findings can help distinguish this from other, more dangerous intracranial pathologies.

Noncontrast dynamic 3D intracranial MR angiography using pseudo-continuous arterial spin labeling (PCASL) and accelerated 3D radial acquisition.

PURPOSE: To develop a novel dynamic 3D noncontrast magnetic resonance angiography (MRA) technique that combines dynamic pseudo-continuous arterial spin labeling (dynamic PCASL), accelerated 3D radial sampling (VIPR), and time-of-arrival (TOA) mapping to provide quantitative assessment of arterial flow. MATERIALS AND METHODS: Digital simulations were performed to investigate the effects of acquisition scheme and sequence parameters on image quality and TOA mapping fidelity. Five patients with vascular malformations (arteriovenous malformation [AVM] = 3, dural arteriovenous fistula [DAVF] = 2) were scanned and the images were compared to digital subtraction angiography (DSA) for the ability to identify the arterial supply, AVM location, nidus size, and venous drainage. RESULTS: Digital simulations demonstrated reduced image artifacts and improved TOA accuracy using radial acquisition over Cartesian. TOA mapping accuracy is more sensitive to sampling window length than time spacing. Dynamic PCASL MRA depicted seven of eight arterial pedicles, and accurately measured the AVM nidus size when the nidus was compact. The venous drainage in the AVM patients was not consistently visualized. CONCLUSION: Dynamic 3D PCASL-VIPR with TOA mapping is able to acquire both high temporal and spatial resolution inflow dynamics that could improve diagnosis of high-flow intracranial vascular diseases.