252. True FISP Cardiac Gated CSF Flow Dynamic Imaging of Membranes, Veils, and Cysts in the CNS

Authors: Alon H. Kashanian; Moise Danielpour, MD (Los Angeles, CA)

Introduction:

The qualitative non-invasive monitoring of cerebrospinal fluid (CSF) dynamics and brain pulsatility has critical clinical relevance in the management of patients with hydrocephalus and other CSF disorders. Currently, non-invasive phase-contrast MRI and cine echo-planar imaging are used extensively, but lack a detailed spatial and temporal resolution needed to adequately demonstrate brain pulsations and movements of intracranial structures. Electrocardiographic (ECG)-gated true fast imaging with steady-state precession (FISP) sequences is widely used to investigate cardiac motion. We investigated the utility of this imaging technology in demonstrating brain pulsations and CSF dynamics. We feature here the application of true FISP cardiac-gated imaging to the diagnosis and management of membranes, veils, and cysts in 6 children.

Methods:

Six symptomatic children with existing posterior fossa pathology, including Chiari malformation, syringohydromyelia, and intraventricular hemorrhage, underwent radiological investigation with true FISP cardiac-gated imaging at our institution.

Results:

True FISP imaging successfully identified the presence of membranes, veils, or cysts in 6 patients. While conventional imaging studies failed to demonstrate the presence or movement of these structures, true FISP allowed for dynamic visualization of these structures as well as surrounding impression of CSF flow. In our patients with Chiari malformation, T1 and phase-contrast cine MRI appeared to demonstrate obstruction of CSF flow secondary to tonsillar herniation, whereas true FISP showed patent peritonsillar CSF flow and the presence of a pulsatile arachnoid veil, subsequently confirmed during open surgery.

Conclusion:

We demonstrate six patients where true FISP cardiac-gated imaging was very instructive in visualizing dynamic images of membranes, veils, and cysts of the CNS. We advocate use of this technology as we believe it will aid in pre- and post-surgical decision making by providing a more complete image of posterior fossa pathology.