Intraorbital access using fluoroscopic flat panel detector CT navigation and three-dimensional MRI overlay

Flat panel detector CT (FD-CT), three-dimensional image overlay and navigation software on contemporary fluoroscopic units generate less radiation dose while performing imaging of comparable quality to conventional CT. They can superimpose MR and CT datasets and can accurately guide percutaneous procedures providing live instrument visualization and the capability of re-imaging without patient transfer. These techniques, however, have been minimally used for accessing the head.

Using an Allura Xper FD20 unit (Philips Healthcare Andover, Massachusetts, USA), three-dimensional image overlay and FD-CT navigation were used for percutaneous n-butyl cyanoacrylate (nBCA) embolization of an intraorbital mass in a 69-year-old man.

Three-dimensional image overlay provides accurate anatomical relationships between the optic nerve and vascular portions of the mass. Percutaneous nBCA was technically successful without non-target embolization and with no significant bleeding encountered during operative resection.

FD-CT navigation and three-dimensional image overlay provide accurate instrument guidance and spatial resolution comparable with current neuro-navigation systems while also providing real time instrument position and the ability to re-image without moving the patient. These are features not available with other types of neuro-navigation.