Image guidance in neurosurgery: Flatpanel-Detector Parenchymal Blood Volume imaging and Magnetic Resonance - Dynamic Contrast Enhanced perfusion imaging in meningiomas

The Hybrid - Operating Room (OR) at the Radboudumc is equipped with a robotic
Flatpanel Detector - CT (FP-CT) which facilitates innovative image guided
interventions. This FD-CT can provide peri-operative feedback on cerebral
hemodynamics and is a potential valuable and easy technique for image guidance
in neurosurgery and minimally invasive interventions. As FP-CT has been studied
extensively in healthy subjects and stroke patients, this study will be an
important step towards image guidance in the focal treatment and removal of
brain tumors.

The primary objective of this clinical pilot study is to explore the
feasibility of Flatpanel Detector - Parenchymal Blood Volume (FD-PBV) imaging
in patients with intracranial meningiomas during neurosurgery in the Hybrid-OR.
Image quality, added value in neurosurgery and workflow/logistics will be
evaluated. Image quality and hemodynamic parameters will be compared with
Magnetic Resonance - Dynamic Contrast Enhanced (MR-DCE) perfusion imaging.

This is an explorative prospective clinical pilot study. MR-DCE perfusion
imaging will be added to the standard pre-operative MRI used for
neuro-navigation in neurosurgery. In seven patients, FD-PBV imaging will be
performed at the day before surgery. These patients are awake. The last three
patents will be scanned while under general anesthesia, with the skull fixated
in a carbon head clamp to assess the influence of positioning of the head and
the radiolucent carbon head clamp used during surgery.

The overall burden for patients in this study consists of an extension of the
already performed MR scan, and one FD-PBV imaging acquisition at the day of
surgery. The MR perfusion scan will be combined with the standard-of-care MR
neuro-navigation performed 1 to 3 days before the surgery, effectively adding 5
minutes. FD-PBV acquisitions will be done at the Hybrid-OR. In 7 patients this
will be done while they are awake, in 3 patients this will be done while under
general anaesthesia, right after fixating the head in the head clamp. For these
three patients, time spent under general anaesthesia will be prolonged ~15
minutes.

All contrast agents will be administered intravenously; contrast dose for the
MRI will be increased from 15 ml to 27,5 ml of gadolinium chelate (Dotarem) and
total contrast load for FD-PBV imaging is 80 ml of 300 mg/ml iodinated contrast
(Iomeprol). Total effective radiation exposure of FD-PBV imaging will be
1.6-3.0 mSv (depending on positioning of the head and presence/absence of the
carbon head clamp). Effective doses are confirmed by the manufacturer,
literature reports and in house dose measurements.

There are no direct benefits for patients participating in this study. As the
feasibility of cerebral FD-PBV imaging has already been demonstrated in healthy
patients and a variety of cerebrovascular diseases in the angiographic room,
further research exploring intra-operative applications has to be performed in
neurosurgical patients. Results of this study will be used to improve image
guidance in neurosurgery and minimally invasive interventions including focal
treatment of brain tumors and deep brain stimulation.