Image guided aneurysm surgery in a Brainsuite® ioMRI Miyabi 1.5 T environment

Current literature only gives sparse account of aneurysm surgery in an intraoperative MRI environment. After installation of a BrainSuite(®) ioMRI Miyabi 1.5 T at our institution the aim of the present preliminary study was to evaluate feasibility, pros and cons of aneurysm surgery in this special setting.

Since February 2009, during a 3 months period we performed elective image guided aneurysm surgery in 4 ACM and 1 ACOM aneurysm (four patients) in this ioMRI setting. The patients' heads were rigidly fixed in the Noras 8-Channel OR Head Coil. Our imaging protocol included MP-RAGE, T2-TSE axial, TOF-MRA and diffusion-/perfusion-imaging immediately before surgery and after clip application. Presurgical 3D-planning was performed using the iPlan®-Software.

All five aneurysms were operated without temporary clipping. There were no intra- or postoperative complications. Patient positioning and head fixation with the integrated Noras Head Clamp was feasible, but there were significant limitations particularly with regard to more complex approaches and patient physiognomy. Image quality especially TOF-MRA was good in 4, insufficient in 1 aneurysm. Presurgical planning especially vessel extraction from TOF-MRA was possible but certainly needs significant future improvement. Diffusion- and perfusion weighted examinations yielded good image quality.

Our limited experience is encouraging so far. Further improvement particularly concerning flexibility of patient positioning and presurgical 3D-planning for vascular procedures is most necessary. As a future perspective image guided aneurysm surgery in an ioMRI-environment may be helpful especially in complex aneurysms and provide neurosurgeons and neuroanaesthesiologists with additional information about cerebral haemodynamics and perfusion pattern in the vascular territory distal to the target vessel.