gms | German Medical Science

Objective: Intraoperative imaging helps to achieve immediate information about blood vessels and critical impairment of brain perfusion during vascular neurosurgery. The current prospective study analyzed advantages/drawbacks of intraoperative CT-angiography (iCTA) and near-infrared indocyanine green videoangiography (ICGA) in comparison to each other during intracranial aneurysm clipping.

Methods: Patients (n=10) received ICGA using surgical microscopes with integrated ICGA technology (Zeiss, Jena/GER; Möller-Wedel, Wedel/GER) before and immediately after aneurysm clipping. Patients were then scanned with a 40-slice-sliding-gantry-CT (Siemens, Forchheim/GER), a dynamic perfusion CT was followed by iCTA. The purpose of either or both intraoperative imaging techniques was the detection of vascular patency of major arteries, imaging of arising perforating arteries and brain perfusion after clip application. Quality of each imaging was assessed in a blinded consensus reading by an experienced neurosurgeon/neuroradiologist.

Results: The quality of all imagings was rated "excellent" or "good" with one exception and therefore eligible for analysis of informative value of each imaging technique. ICGA was able to visualize blood flow and vascular patency of all major vessels and perforating arteries within the visual field of the microscope but failed to display any vessels beyond it. Even little covering with brain parenchyma impaired detection of vessels. ICTA was of “good” or “excellent” quality in all cases of clipped aneurysms. In one case of a previously coiled recurrent aneurysm, iCTA was not sufficiently evaluable due to additional coil artifacts. Small, perforating arteries could not be detected with iCTA, which however reached good visualization of the global blood flow and brain perfusion in “good” or “excellent” quality being sufficient for intraoperative decision making.

Conclusions: Combination of ICGA and iCTA is feasible with very good diagnostic imaging quality associated with short acquisition time and little interference with surgical workflow. They are complementary techniques which help to assess information about local (ICGA/iCTA) as well as global (iCTA) cerebral perfusion immediately after aneurysm clipping. Intraoperative perfusion maps by iCTA help to detect clipping-related perfusion deficits allowing for immediate clip repositioning. The impact of the combination of these methods on patients’ outcome now has to be analyzed prospectively in a larger series.