gms | German Medical Science

Objective: 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this study, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of occlusion and vessel patency was assessed in patients, who underwent surgery for intracranial aneurysms, cerebral arteriovenous malformations and arteriovenous fistulas.

Methods: 17 patients were included in this retrospective analysis (12 intracranial aneurysms, 2 arteriovenous malformations, 3 dural arteriovenous fistulae). Prior to surgery, a 360° rotational fluoroscopy scan was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac® workstation, subtracted and reconstructed using OsiriX® free software. The procedure was repeated after clip placement/occlusion. Both image sets were compared for assessment of occlusion and vessel patency.

Results: Image acquisition and contrast administration caused no adverse effects. In both patients with cerebral arteriovenous malformation, 3D fluoroscopy with intravenous contrast administration resulted in good image quality. Preoperative embolization with Onyx produces significant artifacts that can be largely removed by simple digital subtraction techniques. In aneurysm patients, the image quality was sufficient to follow the patency of the vessels distal to the clip. Precise image subtraction and post-processing can reduce metal artifacts and make the clip-site assessable and depict larger neck-remnants.

Conclusion: This technique quickly supplies intraoperative images of adequate quality to locate vascular pathologies. However, it does not produce dynamic images. Thus, early draining veins cannot be located unless anatomically identified, based on the preoperative DSA. In this case, it can be used for intraoperative obliteration control. This technique quickly supplies images at adequate quality to evaluate distal vessel patency after aneurysm clipping. At the momentary state of this technology, it cannot replace postoperative conventional angiography. However, 3D fluoroscopy and image post-processing are young technologies. Further technical developments are likely to result in improved image quality.