Postoperative three-dimensional CT angiography (3D-CTA) in evaluation of proximal clipping for ruptured vertebral aneurysms

At present, intra-arterial angiography remains the gold standard for most cerebrovascular problems. Recently, three-dimensional computed tomographic angiography (3D-CTA) has been reported as a screening method for the diagnosis of cerebrovascular disease. This imaging modality uses the information obtained on a contrast-enhanced CT scan to generate three-dimensional images of the cerebrovascular system. We performed 3D-CTA in the preoperative and postoperative evaluation of patients undergoing proximal clipping of ruptured vertebral artery aneurysms in addition to conventional cerebral angiography. In this study, the value of SD-CTA after proximal clipping of ruptured vertebral artery aneurysm was evaluated retrospectively. Six patients were examined with a spinal CT (HITACHI CT-W 3000) after intravenous bolus injection of 100ml contrast material (Iohexhol 300mgI/ml) at the rate of 2ml/s with a 25 second pre-scanning delay. The images of 3D-CTA were reconstructed using a new do-volume-render (Voxel Transmission) technique. The ages of the six patients ranged from 33 to 61 years and five cases were males and one case was female. Only one patient had a saccular aneurysm and the other five had fusiform aneurysms. Two patients underwent emergency operations within 4 days, and the other four had delayed operations. The outcome was good recovery in five cases and severe diability in one case. Postoperative conventional cerebral angiography demonstrated no delineation of the aneurysms in five cases. These results correspond well to postoperative BD-CTA. Postoperative conventional cerebral angiography could not be performed in only one patient, but the aneurysm was visualized on the third postoperative 3D-CTA. Proximal clipping is still one of the therapeuic options for ruptured vertebral aneurysms, but some reports emphasized the possibility of rebleeding after proximal clipping of vertebral artery aneurysms. The rebleeding occurred within 1 week after proximal clipping in 6 of 9 cases (66.7%), and the prognoses were extremely poor. Therefore, in patients selected for proximal clipping, it is necessary to undertake postoperative evaluation of the aneurysm within one week after proximal clipping. 3D-CTA is minimally invasive and can be easily performed repeatedly, even if the patients are in a poor condition. In conclusion, 3D-CTA is very useful especially for evaluation of ruptured vertebral artery aneurysms following proximal clipping.