Computerized Occlusion Rating of Embolized Ruptured Intracranial Aneurysms: Relation to Intra- and Postinterventional Aneurysm Rehemorrhage

Abstract

Endovascular coil occlusion of ruptured cerebral aneurysms has a higher rate of rebleeding compared to surgical clipping. Initial aneurysm coil occlusion rate (OR) is the strongest available predictor of aneurysm rebleeding. Standard clinical subjective occlusion rating (SOR) is limited by subjective bias. Therefore, computerized occlusion rating (COR) was introduced. Its superiority was established for experimental and human aneurysms. In the present clinical study, we aimed to evaluate COR as a risk factor for postprocedural reruptures (PPRs) and intraprocedural reruptures (IPRs). In our series of 249 consecutive patients treated in our institution, we observed 7 (2.8%) cases with IPR and 7 (2.8%) cases with PPR. These patients were analyzed in the present study. Mean COR value was 85% (range 71-96%). In 12 (85.7%) cases, COR was lower than SOR. In aneurysms with a COR of 95% or higher, no PPR occurred. All patients with IPR harbored multiple aneurysms. In -conclusion, our data showed a distinct tendency of potentially dangerous overestimations when using SOR compared to the objectively measured COR values. IPR was always associated with multiple aneurysms.

An update to the Raymond–Roy Occlusion Classification of intracranial aneurysms treated with coil embolization

“…Certainly many occlusion grades are debatable, and it has been shown that there is frequently disagreement between observers when using these grading scales (especially as the number of categories in the scale increases) 28 29. Some authors have advocated replacing the RROC system with computerized grading scales due to the subjective nature of the classification and interobserver variation 30 31. In addition, the MRRC does not differentiate between contrast flow and stasis, which may also be an important factor 14 15 19…”