Modified Raymond-Roy Occlusion Classification

• Assessing Occlusion and Recovery in Large and Giant Intracranial Aneurysms: A Comparative Retrospective Study of Flow Diversion Alone Versus Combined With Coiling and the Role of Packing Density
• Interdependence of First-coil and Global volume embolization ratios (VERs) calculated by Sim&Size in predicting aneurysm occlusion outcomes
• Comparative analysis between stent-assisted coiling and Woven EndoBridge embolization for unruptured wide-necked bifurcation intracranial aneurysms: A propensity score matching study
• Comparison of Woven EndoBridge and stent-assisted coiling for treatment of acutely ruptured wide-neck bifurcation aneurysms: Single-center experience
• Retrospective multicenter analysis of the Trenza Embolization Device for endovascular therapy of intracranial aneurysms: initial results and short-term follow-up
• The ELVIS study: Medium and long-term Efficacy of LVIS EVO stent-assisted coil embolisation for unruptured saccular intracranial aneurysms-A tertiary single-centre experience
• Postoperative Time-of-Flight Magnetic Resonance Angiography Classification is a Predictor of Postoperative Recanalization of Unruptured Cerebral Aneurysms
• Use of the Neuroform Atlas Stent or LVIS Jr Stent for Treatment of Unruptured Intracranial Aneurysms in Parent Arteries of <2 mm in Diameter: A Multicenter Experience

Mascitelli et al. ¹⁾ in 2015 proposed a modified Raymond-Roy Occlusion Classification (MRRC) or modified Montreal scale, where class III is subdivided to reflect progression to occlusion:

class IIIa: contrast opacification within the coil interstices of a residual aneurysm

class IIIb: contrast opacification outside the coil interstices, along the residual aneurysm wall

The study from Mascitelli et al. found that class IIIa aneurysms progress to complete occlusion more than class IIIb aneurysms.

A validation study by Stapleton et al. confirmed that the predictive capability of the RROC was improved by the MRRC, showing not only that IIIa occluded more often (53.6% vs 19.2%) but that IIIb lesions would also further recanalize more frequently (65.1% vs 27.4%) ²⁾