Raymond-Roy classification

The Raymond-Roy occlusion classification is the most widely used way to describe the angiographic result after endovascular coiling of an intracranial aneurysm. Class 1 is complete occlusion. Class 2 is a residual neck, where contrast fills a small portion at the base of the aneurysm. Class 3 is a residual aneurysm, where contrast enters the dome itself.

A modified version splits class 3 into 3a (contrast within the coil interstices) and 3b (contrast along the aneurysm wall), because the two behave differently over time: 3a lesions more often progress to occlusion, while 3b lesions more often recanalize.

Follow-up imaging is usually compared against the immediate post-treatment grade. A shift to a worse class, especially to class 3, is what most studies count as major recanalization and is the usual trigger for discussing retreatment.