Brain aneurysms are more likely to rupture if they are growing even if they are small, a new study in Radiology reports. Aneurysms of 7 mm or more are the size where the benefits of treatment generally outweigh the risks of rupture, based on earlier studies. This had been interpreted that size alone is determinative of rupture risk. But ones that grow in size over time are at even greater risk for rupture, regardless of size. This means that all aneurysms of any size need to be followed. If they are growing, then treatment needs to be considered. Monitoring can be done by annual CT examination which is readily available and not cost prohibitive.