What is the accuracy of CTA in determining the best treatment for aSAH?
In one series, 95.7% of patients with aSAH were referred for treatment on the basis of CTA. In 4.4% of patients, CTA did not provide enough information to determine the best treatment, and those patients required DSA; 61.4% of patients were referred to endovascular treatment on the basis of CTA; and successful coiling was achieved in 92.6%. The authors concluded that CTA with a 64-slice scanner is an accurate tool for detecting and characterizing aneurysms in acute aSAH and that CTA is useful in deciding whether to coil or clip an aneurysm.115 Partial volume averaging phenomena may artificially widen the aneurysmal neck and may lead to the erroneous conclusion that an aneurysm cannot be treated by endovascular coiling. This controversy is likely caused by the different technological specifications (16- versus 64-detector rows), slice thickness, and data processing algorithms of various CT systems, which have different spatial resolutions.