3-Dimensional computed tomographic angiography for use of surgery planning in patients with intracranial aneurysms

Background. After subarachnoid haemorrhage (SAH) diagnostic evaluation of the underlying cause is warranted since the rebleeding rate is high. The objective of the study was to answer the question, whether 3-Dimensional computed tomographic angiography (3D-CTA) is able to accurately determine the surgical indications in patients with intracranial aneurysms. Methods. After performing 3D-CTA the size of the aneurysm, direction of the aneurysmal dome, neck position and variants of the circle of Willis were analysed. Surgery was performed solely on CTA data in those cases, where the aneurysm was clearly visible. If the findings were negative or inconclusive, intra-arterial digital subtraction angiography (DSA) was also done. Findings. Between January 2001 and December 2002 100 patients (68 F, 32M) were examined and 123 aneurysms (86 ruptured and 37 unruptured) were diagnosed. All patients received CTA preoperatively and in 27 patients selective DSA was additionally performed. Postoperatively in 34 patients the operative result was checked by DSA. A good correlation between CTA and the intra-operative findings was present in 92 of 100 patients. One aneurysm was not seen on CTA, but was on DSA. In four cases we could confirm DSA findings in CTA after re-evaluation of the data. In three cases neither CTA nor DSA clearly showed an aneurysm, but it was confirmed during surgery. A good correlation between CTA and DSA was found in 60 of 61 patients (98%). The correlation between CTA and intra-operative findings was good as expected in 92 patients, in 5 patients an aneurysm was detected on re-evaluation. Only one aneurysm could not be demonstrated by CTA but in DSA. Conclusion. CTA is less invasive, less time consuming, cheaper and easier to demonstrate the essential information regarding the aneurysm than DSA. We therefore recommend that following a careful analysis most aneurysms -92%-can be operated solely on CTA data.