Evaluation of 3D-CTA and flat detector DSA in diagnosing intracranial aneurysms: a comparative analysis

Objective: To evaluate three-dimension computed tomographic angiography (3D-CTA) and flat detector DSA in diagnosing intracranial aneurysms through a comparative analysis. Methods: A total of 44 consecutive spontaneous subarachnoid hemorrhage (SSAH) patients with suspected aneurysms underwent both 3D-CTA and flat detector DSA (including both 2D-DSA and 3D-DSA) examinations simultaneously. According to the diameter of intracranial aneurysms the patients were divided into two groups: < 3 mm group and ≥ 3 mm group. Results: A total of 46 aneurysms, which were confirmed by surgical operation or interventional therapy, were found in 36 patients. The sensitivity, specificity, positive predictive value and negative predictive value of 3D-CTA (2D-DSA, 3D-DSA-VR and 3D-DSA-MIP) in detecting intracranial aneurysms for all patients was 83.33% (77.8%, 100% and 94.44%), 75% (75%, 100% and 100%), 75% (73.68%, 100% and 100%) and 66.67% (75%, 100% and 100%), respectively. No significant difference in the diameter of aneurysm (Z=-0.178, P=0.859 >0.1) existed between 3D-CTA (VR) and 3D-DSA (VR) when Wilcoxon paired signed-rank test was used. Statistically significant difference in displaying the aneurysmal neck and its relation to the parent artery existed between 3D-CTA (VR) and 2D-DSA (P<0.05), and between 3D-CTA (VR) and 3D-DSA (VR) (P<0.05) as well, although no significant difference was found between 3D-CTA (VR) and 3D-DSA (MIP) (P>0.05). Conclusion: For the diagnosis of intracranial aneurysms with diameter ≥ 3 mm, 3D-CTA is quite effective and accurate. It can be used as a routine screening means. However, 3D-CTA carries high rate of missed diagnosis and misdiagnosis for intracranial aneurysms with the diameter < 3 mm. Therefore, 3D-DSA should be adopted in suspicious cases of SSAH in whom the intracranial aneurysms are not demonstrated on 3D-CTA. With the wide use of the flat detector DSA, 3D-DSA should be carried out after conventional DSA (2D-DSA) is performed in order to get more detailed 3D imaging, which is very helpful in guiding the treatment. (authors)