Aims: Three-dimensional reconstruction of intracranial vessels is of interest for evaluation of aneurysms. This study determined diagnostic difference of three-dimensional digital subtraction angiography (3D-DSA, volume-rendering image) versus 2D-DSA for evaluating ruptured intracranial aneurysms, particularly focusing on the size of aneurysms as depicted in both images.
Settings and design: Sixty-nine patients underwent 3D-DSA and 2D-DSA. The relative size of an aneurysm, which is the ratio of the maximal diameter of an aneurysm to the diameter of a major vessel, was compared between imaging techniques. In addition, relative sizes of smaller aneurysms (< 5 mm) were compared with those of larger aneurysms (>10 mm).
Statistical analysis used: For comparison of aneurysm size and location of aneurysm, statistical analysis was performed with the Yates chi square test; statistical significance was set with a P value of less than 0.05.
Results: Sixty-three (73.3%) of the 86 total aneurysms were bigger when measured with 3D-DSA versus 2D-DSA. When measured with 3D-DSA, 28 (84.8%) of the 33 smaller aneurysms were bigger, and 50% of the larger aneurysms were bigger versus measurements of 2D-DSA images (P < 0.05). In ACA and ICA territories, which tended to have smaller mean aneurysmal size, relative size of the aneurysm was bigger when measured with 3D-DSA (81.5% and 81.0%, respectively). In MCA, where the mean aneurysmal size was the largest, relative size of aneurysms was bigger when measured with 3D-DSA in 15 cases (53.6%, P < 0.05). In the posterior circulation, aneurysm size was similar between 3D-DSA and 2D-DSA measurements.
Conclusions: 3D-DSA, especially volume-rendering images, tends to depict ruptured intracranial aneurysms bigger than 2D-DSA. This is particularly true with cerebral aneurysms that are < 5 mm in size and are located in the anterior circulation, especially ICA and ACA territories.