Low-Dose 3D Rotational Angiography in Measuring the Size of Intracranial Aneurysm: In Vitro Feasibility Study Using Aneurysm Phantom

Purpose: Three-dimensional (3D) measurement of intracranial aneurysms is important in planning endovascular treatment, and 3D rotational angiography (RA) is effective in accurate measurement. The purpose of this study was to evaluate the feasibility of low dose 3D RA (5 seconds 0.10 μGy/frame) in measuring an intracranial aneurysm using an in vitro phantom. Materials and Methods: We investigated an in vitro 3D phantom of an intracranial aneurysm with 10 acquisitions of 3D RA with a conventional dose (5 seconds 0.36 μGy/frame) and 10 acquisitions with a low-dose (5 seconds 0.10 μGy/frame). 3D size and neck diameters of the aneurysm were measured and compared between the 2 groups (conventional and low-dose) using noninferiority statistics. Results: The aneurysm measurements were well-correlated between the 2 readers, and non-inferiority in the measurement of aneurysmal size of low-dose 3D RA was demonstrated, as the upper margin of the 1-sided 97.5% confidence interval did not cross the pre-defined noninferi-ority margin of 0.2 mm by the 2 readers. Conclusion: Low-dose (5 seconds 0.10 μGy/frame) cerebral 3D RA is technically feasible and not inferior in in vitro 3D measurement of an intracranial aneurysm. Thus, low-dose 3D RA is promising and needs further evaluation for its clinical utility in the planning of endovascular treatment of an intracranial aneurysm.