Diagnostic quality and accuracy of low dose 3D-DSA protocols in the evaluation of intracranial aneurysms

Background: 3D-DSA is the 'gold standard' imaging technique for the diagnosis and characterization of intracranial aneurysms. Objective: To compare the image quality and accuracy of low dose 3D-DSA protocols in patients with unruptured intracranial aneurysms. Materials and methods: The standard manufacturer 5 s 0.36 μGy/f protocol and one of three low dose 3DDSA protocols (5 s 0.10 μGy/f, 5 s 0.17 μGy/f, 5 s 0.24 μGy/f) were performed in 12 patients with unruptured intracranial aneurysms. Three interventional neuroradiologists, two neurosurgeons, and two neurologists rated the image quality of all 3D reconstructions as good, acceptable, or poor. Three interventional neuroradiologists measured two dimensions of each aneurysm for all protocols. The radiation dose metric Ka,r (reference point air kerma, in mGy) was recorded for each 3D-DSA protocol. Results: The standard 5 s 0.36 μGy/f protocol earned the highest average subjective rating of 2.76, followed by the 5 s 0.24 μGy/f (2.72), and 5 s 0.17 μGy/f (2.59) protocols. The ranges of differences in aneurysm measurements between the 5 s 0.24 μ Gy/f protocol and the standard were <0.5 mm. The median Ka,r metrics for each protocol were as follows: 5 s 0.36 μGy/f (89.0 mGy), 5 s 0.24 μGy/f (57.7 mGy), 5 s 0.17 μGy/f (45.9 mGy), and 5 s 0.10 μGy/f (27.6 mGy). Conclusions: Low dose 3D-DSA protocols with preserved image quality are achievable, and can help reduce exposure of patients and operators to unnecessary radiation. The 5 s 0.24 μGy/f protocol generates one-third smaller radiation dose than the standard 5 s 0.36 μGy/f protocol without compromising diagnostic image quality or accuracy.