In-Vivo Analysis; Bilateral Paired Injections

The DSA exposure protocols were compared by bilateral paired injections in 5 patients, respectively. Nine bilateral internal carotid artery and 8 bilateral vertebral artery pairs of normal angiograms were included. Radiation dose and image quality were compared between the ipsilateral and the contralateral anteroposterior (AP) and lateral views (protocol 1 vs. 4; and protocol 3 vs. 4) (Fig. 1). The projection angles, number of exposures, field of view, table height, source to distance, and tube angulations were matched for each paired injection. Injections were excluded from evaluation when selection of the target vessel failed or when there was marked asymmetricity of the vascular distribution. Protocol 2 was not implemented on any of the patients due to concerns of high-dose radiation exposure according to the in-vitro analysis.

Number of exposures, field of view, table height, source to distance, and tube angulations were matched for both injections. Despite lack of perceptible difference in image quality, about 40–50% of total AK and 25–40% of total DAP reduction was seen in patients studied with protocol 4. AK = air kerma, DAP = dose area product