Arms Down Cone Beam CT Hepatic Angiography Performance Assessment: Vascular Imaging Quality and Imaging Artifacts

Introduction: The practice of positioning patients' arms above the head during catheter-injected hepatic arterial phase cone beam CT (A-CBCT) imaging has been inherited from standard CT imaging due to image quality concerns, but interrupts workflow and extends procedure time. We sought to assess A-CBCT image quality and artifacts with arms extended above the head versus down by the side.

Methods: We performed an IRB approved retrospective evaluation of reformatted and 3D-volume rendered images from 91 consecutive A-CBCTs (43 arms up, 48 arms down) acquired during hepatic tumor arterial embolization procedures. Two interventional radiologists reviewed all A-CBCT imaging and assigned vessel visualization scores (VVS) from 1 to 5, ranging from non-diagnostic to optimal visualization. Streak artifacts across axial images were rated from 1 to 3 based on resulting image quality (none to significant). Presence of respiratory or cardiac motion during acquisition, body mass index and radiation dose area product (DAP) were also recorded and analyzed. Univariate and multivariate analyses were used to assess the impact of arm position on VVS and imaging artifacts.

Results: VVS were not significantly associated with arm position during A-CBCT imaging. One reader reported more streak artifacts across axial images in the arms down group (p = 0.005). DAP was not statistically different between the groups (23.9 Gy cm² [6.1-73.4] arms up, 26.1 Gy cm² [4.2-102.6] arms down, p = 0.54).

Conclusion: A-CBCT angiography performed with the arms above the head is not superior for clinically relevant hepatic vascular visualization compared to imaging performed with the arms by the patient's side.