Background To evaluate anatomical and clinical factors that make trans-radial cerebral angiography more difficult.

Methods A total of 52 trans-radial diagnostic angiograms were evaluated in a tertiary care stroke center from December 2019 until March 2020. We analyzed a number of anatomical variables to evaluate for correlation to outcome measures of angiography difficulty.

Results The presence of a proximal radial loop had a higher conversion to femoral access (p<0.03). The presence of a large diameter aortic arch (p<0.01), double subclavian innominate curve (p<0.01), left proximal common carotid artery (CCA) loop (p<0.001), acute subclavian vertebral angle (p<0.01), and absence of bovine aortic arch anatomy (p=0.03) were associated with more difficult trans-radial cerebral angiography and increased fluoroscopy time-per-vessel.

Conclusion The presence of a proximal radial loop, large diameter aortic arch, double subclavian innominate curve, proximal left CCA loop, acute subclavian vertebral angle, and absence of bovine aortic arch anatomy were associated with more difficult trans-radial cerebral angiography. We also introduce a novel grading scale for diagnostic trans-radial angiography.