Photon-Counting Detector CT Angiogram More Accurately Characterizes Lower Extremity Runoff than Traditional CT Angiogram

In this single-center, retrospective cohort study, we compared lower extremity Photon-counting detector CT (PCD-CT, n = 43) and conventional energy-integrating detector CT angiograms (EID-CTA, n = 46) to traditional on-table angiograms (angio) to assess whether there was a difference in the ability to characterize the target tibial vessel (TA) for potential lower extremity bypass between imaging modalities.In PCD-CTA vs angio, a different TA was identified in 2 patients (4.6%) whereas in EID-CTA vs angio, a different TA was identified in 10 patients (21.7%), p=0.03.PCD-CTA may allow for more accurate identification of the TA for lower extremity bypass than EID-CTA. Background:Evaluation of the infra-popliteal arteries can be challenging using traditional energyintegrating detector CT (EID-CTA) angiogram in patients with peripheral arterial disease (PAD).This is due to the small size and calcification of the tibial vessels, which creates significant calcium blooming artifact on EID-CTA making it challenging to distinguish calcium and contrast.Additionally, it is difficult to obtain strong contrast opacification of tibial vessels on EID-CTA due to the presence of occlusive disease, the high Hounsfield units of calcium resulting in saturated pixels, and venous contamination in patients with PAD or critical limb threatening ischemia (CLTI). 1 For these reasons, EID-CTA often cannot provide sufficient evaluation of the tibial vessels for lower extremity bypass planning, and on-table angiogram remains the gold standard.Photon-Counting Detector CTA (PCD-CTA) is an exciting new technology that has potential advantages over EID-CTA for evaluation of the infrapopliteal arteries. 2PCD-CTA J o u r n a l P r e -p r o o f This submission is not a clinical trial.It has not been registered in a public trials registry. This submission meets the criterial for a clinical trial, but it has not been registered in a public trials database.If you select this option, please provide a detailed explanation for why this study has not been registered in a public trials registry.