E Vanderbilt*, A Shields, X Wu, S Setlur Nagesh, D Bednarek, S Rudin, University at Buffalo (SUNY) School of Medicine, Buffalo, NY

• 
  E Vanderbilt

TH-A-207-3 (Thursday, 7/14/2022) 7:30 AM - 8:30 AM [Eastern Time (GMT-4)]

Room 207

Purpose: Clinical contrast injections for angiography typically utilize a large bolus to completely fill the vessel lumen to qualitatively assess patency and morphology. This technique is suboptimal for high-speed angiography (HSA), where specialized injections are needed for visualization of detailed flow streamlines. This study evaluates the effect of pulsatile flow and its influence on the spatial variation of the contrast injection in enhancing flow visualization throughout the high-speed acquisition.

Methods: To illustrate the benefit of pulsatile flow for HSA, a programmable flow pump was used to generate first constant and then alternatively pulsatile flow conditions in a range of patient-specific carotid aneurysm models. The average flow rate of the pulsatile-flow waveform was equivalent to the constant flow rate. Iodine contrast was automatically injected in each aneurysm model, and a high-speed photon-counting detector (Aries, Varex) was used to capture flow patterns at 1000 fps using an RQA5 spectrum. Within the pulsatile-flow waveform, several trigger points were selected and used to synchronize the Aries-detector acquisition. Quantitative flow analysis was performed at various 300-ms segments of the pulsatile-flow cycle using an Optical Flow method.

Results: Compared to constant flow, the injections during the pulsatile-flow cycle create stronger edges of contrast throughout the systolic and diastolic phases. During diastole, the contrast pools at the site of the catheter tip, and is then broken up during the systolic phase. This produces multiple wavefronts of contrast which better illustrate the changing fluid dynamics within the inflow vessel and aneurysm sac. The Optical-Flow-derived velocity distributions reflect the change in pulsatile phase.

Conclusion: Pulsatile flow introduces additional spatial gradients in the contrast distribution, which are useful for detailed flow visualization and quantitative analysis. Synchronization of the detector and flow waveform allows for targeted evaluation of systolic and diastolic intervals, which enhances quantification of in-vivo flow conditions.

Funding Support, Disclosures, and Conflict of Interest: This research was supported by NIH Grant R01EB030092, and in part by Canon Medical Systems Inc.

Keywords

Blood Flow, Contrast Agent, DSA

Taxonomy

IM- X-Ray: Fluoroscopy, digital angiography, and DSA

Contact Email