X Wu*, S Setlur Nagesh, E Vanderbilt, A Shields, C Ionita, D Bednarek, S Rudin, SUNY Buffalo, Buffalo, NY

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  X Wu

TH-C-201-1 (Thursday, 7/14/2022) 10:00 AM - 11:00 AM [Eastern Time (GMT-4)]

Room 201

Purpose: To acquire high-speed x-ray image sequences of contrast injections under pulsatile blood-flow conditions using simulated cardiac gating

Methods: A 60% water, 40% glycerol flow loop was attached to a patient-specific 3D-printed carotid-aneurysm phantom along with a programmable flow pump. The pump was configured to a 840 ms cardiac cycle, with 252 ms systole and 568 ms diastole, and an average and maximum flow rates of 8.7 and 25 mL/sec, respectively. The pump generates a TTL signal at a preprogrammed time-point on the cardiac waveform for synchronization purposes. Cardiac gating was simulated by performing a logical AND operation on the TTL signal and the x-ray “on” signal. The 100 um pixel-pitch Aries (Varex) photon-counting detector was used to acquire 2000 frame sequence of 1ms images. After detector initialization, iohexol contrast was injected into the flow loop using a programmable syringe injector at a constant rate of 20 ml/min. The 2000 ms image acquisition was started at the next cardiac gated time-point. The injection and acquisition was repeated 3 times. Time-Intensity curves (TIC) of contrast injection versus time were derived from the image sequences to confirm reproducible curves for the same time stamps. The Optical Flow method was then used to determine quantitative velocity information in different portions of the vessel and at different time-points.

Results: Similar TIC’s for three trials indicate reproducible synchronized image sequences for both systolic and diastolic time points. Optical Flow calculations verify that velocity distributions are also higher during systole than diastole, with an average aneurysm sac systolic velocity of around 22 cm/s compared to a diastolic velocity of 16 cm/s.

Conclusion: The simulated cardiac gating technique provides an accurate reference point to perform reproducible synchronized HSA image sequences of contrast injections under pulsatile blood flow conditions.

Keywords

DSA, Phantoms, Blood Flow

Taxonomy

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

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