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. 2024 Sep:178:111604.
doi: 10.1016/j.ejrad.2024.111604. Epub 2024 Jul 6.

Prospective ECG-gated High-Pitch Photon-Counting CT Angiography: Evaluation of measurement accuracy for aortic annulus sizing in TAVR planning

Y Yang  1 , R Richter  1 , M C Halfmann  1 , D Graafen  1 , M Hell  2 , M Vecsey-Nagy  3 , G Laux  2 , L Kavermann  2 , T Jorg  1 , M Geyer  2 , A Varga-Szemes  4 , T Emrich  5
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Free article

Prospective ECG-gated High-Pitch Photon-Counting CT Angiography: Evaluation of measurement accuracy for aortic annulus sizing in TAVR planning

Y Yang et al. Eur J Radiol. 2024 Sep.
Free article

Abstract

Purpose: In planning transcatheter aortic valve replacement (TAVR), retrospective cardiac spiral-CT is recommended to measure aortic annulus with subsequent CT-angiography (CTA) to evaluate access routes. Photon-counting detector (PCD)-CT enables to assess the aortic annulus in desired cardiac phases, using prospective ECG-gated high-pitch CTA. The aim of this study was to evaluate the measurement accuracy of aortic annulus using prospective ECG-gated high-pitch CTA against retrospective spiral-CT reference.

Method: Thirty patients underwent cardiac spiral-CT and prospective ECG-gated (30% R-R on aortic valve level) high-pitch CTA. Using propensity score matching, another 30 patients were identified whose CTA was performed using high-pitch mode without ECG-synchronization. Two investigators measured annular diameter, perimeter, and area on cardiac spiral-CT and high-pitch CTA.

Results: The aortic valve was imaged in systole in 90 % of prospective ECG-gated CTA cases but only 50 % of non-ECG-gated CTA cases (p = 0.002). There was a strong correlation (r ≥ 0.94) without significant differences (p ≥ 0.09) between cardiac spiral-CT and prospective ECG-gated high-pitch CTA for all annulus measurements. In contrast, significant differences were found in annular short-axis diameter and area between cardiac spiral-CT and non-ECG-gated high-pitch CTA (p ≤ 0.03). Furthermore, prospective ECG-gated high-pitch CTA showed significantly reduced radiation exposure compared with cardiac spiral-CT (CTDI 4.52 vs. 24.10 mGy; p < 0.001).

Conclusion: PCD-CT-based prospective ECG-gated high-pitch scans with targeted systolic acquisition at the level of the aortic valve can simultaneously visualize TAVR access routes and accurately measure systolic annulus size. This approach could aid in optimizing protocols to achieve lower radiation doses in the growing population of younger, low-risk TAVR patients.

Keywords: Aortic annulus measurement; Photon Counting CT; TAVR; prospective ECG-gated high-pitch CTA.

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Conflict of interest statement

Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: T. Emrich receives speaker fee, institutional research-/ travel support from Siemens Healthineers and is advisory board member from Siemens Healthineers and consultant from Circle Cardiovascular Imaging. Y. Yang, M. C. Halfmann, D. Graafen and T. Jorg receive institutional research support from Siemens Healthineers. A. Varga-Szemes receives institutional research support and/or personal fee from Bayer, Elucid and Siemens Healthineers.

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