Optimal phase analysis of electrocardiogram-gated computed tomography angiography in patients with Stanford type A acute aortic dissection

Kenji Nishida; Yuki Yokoi; Ayumi Yamada; Nobuhiro Takaya; Ken Yamagiwa; Shuichi Kawada; Koichi Mori; Susumu Manabe; Eiichiro Kanda; Tomoyuki Fujioka; Mitsuhiro Kishino; Ukihide Tateishi

doi:10.1016/j.ejro.2020.100289

Optimal phase analysis of electrocardiogram-gated computed tomography angiography in patients with Stanford type A acute aortic dissection

Eur J Radiol Open. 2020 Dec 9:7:100289. doi: 10.1016/j.ejro.2020.100289. eCollection 2020.

Authors

Affiliations

¹ Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan.
² Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan.
³ Department of Cardiovascular Surgery, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan.
⁴ Department of Nephrology, Kawasaki Medical School Hospital, 577 Matsushima, Kurashiki, Okayama, Japan.

Abstract

Objective: To determine the phase that facilitates flap observation of the ascending aorta in Stanford type A acute aortic dissection with perfused false lumen.

Methods: We reconstructed retrospective Electrocardiogram-gated Computed Tomography Angiography images of the ascending aorta of all 20 patients to 20 phases of curved-multiplanar reconstruction in 5% increment. One radiologist created and randomized 10 cross-sectional images of each phase for every patient and two radiologists scored these images on a 5-point scale depending on the degree of flap stoppage. We calculated the average score for each phase of each case and compared them among the three groups.

Results: Image scores were significantly better in the 65 %-100 % R-R interval group than those in the 5%-30 % (p < 2e-16) and 35 %-60 % R-R interval groups(p = 7.2e-10). Similar scores were observed in the Heart Rate > 70 group (p = 0.00039, 2.2e-14). Moreover a similar tendency was observed in the arrhythmia group (p = 0.0035, 0.294). No difference was found in the degree of flap stoppage in the 65 %-100 % R-R interval group between the Heart Rate > 70 and Heart Rate ≤ 70 groups (p = 0.466) and between the arrhythmia and non-arrhythmia groups (p = 0.1240).

Conclusion: In observing the ascending aorta, We obtained a good image at 65 %-100 % R-R interval and similar tendency was observed in the patients with arrhythmia.

Keywords: AAD, acute aortic dissection; AC, atrial contraction phase; AEC, automatic exposure control; AR, Aortic Regurgitation; Aorta thoracic; CTA, computed tomography angiography; Computed tomography angiography; D, diastolic phase; DLP, dose-length-product; Dissecting; E, effective dose; ECG, electrocardiogram; Electrocardiography; HR, heart rate; IVR, isovolumetric relaxation phase; MPR, multiplanar reconstruction; RF, rapid filling phase; RR, R-R interval; Radiation dose; S, systolic phase; SF, slow filling phase; bpm, beats per minute.