Importance of imaging-acquisition protocol and post-processing analysis for extracellular volume fraction assessment by computed tomography

Hideki Koike; Victor Y Cheng; Andrew Lesser; Maurice Enriquez-Sarano; David J Caye; John Sukumar Aluru; Larissa I Stanberry; Erik B Schelbert; Hirotomo Sato; Miho Fukui; Vinayak N Bapat; Paul Sorajja; John R Lesser; João L Cavalcante

doi:10.1016/j.jcct.2023.02.007

Importance of imaging-acquisition protocol and post-processing analysis for extracellular volume fraction assessment by computed tomography

J Cardiovasc Comput Tomogr. 2023 May-Jun;17(3):222-225. doi: 10.1016/j.jcct.2023.02.007. Epub 2023 Mar 13.

Affiliations

¹ Cardiovascular Imaging Research Center and Core Lab at Minneapolis Heart Institute Foundation, Minneapolis, MN, USA.
² Allina Health Minneapolis Heart Institute at Abbott Northwestern Hospital, Minneapolis, MN, USA.
³ Allina Health Minneapolis Heart Institute at Abbott Northwestern Hospital, Minneapolis, MN, USA; Valve Science Center, Minneapolis Heart Institute Foundation, Minneapolis, MN, USA.
⁴ Valve Science Center, Minneapolis Heart Institute Foundation, Minneapolis, MN, USA.
⁵ Cardiovascular Imaging Research Center and Core Lab at Minneapolis Heart Institute Foundation, Minneapolis, MN, USA; Allina Health Minneapolis Heart Institute at Abbott Northwestern Hospital, Minneapolis, MN, USA; Valve Science Center, Minneapolis Heart Institute Foundation, Minneapolis, MN, USA. Electronic address: Joao.Cavalcante@allina.com.

PMID: 36922309
DOI: 10.1016/j.jcct.2023.02.007

Abstract

Background: Computed tomography angiography (CTA) assessment of myocardial extracellular volume fraction (CT-ECV) is feasible, although the protocols for imaging acquisition and post-processing methodology have varied. We aimed to identify a pragmatic protocol for CT-ECV assessment encompassing both imaging acquisition and post-processing methodologies to facilitate its clinical implementation.

Methods: We evaluated consecutive patients with severe aortic stenosis undergoing evaluation for transcatheter aortic valve replacement (TAVR). Pre-contrast and 3-min-delayed CTA were obtained in systole using either helical prospective-ECG-triggered (high-pitch) or axial sequential-ECG-gated acquisition, adding to standard TAVR CTA protocol. Using a dedicated software for co-registration of CTA datasets, three methodologies for ECV measurement were evaluated: (1) mid-septum region of interest (Septal ECV), (2) averaged-global ECV (Global ECV) encompassing 16-AHA segments, and (3) average of septal and lateral segments (Averaged ECVsep and Averaged ECVlat).

Results: Among the 142 patients enrolled (median = 81 years, 44% females), 8 were excluded due to significant imaging artifacts precluding Global ECV assessment. High-pitch scan mode was performed in 68 patients (48%). Suboptimal image quality for Global ECV assessment was associated with high-pitch scan mode (odds ratio: OR = 2.26, p = 0.036), along with the presence of intracardiac leads (OR = 4.91, p = 0.002), and BMI≥35 kg/m² (OR = 2.80, p = 0.026). Septal ECV [median = 29.4%] and Averaged ECVsep [29.0%] were similar (p = 0.108), while Averaged ECVlat [27.5%] was lower than Averaged ECVsep (p < 0.001), resulting in lower Global ECV [28.6%].

Conclusions: Myocardial CT-ECV assessment is feasible using a systolic sequential acquisition pre-contrast, and similar additional 3-min delayed scan. Septal ECV measurement provides similar values to Global ECV and is equally reproducible.

Keywords: And intracardiac device; Aortic stenosis; High-pitch scan acquisition; Sequential prospective-gated scan acquisition; Transcatheter aortic valve replacement.

MeSH terms

Aortic Valve Stenosis* / diagnostic imaging
Aortic Valve Stenosis* / surgery
Computed Tomography Angiography / methods
Female
Humans
Male
Predictive Value of Tests
Prospective Studies
Tomography, X-Ray Computed
Transcatheter Aortic Valve Replacement* / adverse effects
Transcatheter Aortic Valve Replacement* / methods