13 N-ammonia PET-derived right ventricular longitudinal strain and myocardial flow reserve in right coronary artery disease

Abstract

Purpose:We developed a feature-tracking algorithm for use with electrocardiography-gated high-resolution 13 N-ammonia positron emission tomography (PET) imaging, and we hypothesized it could be used to clarify the association between right ventricular (RV) longitudinal strain (LS) and right coronary artery (RCA) ischemia. The aim of this study was to investigate the association between the reduction of regional myocardial flow reserve (MFR) in RCA territories and PET-derived LS of the RV free wall. Methods: Ninety-three patients with coronary artery stenosis > 50%, diagnosed by coronary computed tomography angiography, and 10 controls were retrospectively analyzed. RV-LS in the free wall was measured by a feature-tracking technique on the resting and stressed 13 N-ammonia PET images of horizontal long-axis slices. The patients were sub-grouped according to regional MFR values at the territories of RCA, left anterior descending artery (LAD), and left circumflex coronary artery (LCx): RCA-MFR<2.0 [n=34], RCA-MFR 2.0 but MFR<2.0 at LAD or LCx territories [n=11], and for all territories [n=48]. Stress and resting RV-LS were compared in each of the four groups. Multiple comparisons of RV-LS among the four groups were performed in the stress and resting state.Results: Decreased stress RV-LS in patients with an RCA-MFR<2.0 was observed. In the patients with for all territories, the stressed RV-LS was significantly increased compared to that in the resting state. Significantly decreased RV free-wall LS during adenosine stress in patients with RCA-MFR<2.0 was observed in the other three groups. Conclusions:We measured RV myocardial LS using feature tracking in cine imaging of 13 N-ammonia PET.The results of this study suggest that PET-derived stressed RV-LS is useful for detecting reduced RV myocardial motion due to ischemia in the RCA territory.

Myocardial Strain Derived from ¹³N-ammonia Positron Emission Tomography

“…In terms of objectivity and reproducibility, it is considered to be no less than echocardiography. In addition, the right ventricular strain is calculated from this algorithm, challenging the evaluation of right ventricular function (10). One limitation of this algorithm is that in the broad infarcts, 13 N-ammonia accumulation becomes deficient and the contour disappears.…”