Low septal to lateral wall 18F-FDG ratio is highly associated with mechanical dyssynchrony in non-ischemic CRT candidates

Abstract

BackgroundIn order to better understand the concept of mechanical dyssynchrony, a promising hallmark of cardiac resynchronization therapy (CRT) response, we investigated its effect on regional myocardial metabolism and myocardial blood flow (MBF) in non-ischemic CRT candidates.ResultsThirty consecutive non-ischemic CRT eligible patients underwent static 18F-FDG and resting dynamic 13N-NH3 PET/CT. 18F-FDG uptake and MBF for septal and lateral wall were analysed and septal-to-lateral wall ratios (SLR) were calculated. Based on the presence of mechanical dyssynchrony (septal flash and/or apical rocking) on echocardiography, patients were divided into 2 groups, with (n = 23) and without (n = 7) mechanical dyssynchrony.Patients with mechanical dyssynchrony had significantly lower 18F-FDG SUVmean in the septum compared with the lateral wall (5.58 ± 2.65 vs 11.19 ± 4.10, p < 0.0001), while patients without mechanical dyssynchrony had a more homogeneous 18F-FDG distribution (7.33 ± 2.88 vs 8.31 ± 2.50, respectively, p = 0.30). Similarly, MBF was significantly different between the septal and lateral wall in the dyssynchrony group (0.57 ± 0.11 ml/g/min vs 0.92 ± 0.23 ml/g/min, respectively, p < 0.0001), whereas no difference was observed in the non-dyssynchrony group (0.61 ± 0.23 ml/g/min vs 0.77 ± 0.21 ml/g/min, respectively, p = 0.16). 18F-FDG SLR, but not MBF SLR, was associated with the presence of mechanical dyssynchrony and showed a significant inverse correlation with volumetric reverse remodeling after CRT (r = − 0.62, p = 0.001).ConclusionsNon-ischemic heart failure patients with mechanical dyssynchrony demonstrate heterogeneous regional metabolism and MBF compared with patients without dyssynchrony. However, only 18F-FDG SLR appeared to be highly associated with the presence of mechanical dyssynchrony.Trial registrationClinicaltrials, NCT02537782. Registered 2 September 2015.

Deep Learning-Based Image Registration in Dynamic Myocardial Perfusion CT Imaging

“…We can observe small differences with a slightly decreased value of 61 ml/100g/min in the apical region and a slightly higher value in the lateral wall area of 72 ml/100g/min. These values and small deviations correspond well to standard mean blood flow (MBF) in the literature [40].…”

Can nuclear imaging accurately detect scar in ischemic cardiac resynchronization therapy candidates?

“…This concept of detecting viable or scarred tissue with PET might be challenging in patients with ventricular conduction abnormalities. In previous work, we have demonstrated a heterogeneous regional distribution of absolute myocardial perfusion and glucose metabolism in nonischemic CRT candidates [4,5]. In particular, a low 13 N-NH 3 -derived absolute myocardial blood flow (MBF) and 18 F-FDG uptake in the septum were observed with high values in the lateral wall, most likely representing a physiological adaptation of the heart to the alterations in myocardial workload and energy demands [6].…”