Background CZT-SPECT has good agreement in the evaluation of mechanical synchronization compared with conventional SPECT. The aim of this study was to evaluate the correlation between left ventricular mechanical contraction synchrony and left ventricular systolic function by gated myocardial perfusion imaging (GMPI) using cadmium–zine–telluride (CZT) single photon emission computed tomography (SPECT). Methods This retrospective study involved 371 patients (239 males and 132 females, mean age 61.06 ± 11.78 years old) who underwent GMPI at the Nuclear Medicine Department of Shanxi Cardiovascular Hospital from January 2020 to August 2020. Systolic synchrony parameters and left ventricular systolic function parameters were calculated via Emory Cardiac Toolbox, including PP, PSD, PHB, HS, HK, EDV, ESV, and LVEF. Based on LVEF value, patients were divided into the severe reduction group (group 1, 127 cases, EF < 35%), moderate reduction group (group 2, 47 cases, 35% ≤ EF < 45%), mild reduction group (group 3, 50 cases, 45% ≤ EF < 50%) and normal group (group 4, 147 cases, EF ≥ 50%). Differences in PP, PSD, PHB, HS and HK among the four groups were compared using one-way ANOVA. Differences between two groups were compared using LSD-t test. The correlation among functional and mechanical contraction synchrony factors were analyzed using Pearson test. Results PP, PSD, PHB, HS and HK were significantly different among the four groups (F = 5.20, 188.72, 202.88, 171.05, 101.36, P < 0.001). Pairwise comparison tests showed significant differences in PSD and PHB in each two groups, and HS and HK in each two groups except for group 2 and 3 (t = 0.28 and 0.39, both P > 0.001). PP was significantly higher in group 1, relative to group 3 (t = 2.43, P < 0.001) and group 4 (t = 3.67, P < 0.001). Pearson correlation analysis revealed that LVEF negatively correlates with PP, PSD, PHB (r = 0.194, − 0.790, − 0.799, all P < 0.001). HS and HK showed positive correlation for LVEF (r = 0.778 and 0.795, P < 0.001), PSD, PHB and ESV were had good positive correlation (r = 0.778, 0.795, P < 0.001), PSD, PHB and EDV had good positive correlation (r = 0.722, 0.732, P < 0.001). However, PP had poor correlation with EDV (r = 0.095, P > 0.001). HS and HK were negatively correlated with EDV and ESV (r =  − 0.700 to − 0.594, P < 0.001). Conclusion CZT SPECT GMPI provided left ventricular mechanical contraction synchrony parameters that correlated well with left ventricular systolic function. Worse left ventricular mechanical contraction synchrony lead to decreased LVEF, making the systolic synchrony parameters valuable in the prediction of left ventricular systolic function.

Objective: This study sought to compare the radiation dose and image quality between a snapshot assist (SSA) scanner and a conventional scanner in retrospective electrocardiographically (ECG)-gated coronary computed tomographic (CT) angiography to assess the clinical value of the SSA scanner in reducing radiation dose． Methods: Ninety-five patients with known or suspected coronary artery disease (CAD) undergoing retrospective ECG-gated Coronary CT Angiography were enrolled and divided into group A (n=47, with SSA scanner) and group B (n=48, with conventional scanner). The image quality scores, mean CT attenuation values in the ascending aorta, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed, and the radiation dose was compared between groups A and B. Results: There were no significant differences in patient sex, age, and mean body mass index (BMI) between the two groups. There were no significant differences in image quality scores for total segments between the two groups (χ2=0.147, P>0.05). The mean CT attenuation values in the ascending aorta were not significantly different between the two groups (t=1.120, P>0.05). There were no significant differences in SNR and CNR between the two groups (P>0.05). The effective dose (ED) of group A was 41.65% lower than group B (6.29±1.68 vs. 10.78±1.58mSv). Conclusion: SSA technology provides equivalent or better coronary image quality with retrospective ECG gated coronary angiography than the conventional scanner while enabling radiation dose reductions of 41.65%.

Osteoporosis (OP) is a metabolic bone disease which is characterized by loss of bone mineral content, decreased bone density, destruction of bone microstructure, and declined bone biomechanical evaluation index. In recent years, it was shown that bone marrow mesenchymal stem cells (MSCs) are involved in the form of exosomes, which has become a hot spot in the research of the pathogenesis of metabolic diseases. In this study, we intend to explore the effects of exosomes derived from MSCs on osteoblast apoptosis and OP. MSC-derived exosomes were obtained by ultracentrifugation and characterized by transmission electron microscopy (TEM). Exosomes were used to treat osteoblasts to observe cell apoptosis. The expression of apoptosis-related protein was detected by Western blot. Cell viability was examined by MTT assay. Cell apoptosis was assessed by TUNEL staining. TEM confirmed successfully extracted MSCs-derived exosomes. Exosomes intervention significantly reduced the expression of apoptosis-related pro-apoptotic proteins cytochrome c and caspase3, enhanced cell viability, and attenuated cell apoptosis in osteoblasts. MSCs-derived exosomes can inhibit osteoblasts apoptosis by suppressing apoptosis signaling pathways, thus improving osteoporosis, indicating that they might be used for the treatment of osteoporosis.