Changes of cerebral structure and perfusion in subtypes of systemic sclerosis: a brain magnetic resonance imaging study.

OBJECTIVES: The characteristics of brain impairment in different subtypes of systemic sclerosis (SSc) (dcSSc, diffuse cutaneous SSc; lcSSc, limited cutaneous SSc) remain unclear. This study aimed to characterize cerebral structure and perfusion changes in different subtype of SSc patients using magnetic resonance (MR) imaging. METHODS: Seventy SSc patients (46.0 ± 11.7 years, 62 females) and 30 healthy volunteers (44.8 ± 13.7 years, 24 females) were recruited and underwent brain MR imaging and Montreal Cognitive Assessment (MoCA) test. Gray matter (GM) volumes were measured using voxel-based morphometry analysis on T1-weighted images. Voxel-based and regional cerebral blood flow (CBF) was calculated on arterial spin labelling images. The cerebral structural and perfusion measurements by MR imaging were compared among dcSSc, lcSSc and healthy subjects using one-way ANOVA. The correlations between clinical characteristics and MR imaging measurements were also analyzed. RESULTS: The dcSSc patients exhibited a significant reduction in GM volume in the para-hippocampal region (cluster p < 0.01, FWE corrected) compared with healthy volunteers. Whereas, SSc patients, particularly lcSSc patients, showed elevated CBF in cerebellum, insula, cerebral cortex, and subcortical structures (regional analyses: all p < 0.05; voxel-based analyses: cluster p < 0.01, FWE corrected). Furthermore, clinical characteristics of modified Rodnan skin score (mRSS) (r value ranged from -0.29 to -0.45), MoCA scores (r = 0.40) and antinuclear antibody (ANA) positivity (r=-0.33) were significantly associated with CBF in some regions (all p < 0.05). CONCLUSION: The manifestations of brain involvement vary among different subtypes of SSc. In addition, severe skin sclerosis may indicate higher risk of brain involvement in SSc patients.

Improvement of Whole-body Bone Planar Images on a Bone-dedicated Single-photon Emission Computed Tomography Scanner by Blind Deconvolution Algorithm.

Purpose: We have developed a bone-dedicated collimator with higher sensitivity but slightly degraded resolution on single-photon emission computed tomography (SPECT) for planar bone scintigraphy, compared with conventional low-energy high-resolution collimator. In this work, we investigated the feasibility of using the blind deconvolution algorithm to improve the resolution of planar images on bone scintigraphy. Materials and Methods: Monte Carlo simulation was performed with the NCAT phantom for modeling bone scintigraphy on the clinical dual-head SPECT scanner (Imagine NET 632, Beijing Novel Medical Equipment Ltd.) equipped with the bone-dedicated collimator. Maximum likelihood estimation method was used for the blind deconvolution algorithm. The initial estimation of point spread function (PSF) and iteration number for the method were determined by comparing the deblurred images obtained from different input parameters. We simulated different tumors in five different locations and with five different diameters to evaluate the robustness of the initial inputs. Furthermore, we performed chest phantom studies on the clinical SPECT scanner. The quantified increased contrast ratio (CR) between the tumor and the background was evaluated. Results: The 2 mm PSF kernel and 10 iterations provided a practical and robust deblurred image on our system. Those two inputs can generate robust deblurred images in terms of the tumor location and size with an average increased CR of 21.6%. The phantom studies also demonstrated the ability of blind deconvolution, using those two inputs, with increased CRs of 17%, 17%, 22%, 20%, and 13% for lesions with diameters of 1 cm, 2 cm, 3 cm, 4 cm, and 5 cm, respectively. Conclusions: It is feasible to use the blind deconvolution algorithm to deblur the planar images for SPECT bone scintigraphy. The appropriate values of the PSF kernel and the iteration number for the blind deconvolution can be determined using simulation studies.

Characterization of kidneys in patients with systemic sclerosis by multi-parametric magnetic resonance quantitative imaging.

PURPOSE: To determine the usefulness of multiparametric magnetic resonance (MR) quantitative imaging in characterizing the kidneys in systemic sclerosis (SSc) patients. MATERIAL AND METHODS: Forty-six SSc patients (47.9 ± 12.8 years, 40 females) and 22 age- and sex- matched healthy volunteers (46.1 ± 13.8 years, 20 females) were recruited and underwent renal MR imaging by acquiring blood oxygen level dependent and saturated multi-delay renal arterial spin labeling (SAMURAI) sequences. The T2* value, T1 value, renal blood flow (RBF), arterial bolus arrival time (aBAT), and tissue bolus arrival time (tBAT) of renal cortex were measured and compared among diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc) groups and healthy controls using One-way ANOVA and analyzed by logistic regression. RESULTS: Compared to healthy volunteers, SSc patients with normal estimated glomerular filtration rate (n = 40) had significantly lower T2* value (P = 0.026) in the left renal cortex, longer T1 value (right: P = 0.015; left: P = 0.023), lower RBF (right: P < 0.001; left: P < 0.001), and shorter tBAT (right: P < 0.001; left: P = 0.005) in both right and left renal cortex after adjusting for demographics. The dcSSc patients (n = 23) had significantly lower RBF in both right (226.7 ± 65.2 mL/100 g/min vs. 278.2 ± 73.5 mL/100 g/min, P = 0.022) and left (194.5 ± 71.5 mL/100 g/min vs. 252.7 ± 84.4 mL/100 g/min, P = 0.020) renal cortex compared to the lcSSc patients (n = 23) after adjusting for demographics, but the significance of the difference was attenuated after further adjusting for modified Rodnan skin score and digital ulcers. CONCLUSION: Multi-parametric MR quantitative imaging, particularly multi-delay ASL perfusion imaging, is a useful technique for characterizing the kidneys and classification of SSc patients.

Selective internal radiation therapy with yttrium-90 resin microspheres followed by anatomical hepatectomy: A potential curative strategy in advanced hepatocellular carcinoma.

About 80% of hepatocellular carcinoma (HCC) patients are in advanced stages and ineligible for curative surgery. Palliative treatments just maintained limited survival, thus an effective downstaging therapy is badly needed. Here we report an initially unresectable patient who underwent radical hepatectomy after successful downstaging with selective internal radiation therapy (SIRT). A 34-year-old man was diagnosed with China Liver Cancer Staging (CNLC) IIIa HCC. Due to insufficient future liver remnant and vascular involvement, the patient was suggested to be unresectable. SIRT with yttrium-90 resin microspheres was given. At three months post-SIRT, a complete response was achieved. The tumor was downstaged to CNLC Ia stage. The patient underwent anatomical hepatectomy 5 months after SIRT. Histopathological examination of the resected specimen showed 4% viable tumor cells inside a necrotic mass. To our knowledge, this is the first case who underwent SIRT with yttrium-90 resin microspheres in China mainland. The success of the downstaging in this case renders a possible cure to be achieved in an initially unresectable patient. In addition, the nearly complete tumor necrosis in the resected specimen indicates a good prognosis post-surgery. This is the first case who underwent SIRT with yttrium-90 resin microspheres in China mainland. SIRT followed by anatomical hepatectomy is a potentially curative strategy for unresectable HCC, which deserves a confirmative trial in the future.

Diffusing capacity of lungs for carbon monoxide associated with subclinical myocardial impairment in systemic sclerosis: A cardiac MR study.

BACKGROUND: Systemic sclerosis (SSc) is characterised by microvascular and fibrotic lesions, which are located not only in skin but also in lungs and heart. OBJECTIVE: This study aimed to investigate the association between lung function and myocardial T1 values using cardiac MR (CMR) imaging in patients with SSc without cardiovascular symptoms. METHODS: The SSc patients and age- and sex-matched healthy subjects underwent CMR. The cardiac function and native T1 values of myocardium and lung function were measured. Spearman's rank correlations and linear regression analyses were performed to determine the association between lung function and myocardial T1. RESULTS: Forty-five SSc patients (aged 47.7±13.2 years, 40 females) and 23 (aged 46.0±14.4 years, 20 females) healthy subjects were enrolled. SSc patients exhibited considerably higher native T1 values compared with healthy subjects (1305.9±49.8 ms vs 1272.6±37.6 ms, p=0.006). Linear regression analysis revealed that decrease of diffusing capacity of lungs for carbon monoxide (DLCO) in SSc patients was notably associated with myocardial native T1 value before (ß -1.017; 95% CI -1.883 to -0.151; p=0.022) and after adjusting for confounding factors (ß -1.108; 95% CI -2.053 to -0.164; p=0.023). Moderate-to-severe decrease of DLCO was found to be significantly associated with myocardial native T1 value (ß 48.006; 95% CI 17.822 to 78.190; p=0.003) after adjusting for confounding factors. CONCLUSION: DLCO inversely correlates with myocardial native T1 values in SSc patients, particularly moderate-to-severely decreased DLCO, suggesting that DLCO might be a potential indicator for subclinical myocardial impairment in SSc patients.

Prognostic value of myocardial flow reserve measured with CZT cardiac-dedicated SPECT low-dose dynamic myocardial perfusion imaging in patients with INOCA.

BACKGROUND: Clinical use of dynamic myocardial perfusion imaging (D-MPI) of cadmium-zinc-telluride (CZT) cardiac-dedicated SPECT is growing, showing a higher application value than conventional SPECT. The prognostic value of ischemia in patients with non-obstructive coronary arteries (INOCA) remains an important challenge for investigation. The primary objective of this study was to investigate the prognostic value of myocardial flow reserve (MFR) measured with low-dose D-MPI of CZT cardiac-dedicated SPECT in the assessment of patients with INOCA. METHODS: Consecutive screening of patients with INOCA and obstructive coronary artery disease (OCAD) who had coronary angiography (CAG) data was performed within three months before or after D-MPI imaging. The patients who met the inclusion criteria were retrospectively analyzed and follow-up by telephone was performed. The enrolled patients were then divided into the INOCA and OCAD groups. INOCA was defined as signs and/or symptoms of myocardial ischemia but with < 50% epicardial stenosis. OCAD was defined as obstructive stenosis (≥ 50% stenosis) of epicardial coronary arteries or their major branches on the CAG. Medical treatments, Seattle Angina Questionnaire (SAQ) scores, and major adverse cardiac events (MACEs) were studied. The Kaplan-Meier survival curve, Log-rank test, and univariable COX regression analysis were used to evaluate the prognosis of patients and associated predictors, with P < 0.05 being considered statistically significant. RESULTS: A total of 303 patients (159 males and 144 females) were enrolled for the final analysis after excluding 24 patients who were lost to follow-up. The mean age of the included cases was 61.94 ± 8.59 years, of which 203 (67.0%) cases were OCAD and 100 (33.0%) cases were INOCA, respectively. The median follow-up was 16 months (14-21 months). Kaplan-Meier survival curves showed that the incidence of MACE was similar in the INOCA and OCAD groups (log-rank P = 0.2645), while those with reduced MFR showed a higher incidence of MACE than those with normal MFR (log-rank P = 0.0019). The subgroup analysis in the OCAD group revealed that 105 patients with reduced MFR had a higher incidence of MACE than those with normal MFR (log-rank P = 0.0226). The subgroup analysis in the INOCA group showed that 37 patients with reduced MFR had a higher incidence of MACE than those with normal MFR in the INOCA group (log-rank P = 0.0186). Univariable Cox regression analysis showed for every 1 unit increase in MFR, the risk of MACE for INOCA was reduced by 66.1% and that for OCAD by 64.2%. For each 1 mL·g-1·min-1 increase in LV-sMBF, the risk of MACE was reduced by 72.4% in INOCA patients and 63.6% in OCAD patients. CONCLUSIONS: MFR measured with low-dose D-MPI CZT SPECT provides incremental prognostic value in patients with INOCA. Patients with reduced MFR show an increased risk of MACE, increased symptom burdens, and impaired quality of life. INOCA patients with reduced MFR experienced higher rate of MACE than OCAD patients with normal MFR.

Characterization and Assessment of Projection Probability Density Function and Enhanced Sampling in Self-Collimation SPECT.

We have recently reported a self-collimation SPECT (SC-SPECT) design concept that constructs sensitive detectors in a multi-ring interspaced mosaic architecture to simultaneously improve system spatial resolution and sensitivity. In this work, through numerical and Monte-Carlo simulation studies, we investigate this new design concept by analyzing its projection probability density functions (PPDF) and the effects of enhanced sampling, i.e. having rotational and translational object movements during imaging. We first quantitatively characterize PPDFs by their widths and edge slopes. Then we compare the PPDFs of an SC-SPECT and a series of multiple-pinhole SPECT (MPH-SPECT) systems and assess the impact of PPDFs - combined with enhanced sampling - on image contrast recovery coefficient and variance through phantom studies. We show the PPDFs of SC- SPECT have steeper edges and a wider range of width, and these attributes enable SC-SPECT to achieve better performance.

Study of 99mTc absorption on micro-sized ion exchange resins to achieve high activity for SPECT.

In single-photon emission computed tomography (SPECT), a micro-sized 99mTc source is routinely used for performance measurement, geometry calibration, and system matrix generation. Therefore, a micro-sized source is critical in nuclear instrument production and quality control. Standard methods can only produce a point source with a large size and low total activity, as they are limited by the concentration of the 99mTc solution. The absorption of 99mTc on ion exchange resins has been used; however, few studies have quantitatively evaluated the absorption process and optimized the source activity. This paper proposes a procedure for producing a micro-sized 99mTc resin source with a super-high concentration, as well as a method for the fast measurement of the point source time-activity curve (TAC). Experiments on two resin point sources with diameters of 0.681 mm and 0.326 mm were carried out. Two semi-empirical models, including the first kinetic model and the pseudo-second-order rate equation model, were used to fit TACs. The results show the first kinetic model fit better, which suggests an acquisition time of 2-4 h is needed for optimization. The verification experiment demonstrates a resin point source with a diameter of 0.35 mm and total activity of 10.6 mCi (i.e., 59.1 Ci/mL concentration) was produced.

Sex-specific reference limits of left ventricular ejection fraction and volumes estimated by gated myocardial perfusion imaging for low-risk patients in China: a comparison between three quantitative algorithms.

BACKGROUND: Establishing appropriate reference value limits of left ventricular (LV) functional parameters is fundamental for the assessment of cardiac function. At present, there are no reports aimed at establishing reference limits using gated myocardial perfusion imaging (MPI) in mainland China. METHODS: A total of 175 consecutive patients who were defined as low-risk coronary artery disease patients underwent stress Technetium-99m sestamibi (99mTc-MIBI)-gated myocardial perfusion single-photon emission computed tomography (SPECT) imaging. The LV ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) were obtained by 3 quantitative algorithms: quantitative-gated SPECT, emory cardiac toolbox, and 4-dimensional model SPECT, respectively. The threshold values were obtained using Gaussian distribution or percentiles. The influence of gender, age, and weight on cardiac functional parameters was analyzed by multiple regressions for linear models. RESULTS: For males, the lower reference limits of EF were 52%, 63%, and 58%, respectively; and the upper limits of EDV/ESV were 106/45, 152/55, and 135/55 mL, respectively. For females, the lower reference limits of EF were 58%, 66%, and 65%, respectively; and the upper limits of EDV/ESV were 73/27, 105/31, and 88/29 mL, respectively. Compared to females, males had greater cardiac volume values and lower mean EF values. Bland-Altman plots revealed that the cardiac function parameters calculated by the three quantitative algorithms were in high agreement. CONCLUSIONS: In this study, the reference limits of cardiac parameters calculated by the 3 methods based on single-center data in China were preliminarily established. The threshold values determined by three quantitative algorithms were not interchangeable but were highly correlated.

Likely Common Role of Hypoxia in Driving 18F-FDG Uptake in Cancer, Myocardial Ischemia, Inflammation and Infection.

First introduced in 1976, 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) has become an indispensable tool for diagnosis and prognostic evaluation of tumors, heart disease, as well as other conditions, including inflammation and infection. Because 18F-FDG can accurately reflect the glucose metabolism level of organs and tissues, it is known as a "century molecule" and is currently the main agent for PET imaging. The degree of 18F-FDG uptake by cells is related to both the rate of glucose metabolism and glucose transporter expression. These, in turn, are strongly influenced by hypoxia, in which cells meet their energy needs through glycolysis, and 18F-FDG uptake increased due to hypoxia. 18F-FDG uptake is a complex process, and hypoxia may be one of the fundamental driving forces. The correct interpretation of 18F-FDG uptake in PET imaging can help clinics make treatment decisions more accurately and effectively. In this article, we review the application of 18F-FDG PET in tumors, myocardium, and inflammation. We discuss the relationship between 18F-FDG uptake and hypoxia, the possible mechanism of 18F-FDG uptake caused by hypoxia, and the associated clinical implications.

18F-ASEM Imaging for Evaluating Atherosclerotic Plaques Linked to α7-Nicotinic Acetylcholine Receptor.

BACKGROUND: Atherosclerosis is a chronic vascular inflammatory procedure alongside with lipid efflux disorder and foam cell formation. α7-Nicotinic acetylcholine receptor (α7nAChR) is a gated-calcium transmembrane channel widely expressed in neuron and non-neuron cells, such as monocytes and macrophages, activated T cells, dendritic cells, and mast cells. 18F-ASEM is an inhibitor targeted to α7nAChR that had been successfully applied in nervous system diseases. Previous studies had highlighted that α7nAChR was related to the emergency of vulnerable atherosclerotic plaques with excess inflammation cells. Thus, 18F-ASEM could be a complementary diagnostic approach to atherosclerotic plaques. MATERIALS AND METHODS: The synthesis of ASEM precursor and 18F-labeling had been performed successfully. We had established the ApoE-/- mice atherosclerotic plaques model (fed with western diet) and New Zealand rabbits atherosclerotic models (balloon-sprained experiment and western diet). After damage of endothelial cells and primary plaque formation, 18F-ASEM imaging of atherosclerotic plaques linked to α7nAChR had been conducted. In vivo micro-PET/CT imaging of ApoE-/- mice and the control group was performed 1 h after injection of 18F-ASEM (100-150 µCi); PET/CT imaging for rabbits with atherosclerotic plaques and control ones was also performed. Meanwhile, we also conducted CT scan on the abdominal aorta of these rabbits. After that, the animals were sacrificed, and the carotid and abdominal aorta were separately taken out for circular sections. The paraffin-embedded specimens were sectioned with 5 µm thickness and stained with hematoxylin-eosin (H&E) and oil red. RESULTS: In vivo vessel binding of 18F-ASEM and α7nAChR expression in the model group with atherosclerosis plaques was significantly higher than that in the control group. PET/CT imaging successfully identified the atherosclerotic plaques in ApoE-/- mice and model rabbits, whereas no obvious signals were detected in normal mice or rabbits. Compared with 18F-FDG, 18F-ASEM had more significant effect on the early monitoring of inflammation in carotid atherosclerotic plaques of ApoE-/- mice and model rabbits. 18F-ASEM had relatively more palpable effect on the imaging of abdominal aorta with atherosclerosis in rabbits. H&E and oil red staining identified the formation of atherosclerotic plaques in model animals, which provided pathological basis for the evaluation of imaging effects. CONCLUSION: We first confirmed 18F-ASEM as radiotracer with good imaging properties for precise identification of atherosclerotic diseases.

Self-Collimating SPECT With Multi-Layer Interspaced Mosaic Detectors.

Conventional single photon emission computed tomography (SPECT) relies on mechanical collimation whose resolution and sensitivity are interdependent, the best performance a SPECT system can attain is only a compromise of these two equally desired properties. To simultaneously achieve high resolution and sensitivity, we propose to use sensitive detectors constructed in a multi-layer in ter spaced mosaicdetectors (MATRICES) architecture to accomplish part of the collimation needed. We name this new approach self-collimation. We evaluate three self-collimating SPECT systems and report their imaging performance: 1) A simulated human brain SPECT achieves 3.88% sensitivity, it clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively; 2) a simulated mouse SPECT achieves 1.25% sensitivity, it clearly resolves 50- [Formula: see text] and 100- [Formula: see text] hot-rod patterns at noise-free and realistic count-levels, respectively; 3) a SPECT prototype achieves 0.14% sensitivity and clearly separates 0.3-mm-diameter point sources of which the center-to-center neighbor distance is also 0.3 mm. Simulated contrast phantom studies show excellent resolution and signal-to-noise performance. The unprecedented system performance demonstrated by these 3 SPECT scanners is a clear manifestation of the superiority of the self-collimating approach over conventional mechanical collimation. It represents a potential paradigm shift in SPECT technology development.

Rescue Protocol to Improve the Image Quality of 18F-FDG PET/CT Myocardial Metabolic Imaging.

PURPOSE: 18F-FDG PET myocardial metabolic imaging is used to estimate myocardial viability. However, poor image quality can affect the accurate quantification of viable myocardium. We assessed the feasibility of a rescue protocol that reinjected low-dose 18F-FDG with simultaneous 1 to 2 U of insulin injection and oral administration of 10 g of glucose to improve the image quality of 18F-FDG PET myocardial metabolic imaging. PATIENTS AND METHODS: Fifty-one consecutive patients with poor quality to uninterpretable 18F-FDG PET/CT myocardial metabolic images received the rescue protocol immediately after the initial image acquisition. The postrescue image acquisition was performed 1 hour later. The rescue image quality was compared with the initial image. The qualitative visual estimation of the images was graded as follows: grade 0, homogeneous, minimal uptake; grade 1, predominantly minimal or mild uptake; grade 2, moderate uptake; and grade 3, good uptake. The myocardium-to-blood pool activity ratio (M/B) was measured to assess the image quality quantitatively. RESULTS: The grades of 0 to 3 were observed in 24 (47%), 27 (53%), 0 (0%), and 0 (0%) patients, respectively, for the initial imaging, and in 0 (0%), 3 (5.9%), 4 (7.8%), and 44 (86.3%) patients for the rescue imaging (P < 0.001). The rescue M/B was significantly higher than the initial M/B (3.4 ± 1.4 vs 1.6 ± 0.6, respectively; P < 0.001). CONCLUSIONS: The rescue protocol successfully and rapidly improved the quality of myocardial 18F-FDG metabolic imaging.

The Availability of the α7-Nicotinic Acetylcholine Receptor in Early Identification of Vulnerable Atherosclerotic Plaques: A Study Using a Novel 18F-Label Radioligand PET.

Background: It has been confirmed that the α7-nicotinic acetylcholine receptor (α7nAChR) is an important target for identifying vulnerable atherosclerotic plaques. Previously, we successfully designed and synthesized a series of 18F-labeled PET molecular probes targeting α7nAChR, which are mainly used in the diagnosis of Alzheimer's disease. Based on the characteristics of α7nAChR in blood vessels, we have firstly screened for a suitable novel 18F-labeled PET molecular probe ([18F]YLF-DW), with high selectivity for α7nAChR over α4ß2nAChR and a good effect for the imaging of atherosclerotic animal models, to effectively identify vulnerable atherosclerotic plaques at an early stage. Meanwhile, we compared it with the "gold standard" pathological examination of atherosclerosis, to verify the reliability of [18F]YLF-DW in early diagnosis of atherosclerosis. Methods: The vulnerable atherosclerotic plaques model of ApoE-/-mice were successfully established. Then based on the methods of 3D-QSAR and molecular docking, we designed oxazolo[4,5-b] pyridines and fluorenone compounds, which are targeted at α7nAChR. Through further screening, a novel alpha7 nicotinic acetylcholine receptor radioligand ([18F]YLF-DW) was synthesized and automatically 18F-labeled using a Stynthra RNplus module. Subsequently, we employed [18F]YLF-DW for the targeting of α7nAChR in atherosclerotic plaques and control group, using a micro-PET/CT respectively. After imaging, the mice were sacrificed by air embolism and the carotid arteries taken out for making circular sections. The paraffin embedded specimens were sectioned with 5 µm thickness and stained with oil red. After staining, immunohistochemistry experiment was carried out to verify the effect of micro-PET/CT imaging. Results: The micro-PET/CT imaging successfully identified the vulnerable atherosclerotic plaques in the carotid arteries of ApoE-/-mice; whereas, no signal was observed in normal control mice. In addition, compared with the traditional imaging agent [18F]FDG, [18F]YLF-DW had a significant effect on the early plaques imaging of carotid atherosclerosis. The results of oil red staining and immunohistochemistry also showed early formations of carotid plaques in ApoE-/-mice and provided pathological bases for the evaluation of imaging effect. Conclusion: We innovated to apply the novel molecular probe ([18F]YLF-DW) to the identification of vulnerable atherosclerotic plaques in carotid arteries, to detect atherosclerosis early inflammatory response and provide powerful input for the early diagnosis of atherosclerotic lesions, which may play an early warning role in cardiovascular acute events.

Evaluation of left ventricular volumes and ejection fraction by 99mTc-MIBI gated SPECT and 18F-FDG gated PET in patients with prior myocardial infarction.

BACKGROUND: This study aimed to compare the accuracy of gated-SPECT (GSPECT) and gated-PET (GPET) in the assessment of left ventricular (LV) end-diastolic volumes (EDVs), end-systolic volumes (ESVs) and LV ejection fractions (LVEFs) among patients with prior myocardial infarction (MI). METHODS: One hundred and sixty-eight consecutive patients with MI who underwent GSPECT and GPET were included. Of them, 76 patients underwent CMR in addition to the two imaging modalities. The measurements of LV volumes and LVEF were performed using Quantitative Gated SPECT (QGS), Emory Cardiac Toolbox (ECTB), and 4D-MSPECT (4DM). RESULTS: The correlation between GPET, GSPECT, and CMR were excellent for LV EDV (r = 0.855 to 0.914), ESV (r = 0.852 to 0.949), and LVEF (r = 0.618 to 0.820), as calculated from QGS, ECTB, and 4DM. In addition, subgroup analysis revealed that EDV, ESV, and LVEF measured by GPET were accurate in patients with different extents of total perfusion defect (TPD), viable myocardium, and perfusion/metabolic mismatch. Furthermore, multivariate regression analysis identified that mismatch score was associated with the difference in EDV (P < 0.05) measurements between GPET and CMR. CONCLUSIONS: In patients with MI, LV volumes and LVEF scores measured by both GSPECT and GPET imaging were comparable to those determined by CMR, but should not be interchangeable in individual patients.

Preserved myocardial viability in patients with chronic total occlusion of a single coronary artery.

OBJECTIVE: To assess the benefits of coronary collateral circulation on myocardial perfusion, viability and function in patients with total occlusion of a single coronary artery using the 99mTc-sestamibi SPECT and 18F-fluorodeoxyglucose PET. METHODS: 164 Consecutive patients were included who underwent coronary angiography results exhibited total occlusion of a single coronary artery and received 99mTc-MIBI SPECT and 18F-FDG PET within 90 days of angiography. Myocardial perfusion and viability in patients with collateral circulation and those without it were compared. Long-term follow-up was performed through a review of patient clinical records. RESULTS: Collateral circulation was present in 56 patients (34%) and absent in 108 patients (66%). The total perfusion defect size in patients with collateral circulation decreased when compared to those without (30% ± 13% to 35% ± 14%, P < .05). The myocardial viability was 22% ± 12% in patients with collateral circulation, and 12% ± 9% in those without (P < .001). The left ventricular ejection fraction was higher, and the end-diastolic and end-systolic left ventricular volumes were lower in patients with collateral circulation (39% ± 11%, 138 ± 66, 89 ± 57) compared to patients without collateral circulation (31% ± 9%, 177 ± 55, 125 ± 48, all P < .001, respectively). Multi-factor logistic regression identified that concerning the variables of sex, age, viable myocardium, collateral circulation, treatment type and others, only treatment type was significantly associated with therapeutic effects (OR 3.872, 95% CI 1.915-7.830, P < .001). CONCLUSION: Collateral circulation can preserve resting myocardial blood perfusion and myocardial viability, and help maintain the function of the left ventricular myocardium. The appropriate treatment strategy will have a substantial impact on the therapeutic outcome.

Correction to: IGF-1C domain-modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI.

An amendment to this paper has been published and can be accessed via the original article.

IGF-1C domain-modified hydrogel enhanced the efficacy of stem cells in the treatment of AMI.

BACKGROUND: Due to the low survival rate of cell transplantation, stem cell has not been widely used in clinical treatment of acute myocardial infarction (AMI). In this study, we immobilized the C domain peptide of insulin-like growth factor-1 on chitosan (CS-IGF-1C) to obtain bioactive hydrogel. The purpose was to investigate whether CS-IGF-1C hydrogel incorporated with human placenta-derived mesenchymal stem cells (hP-MSCs) can boost the survival of hP-MSCs and enhance their therapeutic effects. METHODS: hP-MSCs, which continuously expressed green fluorescent protein (GFP) and firefly luciferase (Fluc), were transplanted with CS-IGF-1C hydrogel into a mouse myocardial infarction model. Cell survival was detected by bioluminescence imaging (BLI), and cardiac function was measured by echocardiogram. Real-time PCR and histological analysis were used to explore the therapeutic mechanism of CS-IGF-1C hydrogel. RESULTS: CS-IGF-1C hydrogel could induce the proliferation of hP-MSCs and exert anti-apoptotic effects in vitro. The Calcine-AM/PI staining results showed that hP-MSCs seeded on CS-IGF-1C hydrogel could protect neonatal mouse ventricular cardiomyocytes (NMVCs) against oxidative stress. It was observed by BLI that CS-IGF-1C hydrogel injected into ischemic myocardium could improve the survival rate of hP-MSCs. Histology analysis indicated that co-transplantation of the CS-IGF-1C hydrogel and hP-MSCs could increase angiogenesis, reduce collagen deposition, ameliorate left ventricular expanded, and further promote the recovery of cardiac function. Besides, we found that the inflammatory response was inhibited and the expression of apoptosis-related genes was downregulated by CS-IGF-1C hydrogel. CONCLUSIONS: CS-IGF-1C hydrogel provides a conducive microenvironment for cells and significantly boosts the survival of hP-MSCs in mouse myocardial infarction model, which suggest that it may be a potential candidate for prolonging the therapeutic effect of hP-MSCs during AMI.