Feasibility and application of trimetazidine in 18F-FDG PET myocardial metabolic imaging of diabetic mellitus patients with severe coronary artery disease: A prospective, self-controlled study.

BACKGROUND: 18F-FDG PET myocardial metabolic imaging (MMI) is sometimes uninterpretable due to background activity from uncontrolled glucose homeostasis in diabetic mellitus (DM) patients. Trimetazidine is an oral medication that promotes the transformation of myocardial energy supply from free fatty acids to glucose. We aimed to investigate the feasibility and application of trimetazidine in 18F-FDG PET MMI of DM patients. METHODS: With DM patients exhibiting severe coronary artery disease (CAD) symptoms serving as self-controls, the effects of trimetazidine on PET MMI image quality, myocardial viability assessment, quantitative analytical parameters, and 18F-FDG uptake of different myocardial segments were elucidated. RESULTS: The image quality of 18F-FDG MMI was graded visually as good, moderate, and uninterpretable. After trimetazidine, grades of good, moderate, and uninterpretable were observed in 14 (60.9%), 8 (34.8%), and 1 (4.3%) patients, respectively, and in 4 (17.4%), 15 (65.2%), 4 (17.4%) patients without trimetazidine. The myocardial SUV and myocardial to blood pool SUV ratio (M/B ratio) were significantly higher after trimetazidine administration than those before (3.11 ± 1.07 vs 2.32 ± 1.00, 2.67 ± 1.41 vs 1.81 ± 0.75, P all < 0.01). 6 (3, 7) viable myocardium segments were detected with a mismatch score of 10 (6, 17) after trimetazidine, significantly higher than those before trimetazidine [5 (2, 7) and 8 (2, 17), P < 0.05]. Meanwhile, the 18F-FDG uptake in myocardial segments with decreased and normal perfusion showed different ranges of increase (by 15.30%-57.77%). CONCLUSION: Trimetazidine is feasible and effective in DM patients with severe CAD before 18F-FDG PET MMI, which can significantly improve the image quality and increase the number of viable myocardium segments detected. TRIAL REGISTRY: The study was registered in the Chinese Clinical Trial Registry (ChiCTR2000038559).

Global and regional cardiac dysfunction quantified by 18F-FDG PET scans can predict ventricular arrhythmia in patients with implantable cardioverter defibrillator.

BACKGROUND: A low appropriate therapy rate indicates that a minority of patients will benefit from their implantable cardioverter defibrillator (ICD). Quantitative measurements from 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) may predict ventricular arrhythmia (VA) occurrence after ICD placement. METHODS: We performed a prospective observational study and recruited patients who required ICD placement. Pre-procedure image scans were performed. Patients were followed up for VA occurrence. Associations between image results and VA were analyzed. RESULTS: In 51 patients (33 males, 53.9 ± 17.2 years) analyzed, 17 (33.3%) developed VA. Compared with patients without VA, patients with VA had significantly larger values in scar area (17.7 ± 12.4% vs. 7.0 ± 7.9%), phase standard deviation (51.4° ± 14.0° vs. 34.0° ± 15.0°), bandwidth (172.9° ± 39.8° vs. 128.7° ± 49.9°), sum thickening score (STS, 29.5 ± 11.1 vs. 17.8 ± 13.2), and sum motion score (42.9 ± 11.5 vs. 33.0 ± 19.0). Cox regression analysis and receiver operating characteristic curve analysis showed that scar size, dyssynchrony, and STS were associated with VA occurrence (HR, 4.956, 95% CI 1.70-14.46). CONCLUSION: Larger left ventricular scar burden, increased dyssynchrony, and higher STS quantified by 18F-FDG PET may indicate a higher VA incidence after ICD placement.

Evaluation of the diagnostic value of joint PET myocardial perfusion and metabolic imaging for vascular stenosis in patients with obstructive coronary artery disease.

BACKGROUND: To investigate the diagnostic value of joint PET myocardial perfusion and metabolic imaging for vascular stenosis in patients with suspected obstructive coronary artery disease (CAD). METHODS: Eighty-eight patients (53 and 35 applied for training and validation, respectively) with suspected obstructive CAD were referred to 13N-NH3 PET/CT myocardial perfusion imaging (MPI) and 18F-FDG PET/CT myocardial metabolic imaging (MMI) with available coronary angiography for analysis. One semi-quantitative indicator summed rest score (SRS) and five quantitative indicators, namely, perfusion defect extent (EXT), total perfusion deficit (TPD), myocardial blood flow (MBF), scar degree (SCR), and metabolism-perfusion mismatch (MIS), were extracted from the PET rest MPI and MMI scans. Different combinations of indicators and seven machine learning methods were used to construct diagnostic models. Diagnostic performance was evaluated using the sum of four metrics (noted as sumScore), namely, area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity. RESULTS: In univariate analysis, MIS outperformed other individual indicators in terms of sumScore (2.816-3.042 vs 2.138-2.908). In multivariate analysis, support vector machine (SVM) consisting of three indicators (MBF, SCR, and MIS) achieved the best performance (AUC 0.856, accuracy 0.810, sensitivity 0.838, specificity 0.757, and sumScore 3.261). This model consistently achieved significantly higher AUC compared with the SRS method for four specific subgroups (0.897, 0.839, 0.875, and 0.949 vs 0.775, 0.606, 0.713, and 0.744; P = 0.041, 0.005, 0.034 0.003, respectively). CONCLUSIONS: The joint evaluation of PET rest MPI and MMI could improve the diagnostic performance for obstructive CAD. The multivariate model (MBF, SCR, and MIS) combined with SVM outperformed other methods.

Exploring the Pathophysiology of Takotsubo Cardiomyopathy.

PURPOSE OF REVIEW: The purpose of this review is to explore the pathophysiology of Takotsubo cardiomyopathy by appraising the interplay between myocardial perfusion, function, metabolism, and, particularly, sympathetic innervation. RECENT FINDINGS: A number of hypotheses have been proposed to explain the pathogenesis of Takotsubo cardiomyopathy, which include (1) catecholamine cardiac toxicity, (2) myocardial sympathetic innervation disruption, (3) coronary vasospasm, (4) myocardial microvascular dysfunction, and (5) aborted myocardial infarction. These proposals are primarily derived from findings of nuclear myocardial perfusion, metabolism, and cardiac sympathetic innervation imaging. Although data in the literature are not necessarily uniform, the two most plausible working postulates for explaining the phenomenon are (1) regional myocardial stunning (due to coronary vasospasm, microvascular dysfunction, or aborted myocardial infarction) and (2) cardiac sympathetic innervation disruption or toxicity. Current data suggest that disturbances of both coronary circulation and neural innervation are associated with the Takotsubo cardiomyopathy: myocardial stunning from transient ischemic attack and sympathetic innervation disruption. It remains to be determined, however, whether the observed leading mechanistic explanations that have gained momentum are merely the sequelae of the disease rather than its primary etiology.

Relationship Between Septal Myocardial Metabolism and Left Ventricular Mechanical Synchronization in Patients With Dilated Cardiomyopathy and Left Bundle Branch Block / 中国循环杂志

Objective: To explore the relationship between septal myocardial metabolism and left ventricular mechanical synchronization in patients with dilated cardiomyopathy (DCM) and left bundle branch block (LBBB) by gated 18F-FDG myocardial metabolic imaging. Methods: A total of 20 consecutive patients diagnosed for DCM with LBBB from 2010-10 to 2013-05 were enrolled, there were 11 male and 9 female at the mean age of (54±11) years. All patients received gated 18F-FDG myocardial metabolic PET imaging. TrueD software was used to determine the maximal standardized 18F-FDG uptake value (S-SUVmax) and the average standardized uptake value (S-SUVavg). QGS software was applied to conduct left ventricular phase analysis and to detect the cardiac function, left ventricular bandwidth (BW), standard deviation of bandwidth (SD), left ventricular end-diastolic volume (LVEDV), LVESV and LVEF. The relationship between 18F-FDG uptake in septal myocardium with the indexes of phase analysis and the indexes of cardiac function was analyzed. Results: S-SUVmax and S-SUVavg were respectively negatively related to BW (r=-0.44, P0.05. Conclusion: In patients of DCM with LBBB, reduced septal myocardial metabolism was closely related to left ventricular mechanical synchronization, gated 18F-FDG myocardial metabolic PET imaging may simultaneously detect both functions, which was important for prognostic evaluation and therapeutic monitoring in clinical practice;phase analysis.

Main Technical Parameters and Clinical Application of Biograph 64 TruePoint PET/CT / 医疗卫生装备

The basic structure, primary parameters of PET/CT and the clinical application value on tumor system, cardio-vascular system and nerval system are simply introduced. The 64 slices PET/CT is significant in directing coronary heart disease diagnosis and treatment. The PET of the 18F-FDG cardiac muscle metabolism and coronary artery imaging can be operated by this equipment at the same time, which can confirm the activeness of the cardiac muscle and the blood-supply for the coronary arterial distributing. This has a determinative meaning for the choosing of Rx.