Effects of type 2 diabetes mellitus on coronary microvascular function and myocardial perfusion in patients without obstructive coronary artery disease.

PURPOSE: We assessed the impact of type 2 diabetes, in the presence of other major cardiovascular risk factors, on coronary microvascular function and myocardial perfusion in patients without obstructive coronary artery disease (CAD). METHODS: In this prospective study, 23 patients with type 2 diabetes and 26 nondiabetic patients matched for age, sex and other cardiovascular risk factors underwent a cold pressure test (CPT) and dipyridamole transthoracic echocardiography to determine their coronary flow (CF) ratio. Within 2 weeks, all diabetic patients also underwent dipyridamole-rest myocardial perfusion single-photon emission (MPS) CT. None of the patients with or without diabetes had significant CAD on invasive coronary angiography. RESULTS: The CPT-CF ratio was significantly lower in diabetic patients than in nondiabetic patients (1.46 ± 0.26 vs. 1.71 ± 0.32, p = 0.006) and was correlated significantly with fasting glycaemia (r = -0.35, p = 0.01), but not with glycated haemoglobin. The dipyridamole-CF ratio was also lower in diabetic patients than in nondiabetic patients (2.38 ± 0.74 vs. 2.75 ± 0.49, p = 0.04). On MPS imaging, 5 diabetic patients (22%) had stress-induced ischaemia and the remaining 18 (78%) had normal myocardial perfusion. The dipyridamole-CF ratio was not different in patients with and without reversible defects (2.3 ± 1.1 vs. 2.4 ± 0.6, p = 0.97). CONCLUSION: Coronary microvascular function is impaired in type 2 diabetic patients without significant CAD, compared to nondiabetic patients with similar other cardiovascular risk factors. In the majority of diabetic patients, microvascular dysfunction is associated with normal myocardial perfusion.

Assessment of poststress left ventricular ejection fraction by gated SPECT: comparison with equilibrium radionuclide angiocardiography.

PURPOSE: We compared left ventricular (LV) ejection fraction obtained by gated SPECT with that obtained by equilibrium radionuclide angiocardiography in a large cohort of patients. METHODS: Within 1 week, 514 subjects with suspected or known coronary artery disease underwent same-day stress-rest (99m)Tc-sestamibi gated SPECT and radionuclide angiocardiography. For both studies, data were acquired 30 min after completion of exercise and after 3 h rest. RESULTS: In the overall study population, a good correlation between ejection fraction measured by gated SPECT and by radionuclide angiocardiography was observed at rest (r=0.82, p<0.0001) and after stress (r=0.83, p<0.0001). In Bland-Altman analysis, the mean differences in ejection fraction (radionuclide angiocardiography minus gated SPECT) were -0.6% at rest and 1.7% after stress. In subjects with normal perfusion (n=362), a good correlation between ejection fraction measured by gated SPECT and by radionuclide angiocardiography was observed at rest (r=0.72, p<0.0001) and after stress (r=0.70, p<0.0001) and the mean differences in ejection fraction were -0.9% at rest and 1.4% after stress. Also in patients with abnormal perfusion (n=152), a good correlation between the two techniques was observed both at rest (r=0.89, p<0.0001) and after stress (r=0.90, p<0.0001) and the mean differences in ejection fraction were 0.1% at rest and 2.5% after stress. CONCLUSION: In a large study population, a good agreement was observed in the evaluation of LV ejection fraction between gated SPECT and radionuclide angiocardiography. However, in patients with perfusion abnormalities, a slight underestimation in poststress LV ejection fraction was observed using gated SPECT as compared to equilibrium radionuclide angiocardiography.

64Cu-PSMA-617 PET/CT Imaging of Prostate Adenocarcinoma: First In-Human Studies.

AIM: The prostate-specific membrane antigen (PSMA) is a cell surface protein, which is overexpressed in nearly all cases of prostate cancer (PCa). PET imaging with 68Ga-PSMA-HBED-CC has recently found widespread application in the diagnosis of recurrent PCa. In this study, the diagnostic potential of 64Cu-labeled PSMA ligand (PSMA-617) PET in patients with PCa has been investigated. MATERIALS AND METHODS: The study was conducted simultaneously at two nuclear medicine centers, Austria (Vienna, Center 1) and Germany (Bad Berka, Center 2). The patients (n = 29) included in this study were referred for PET (Center 1, 21 patients) or PET/CT (Center 2, 8 patients) imaging with either a high suspicion of recurrent disease or for possible surgical or PSMA radioligand therapy planning. PET images of the whole body were performed at 1 hour p.i. and additional images of the pelvis at 2 hours p.i. RESULTS: In 23 of 29 patients, at least one focus of pathological tracer uptake suspicious for primary disease in the prostate lobe or recurrent disease was detected. Among healthy organs, the salivary glands, kidneys, and liver showed the highest radiotracer uptake. Lesions suspicious for PCa were detected with excellent contrast as early as 1 hour p.i. with high detection rates even at low prostate-specific antigen (PSA) levels. CONCLUSION: The preliminary results of this study demonstrate the high potential of 64Cu-PSMA ligand PET/CT imaging in patients with recurrent disease and in the primary staging of selected patients with progressive local disease. The acquired PET images showed an excellent resolution of the detected lesions with very high lesion-to- background contrast. Furthermore, the long half-life of 64Cu allows distribution of the tracer to clinical PET centers that lack radiochemistry facilities for the preparation of 68Ga-PSMA ligand (satellite concept).

Role of (64)CuCl 2 PET/CT in staging of prostate cancer.

AIM: The presence of an elevated copper concentration in cancer cells may be potentially used to differentiate healthy from transformed cells. In this study, we aimed to look at the possible role of (64)CuCl2 PET/CT in staging of patients with prostate cancer (PC). METHODS: Seven patients affected by histologically confirmed PC have been prospectively enrolled. Three patients underwent adrenal deprivation therapy (ADT) at time of imaging. The remaining four patients had no ADT, surgery, or external beam radiation therapy (EBRT). In all patients, up to three (64)CuCl2 PET/CT scans 10 min, 1 h and 3 h (and an additional scan 24 h in 2 patients) after administration of mean 339 MBq (64)CuCl2 were performed and analyzed for presence of disease. Additionally, dosimetric calculations were performed. All patients underwent a multiparametric magnetic resonance imaging (mMRI) for confirmation of disease. RESULTS: Lesions specifically in the pelvic area could be easily delineated, which was due to the absence of urinary excretion of the tracer. (64)CuCl2 uptake was higher in primary tumors of patients without ADT than in patients under bicalutamide therapy. In two patients with suspected lymphadenopathy at MRI (>10 mm diameter), there was no enhanced (64)CuCl2 uptake. In other two patients, there was focal enhanced uptake in involved pelvic lymph nodes, one of which with a normal size of <10 mm. CONCLUSIONS: The preliminary results of this study show a high uptake of (64)CuCl2 in PC and involved regional lymph nodes indicating to a great potential of (64)CuCl2 PET/CT for primary staging of patients with prostate cancer.