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Background: Angiogenesis has increasingly been a target for imaging and treatment over the last decade. The integrin αvβ3 is highly expressed in cells during angiogenesis and are therefore a promising target for imaging. In this study, we aimed to investigate the PET tracer [68Ga]Ga-RGD as a marker of angiogenesis following MI and its ability to predict cardiac functional parameters. Methods: First, the real-time interaction between [68Ga]Ga-RGD and integrin αvβ3 was investigated using surface plasmon resonance (SPR). Second, an animal study was performed to investigate the [68Ga]Ga-RGD uptake in the infarcted area after one and four weeks following MI in a rat model (MI = 68, sham surgery = 36). Finally, the specificity of the [68Ga]Ga-RGD tracer was evaluated ex vivo using histology, autoradiography, gamma counting and flow cytometry. Results: SPR showed that [68Ga]Ga-RGD has a high affinity for integrin αvβ3, forming a strong and stable binding. PET/CT showed a significantly higher uptake of [68Ga]Ga-RGD in the infarcted area compared to sham one week (p < 0.001) and four weeks (p < 0.001) after MI. The uptake of [68Ga]Ga-RGD after one week correlated to end diastolic volume (r = 0.74, p < 0.001) and ejection fraction (r = − 0.71, p < 0.001) after four weeks. Conclusion: This study demonstrates that [68Ga]Ga-RGD has a high affinity for integrin αvβ3, which enables the evaluation of angiogenesis and remodeling. The [68Ga]Ga-RGD uptake after one week indicates that [68Ga]Ga-RGD may be used as an early predictor of cardiac functional parameters and possible development of heart failure after MI. These encouraging data supports the clinical translation and future use in MI patients. [ABSTRACT FROM AUTHOR]

Background: Doxorubicin is the mainstay of curative lymphoma treatment but is associated with a dose-dependent cardiotoxicity that is often recognized too late to avoid substantial irreversible cardiac injury. Iodine-123 metaiodobenzylguanidine (123I-MIBG) is a gamma-emitting tracer that mimics noradrenaline uptake, storage, and release mechanisms in adrenergic presynaptic neurons. 123I-MIBG scintigraphy can be used for assessment of doxorubicin-induced injury to myocardial adrenergic neurons during treatment and could be the tool for early detection of doxorubicin cardiotoxicity, which is currently lacking.Methods and Results: A total of 37 lymphoma patients scheduled for doxorubicin treatment were included in our study. 123I-MIBG imaging was performed prior to chemotherapy and after a median of 4 cycles of doxorubicin. Early and late heart-to-mediastinum ratios (H/Mearly and H/Mlate) and washout rate (WOR) were used for evaluation of cardiotoxicity. The prognostic value of 123I-MIBG results was assessed using left ventricular ejection fraction (LVEF) as measured by cardiac magnetic resonance at 1-year follow-up. We found a post-therapy increase in WOR (including nine patients with > 10% increase), which was not statistically significant (18.6 vs 23.4%, P = 0.09). The difference appeared to be driven by an increase in H/Mearly. LVEF decreased from baseline to 1-year follow-up (64 vs 58%, P = 0.03). LVEF change was not associated with changes in WOR (P = 0.5).Conclusion: The present study does not provide evidence for 123I-MIBG imaging as a clinically applicable tool for early detection of doxorubicin-induced cardiotoxicity. [ABSTRACT FROM AUTHOR]

Background: Determining infarct size and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) is important when assessing the efficacy of new reperfusion strategies. We investigated whether rest 82Rb-PET myocardial perfusion imaging can estimate area at risk, final infarct size, and myocardial salvage index when compared to cardiac SPECT and magnetic resonance (CMR).Methods: Twelve STEMI patients were injected with 99mTc-Sestamibi intravenously immediate prior to reperfusion. SPECT, 82Rb-PET, and CMR imaging were performed post-reperfusion and at a 3-month follow-up. An automated algorithm determined area at risk, final infarct size, and hence myocardial salvage index.Results: SPECT, CMR, and PET were performed 2.2 ± 0.5, 34 ± 8.5, and 32 ± 24.4 h after reperfusion, respectively. Mean (± SD) area at risk were 35.2 ± 16.6%, 34.7 ± 11.3%, and 28.1 ± 16.1% of the left ventricle (LV) in SPECT, CMR, and PET, respectively, P = 0.04 for difference. Mean final infarct size estimates were 12.3 ± 15.4%, 13.7 ± 10.4%, and 11.9 ± 14.6% of the LV in SPECT, CMR, and PET imaging, respectively, P = .72. Myocardial salvage indices were 0.64 ± 0.33 (SPECT), 0.65 ± 0.20 (CMR), and 0.63 ± 0.28 (PET), (P = .78).Conclusions: 82Rb-PET underestimates area at risk in patients with STEMI when compared to SPECT and CMR. However, our findings suggest that PET imaging seems feasible when assessing the clinical important parameters of final infarct size and myocardial salvage index, although with great variability, in a selected STEMI population with large infarcts. These findings should be confirmed in a larger population. [ABSTRACT FROM AUTHOR]