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BackgroundWe measured myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) by a dynamic low-dose CZT-SPECT protocol in patients with suspected or known coronary artery disease (CAD) and investigated the capability of dynamic data in predicting obstructive CAD. A total of 173 patients with suspected or known CAD underwent dynamic CZT-SPECT after the injection of 155 MBq and 370 MBq of 99mTc-sestamibi for rest and stress imaging, respectively. Standard rest and stress imaging were performed at the end of each dynamic scan. A total perfusion defect (TPD) < 5% were considered normal. Obstructive CAD was defined as ≥ 70% stenosis at coronary angiography.ResultsGlobal MPR was lower (p < 0.05) in patients with abnormal compared with those with normal MPI (2.40 ± 0.7 vs. 2.70 ± 0.8). A weak, albeit significant correlation between TPD and MPR (r = − 0.179, p < 0.05) was found. In 91 patients with available angiographic data, hyperemic MBF (2.59 ± 1.2 vs. 3.24 ± 1.1 ml/min/g) and MPR (1.96 ± 0.7 vs. 2.74 ± 0.9) were lower (both p < 0.05) in patients with obstructive CAD (n = 21) compared with those without (n = 70). At univariable analysis, TPD, hyperemic MBF, and MPR were significant predictors of obstructive CAD, whereas only MPR was independent predictor at multivariable analysis (p < 0.05). At per vessels analysis, regional hyperemic MBF (2.59 ± 1.2 vs. 3.24 ± 1.1 ml/min/g) and regional MPR (1.96 ± 0.7 vs. 2.74 ± 0.9) were lower in the 31 vessels with obstructive CAD compared with 242 vessels without (both p < 0.05).ConclusionsIn patients with suspected or known CAD, MPR assessed by low-dose dynamic CZT-SPECT showed a good correlation with myocardial perfusion imaging findings and it could be useful to predict obstructive CAD.

PurposeWe assessed the effects of the COVID-19 pandemic on myocardial perfusion imaging (MPI) for ischemic heart disease during the lockdown imposed by the Italian Government.MethodsWe retrospectively reviewed the number and the findings of stress single-photon emission computed tomography (SPECT)-MPI performed between February and May 2020 during the COVID-19 pandemic at the University of Napoli Federico II. The number and the findings of stress SPECT-MPI studies acquired in the corresponding months of the years 2017, 2018, and 2019 were also evaluated for direct comparison.ResultsThe number of stress SPECT-MPI studies performed during the COVID-19 pandemic (n = 123) was significantly lower (P < 0.0001) compared with the mean yearly number of procedures performed in the corresponding months of the years 2017, 2018, and 2019 (n = 413). Yet, the percentage of abnormal stress SPECT-MPI studies was similar (P = 0.65) during the pandemic (36%) compared with the mean percentage value of the corresponding period of the years 2017, 2018, and 2019 (34%).ConclusionThe number of stress SPECT-MPI studies was significantly reduced during the COVID-19 pandemic compared with the corresponding months of the previous 3 years. The lack of difference in the prevalence of abnormal SPECT-MPI studies between the two study periods strongly suggests that many patients with potentially abnormal imaging test have been missed during the pandemic.

PurposeCardiac imaging with positron emission tomography/computed tomography (PET/CT) allows measurement of coronary artery calcium (CAC), stress-induced myocardial ischemia and myocardial perfusion reserve (MPR). We evaluated the prognostic role of the combined assessment of regional CAC score, ischemic total perfusion defect (ITPD) and MPR in predicting lesion-related outcome in patients with suspected coronary artery disease (CAD).MethodsWe studied 206 patients with suspected CAD referred to 82Rb PET/CT cardiac imaging and available coronary angiographic data. The outcome end points were cardiac death, target vessel-related myocardial infarction or coronary revascularization.ResultsCompared to vessels without event, those with event showed higher CAC score and ITPD, and lower hyperemic myocardial blood flow and MPR (all p < 0.001). At Cox regression multivariable analysis, significant CAD (≥50% stenosis) (p < 0.001), CAC score ≥ 300 (p < 0.01) and MPR <2 (p < 0.01) were independent predictors of events. The decision trees analysis for the identification of events produced five terminal nodes. The initial split was on CAC score values. For vessels with CAC <300 and MPR ≥2, no further split was performed, while vessels with CAC <300 and MPR <2 were further stratified by ITPD. For vessels with CAC ≥300 a further stratification was performed only by MPR. The worst prognosis was observed in vessels with CAC ≥300 and MPR <2 and in vessels with CAC <300, MPR <2 and ITPD ≥5%.ConclusionThe combination of CAC score and MPR is useful to predict the lesion-related outcome in the presence of significant CAD.

PurposeThe identification of coronary vascular dysfunction may enhance risk stratification in patients with resistant hypertension (RH). We evaluated if impaired coronary vascular function, assessed by rubidium-82 (82Rb) positron emission tomography/computed tomography (PET/CT) imaging, is associated with increased cardiovascular risk in patients with hypertension without overt coronary artery disease (CAD).MethodsWe studied 517 hypertensive subjects, 26% with RH, without overt CAD, and with normal stress-rest myocardial perfusion imaging at 82Rb PET/CT. The outcome end points were cardiac death, nonfatal myocardial infarction, coronary revascularization, and admission for heart failure.ResultsOver a median of 38 months (interquartile range 26 to 50), 21 cardiac events (4.1% cumulative event rate) occurred. Patients with RH were older (p < 0.05) and had a higher prevalence of left ventricular hypertrophy (p < 0.001), a lower hyperemic myocardial blood flow (MBF), and myocardial perfusion reserve (MPR) (both p < 0.001) compared to those without. Conversely, coronary artery calcium content and baseline MBF were not different between patients with and without RH. At univariable Cox regression analysis, age, RH, left ventricular ejection fraction, coronary artery calcium score, and reduced MPR were significant predictors of events. At multivariable analysis, age, RH, and reduced MPR (all p < 0.05) were independent predictors of events. Patients with RH and reduced MPR had the highest risk of events and the major risk acceleration over time.ConclusionThe findings suggest that the assessment of coronary vascular function may enhance risk stratification in patients with hypertension.

Purpose We assessed the impact of COVID-19 infection on cardiovascular events in patients with suspected or known coronary artery disease (CAD) referred to stress single-photon emission computed tomography myocardial perfusion imaging (MPS). Methods A total of 960 consecutive patients with suspected or known CAD were submitted by referring physicians to stress MPS for assessment of myocardial ischemia between January 2018 and June 2019. All patients underwent stress-optional rest MPS. Perfusion defects were quantitated as % of LV myocardium and expressed as total perfusion defect (TPD), representing the defect extent and severity. A TPD ≥ 5% was considered abnormal. Results During a mean follow-up of 27 months (range 4–38) 31 events occurred. Moreover, 55 (6%) patients had a COVID-19 infection. The median time from index MPS to COVID-19 infection was 16 months (range 6–24). At Cox multivariable analysis, abnormal MPS and COVID-19 infection resulted as independent predictors of events. There were no significant differences in annualized event rate in COVID-19 patients with or without abnormal MPS ( p  = 0.56). Differently, in patients without COVID-19, the presence of abnormal MPS was associated with higher event rate ( p  < .001). Patients with infection compared to those without had a higher event rate in the presence of both normal and abnormal TPD. Conclusion In patients with suspected or known CAD, the presence of COVID-19 infection during a short-term follow-up was associated with a higher rate of cardiovascular events.

Few studies using Positron Emission Tomography with 18F-fluorodeoxyglucose (18F-FDG-PET) have examined the neurobiological basis of antipsychotic resistance in schizophrenia, primarily focusing on metabolic activity, with none investigating connectivity patterns. Here, we aimed to explore differential patterns of glucose metabolism between patients and controls (CTRL) through a graph theory-based approach and network comparison tests. PET scans with 18F-FDG were obtained by 70 subjects, 26 with treatment-resistant schizophrenia (TRS), 28 patients responsive to antipsychotics (nTRS), and 16 CTRL. Relative brain glucose metabolism maps were processed in the automated anatomical labeling (AAL)-Merged atlas template. Inter-subject connectivity matrices were derived using Gaussian Graphical Models and group networks were compared through permutation testing. A logistic model based on machine-learning was employed to estimate the association between the metabolic signals of brain regions and treatment resistance. To account for the potential influence of antipsychotic medication, we incorporated chlorpromazine equivalents as a covariate in the network analysis during partial correlation calculations. Additionally, the machine-learning analysis employed medication dose-stratified folds. Global reduced connectivity was detected in the nTRS (p-value = 0.008) and TRS groups (p-value = 0.001) compared to CTRL, with prominent alterations localized in the frontal lobe, Default Mode Network, and dorsal dopamine pathway. Disruptions in frontotemporal and striatal-cortical connectivity were detected in TRS but not nTRS patients. After adjusting for antipsychotic doses, alterations in the anterior cingulate, frontal and temporal gyri, hippocampus, and precuneus also emerged. The machine-learning approach demonstrated an accuracy ranging from 0.72 to 0.8 in detecting the TRS condition.

BackgroundA normal stress myocardial perfusion single-photon emission computed tomography (MPS) is associated with a good clinical outcome. New iterative algorithms, such as wide beam reconstruction (WBR), which improve image interpretation with half-dose or half-time acquisition, have been proposed for cardiac MPS. The aim of this study was to assess the long-term predictive value of a low-dose normal stress-only MPS with WBR using conventional Anger camera in patients with known or suspected coronary artery disease (CAD).Methods and ResultsA total of 2106 patients with known or suspected CAD and normal perfusion at half-dose stress-only MPS protocol were followed for a mean of 6.6 ± 2.7 years. MPS data were reconstructed with WBR iterative algorithm. End-point events were cardiac death or nonfatal myocardial infarction. Noncardiac death was considered the competing event. During follow-up, 149 cardiac events occurred with an annualized event rate of 1.2%. Independent predictors of cardiac events at Cox analysis were age, male gender, diabetes mellitus, previous myocardial infarction and the need for pharmacologic stress testing. At Fine-Gray analysis the cumulative incidence of cardiac events progressively increases with age and in the presence of diabetes for any combination of gender and stress type. Survival tree analysis confirmed that long-term prognosis considerably varies according of risk factors profile.ConclusionsLow-dose normal stress-only WBR MPS has a reliable long-term prognostic value in patients with suspected or known CAD. This finding supports the introduction of such a method into clinical practice with a consistent dose optimization in the interest of patients and exposed staff.

Aims18F-FDG PET/CT is the most accurate imaging modality in differentiated thyroid cancer (DTC) patients with either an aggressive histology, an absence of radioiodine uptake in neoplastic foci, or in the absence of imaging abnormalities in patients with an elevated serum thyroglobulin (Tg) level that progresses with time. We evaluated the diagnostic performance of FDG PET/MR in comparison with that of PET/CT.Methods and resultsFollowing the injection of a single 18F-FDG activity, PET/MR and PET/CT were sequentially performed in 40 consecutive patients with DTC previously treated with total thyroidectomy and radioiodine ablation. All patients were then followed up for at least 6 months. PET/MR was positive in 11 patients and PET/CT in 10. PET/MR detected 33 tumor foci and PET/CT 30. During the follow-up of the 12 patients with negative initial PET studies and with a detectable serum Tg, only one patient had a neck recurrence and the administration of an empiric high activity of 131I in the other 11 patients did not reveal any tumor focus. In the 17 patients with an initial serum Tg level < 2 ng/mL, no recurrence occurred.ConclusionThis study confirms the high diagnostic accuracy of FDG PET studies in DTC patients with elevated serum Tg levels and shows that PET/MR brings similar information as compared to PET/CT imaging.

Background: The prevalence of traditional cardiovascular risk factors shows different age-specific patterns. It is not known whether the prognostic impact of risk factors is similarly age-specific. We evaluated the profiles of cardiovascular risk factors and their prognostic impact on coronary artery disease (CAD) in relation to age. Methods: We included 3667 patients with suspected or known CAD undergoing stress myocardial perfusion imaging (MPI). We evaluated the risk for major adverse cardiac events (MACE) within three years from the index MPI in patients belonging to three groups according to age tertile distribution: <59, 59–68, and >68 years. Gender, body mass index, diabetes, hypertension, dyslipidemia, family history of CAD, smoking, angina, dyspnea, previous CAD, and MPI outcome were assessed as risk factors by a multivariable Cox’s regression. Results: The three-year risk of MACE increased progressively with age and was 9%, 13%, and 18% for each group, respectively (p < 0.0001). Dyspnea and abnormal MPI outcome were significant risk factors for all age groups. Diabetes and smoking were significant from the age of 59 onwards, while hypertension resulted significant for patients older than 68 years. Conclusions: The number of risk factors was significantly associated with the occurrence of MACE increase with age. It is noteworthy that a personal history of CAD was not useful for risk stratification, while MPI results were.