<div><h4>Performance of 8- vs 16 ECG-gated reconstructions in assessing myocardial function using Rubidium-82 myocardial perfusion imaging: Findings in a young, healthy population.</h4><i>Lassen ML, Wissenberg M, Byrne C, Kjaer A, Hasbak P</i><br /><b>Background</b><br />Current imaging guidelines recommend using at least 16 ECG gates when performing MUGA and cardiac SPECT to assess left ventricular ejection fraction (LVEF). However, for Rubidium-82 (<sup>82</sup>Rb) PET, 8 ECG-gated reconstructions have been a mainstay. This study investigated the implications of quantitative assessments when employing 16 gate, instead of 8 gate, reconstructions for <sup>82</sup>Rb myocardial perfusion imaging (MPI).<br /><b>Methods</b><br />The study comprised 25 healthy volunteers (median age 23 years) who underwent repeat MPI sessions employing <sup>82</sup>Rb PET/CT. We report LVEF, its reserve (stress LVEF - rest LVEF), and their repeatability measures (RMS method) obtained for 8- and 16 ECG-gated reconstructions.<br /><b>Results</b><br />Similar LVEF and LVEF reserve estimates were found for the 8- and 16-gated reconstructions ([%] LVEF (8/16 gates): rest = 61 ± 6/64 ± 6, stress = 68 ± 7/71 ± 6, LVEF reserve (8/16 gates): 8 ± 3/6 ± 4, and all P ≥ 0.13). Similar test-retest repeatability measures were observed for rest and stress LVEF and their reserves [LVEF (8/16 gates); Rest = 4.5/4.6 (P = 0.81), Stress = 3.5/3.2 (P = 0.33), LVEF reserve = 46.7/49.3 (P = 0.13)].<br /><b>Conclusion</b><br />In healthy subjects, 8 and 16 ECG gates can be used interchangeably if only volumetric assessments are desired. However, if filling and emptying rates are of interest, a minimum of 16 ECG gates should be employed.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 28 Jan 2023; epub ahead of print</small></div>

<div><h4>A retrospective evaluation of Bayesian-penalized likelihood reconstruction for [O]HO myocardial perfusion imaging.</h4><i>Siekkinen R, Han C, Maaniitty T, Teräs M, ... Saraste A, Teuho J</i><br /><b>Background</b><br />New Block-Sequential-Regularized-Expectation-Maximization (BSREM) image reconstruction technique has been introduced for clinical use mainly for oncologic use. Accurate and quantitative image reconstruction is essential in myocardial perfusion imaging with positron emission tomography (PET) as it utilizes absolute quantitation of myocardial blood flow (MBF). The aim of the study was to evaluate BSREM reconstruction for quantitation in patients with suspected coronary artery disease (CAD).<br /><b>Methods and results</b><br />We analyzed cardiac [<sup>15</sup>O]H<sub>2</sub>O PET studies of 177 patients evaluated for CAD. Differences between BSREM and Ordered-Subset-Expectation-Maximization with Time-Of-Flight (TOF) and Point-Spread-Function (PSF) modeling (OSEM-TOF-PSF) in terms of MBF, perfusable tissue fraction, and vascular volume fraction were measured. Classification of ischemia was assessed between the algorithms. OSEM-TOF-PSF and BSREM provided similar global stress MBF in patients with ischemia (1.84 ± 0.21 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup> vs 1.86 ± 0.21 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup>) and no ischemia (3.26 ± 0.34 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup> vs 3.28 ± 0.34 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup>). Global resting MBF was also similar (0.97 ± 0.12 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup> and 1.12 ± 0.06 g⋅ml<sup>-1</sup>⋅min<sup>-1</sup>). The largest mean relative difference in MBF values was 7%. Presence of myocardial ischemia was classified concordantly in 99% of patients using OSEM-TOF-PSF and BSREM reconstructions <br /><b>Conclusion:</b><br/>OSEM-TOF-PSF and BSREM image reconstructions produce similar MBF values and diagnosis of myocardial ischemia in patients undergoing [<sup>15</sup>O]H<sub>2</sub>O PET due to suspected obstructive coronary artery disease.<br /><br />© 2023. The Author(s).<br /><br /><small>J Nucl Cardiol: 19 Jan 2023; epub ahead of print</small></div>

<div><h4>Relationship between impaired myocardial blood flow by positron emission tomography and low-attenuation plaque burden and pericoronary adipose tissue attenuation from coronary computed tomography: From the prospective PACIFIC trial.</h4><i>Kuronuma K, van Diemen PA, Han D, Lin A, ... Dey D, Knaapen P</i><br /><b>Background</b><br />Positron emission tomography (PET) is the clinical gold standard for quantifying myocardial blood flow (MBF). Pericoronary adipose tissue (PCAT) attenuation may detect vascular inflammation indirectly. We examined the relationship between MBF by PET and plaque burden and PCAT on coronary CT angiography (CCTA).<br /><b>Methods</b><br />This post hoc analysis of the PACIFIC trial included 208 patients with suspected coronary artery disease (CAD) who underwent [<sup>15</sup>O]H<sub>2</sub>O PET and CCTA. Low-attenuation plaque (LAP, < 30HU), non-calcified plaque (NCP), and PCAT attenuation were measured by CCTA.<br /><b>Results</b><br />In 582 vessels, 211 (36.3%) had impaired per-vessel hyperemic MBF (≤ 2.30 mL/min/g). In multivariable analysis, LAP burden was independently and consistently associated with impaired hyperemic MBF (P = 0.016); over NCP burden (P = 0.997). Addition of LAP burden improved predictive performance for impaired hyperemic MBF from a model with CAD severity and calcified plaque burden (P < 0.001). There was no correlation between PCAT attenuation and hyperemic MBF (r = - 0.11), and PCAT attenuation was not associated with impaired hyperemic MBF in univariable or multivariable analysis of all vessels (P > 0.1).<br /><b>Conclusion</b><br />In patients with stable CAD, LAP burden was independently associated with impaired hyperemic MBF and a stronger predictor of impaired hyperemic MBF than NCP burden. There was no association between PCAT attenuation and hyperemic MBF.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 16 Jan 2023; epub ahead of print</small></div>

<div><h4>Prednisone vs methotrexate in treatment naïve cardiac sarcoidosis.</h4><i>Vis R, Mathijssen H, Keijsers RGM, van de Garde EMW, ... Post MC, Grutters JC</i><br /><b>Background</b><br />Side effects limit the long-term use of glucocorticoids in cardiac sarcoidosis (CS), and methotrexate has gained attention as steroid sparing agent although the supporting evidence is poor. This study compared prednisone monotherapy, methotrexate monotherapy or a combination of both, in the reduction of myocardial Fluorine-18 fluorodeoxyglucose (FDG) uptake and clinical stabilization of CS patients.<br /><b>Methods and results</b><br />In this retrospective cohort study, 61 newly diagnosed and treatment naïve CS patients commenced treatment with prednisone (N = 21), methotrexate (N = 30) or prednisone and methotrexate (N = 10) between January 2010 and December 2017. Primary outcome was metabolic response on FDG PET/CT and secondary outcomes were treatment patterns, major adverse cardiovascular events, left ventricular ejection fraction, biomarkers and side effects. At a median treatment duration of 6.2 [5.7-7.2] months, 71.4% of patients were FDG PET/CT responders, and the overall myocardial maximum standardized uptake value decreased from 6.9 [5.0-10.1] to 3.4 [2.1-4.7] (P < 0.001), with no significant differences between treatment groups. During 24 months of follow-up, 7 patients (33.3%; prednisone), 6 patients (20.0%; methotrexate) and 1 patient (10.0%; combination group) experienced at least one major adverse cardiovascular event (P = 0.292). Left ventricular ejection fraction was preserved in all treatment groups.<br /><b>Conclusions</b><br />Significant suppression of cardiac FDG uptake occurred in CS patients after 6 months of prednisone, methotrexate or combination therapy. There were no significant differences in clinical outcomes during follow-up. These results warrant further investigation of methotrexate treatment in CS patients.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 14 Jan 2023; epub ahead of print</small></div>

<div><h4>Does financial hardship associate with abnormal quantitative myocardial perfusion and major adverse cardiovascular event?</h4><i>Kitkungvan D, Johnson NP, Bui L, Patel MB, ... Hood S, Gould KL</i><br /><b>Background</b><br />Data on impact of financial hardship on coronary artery disease (CAD) remain incomplete.<br /><b>Methods</b><br />Consecutive subjects referred for clinical rest/stress cardiac positron emission tomography (PET) were enrolled. Financial hardship is defined as patients\' inability to pay for their out-of-pocket expense for cardiac PET. Abnormal cardiac PET is defined as at least moderate relative perfusion defects at stress involving > 10% of the left ventricle or global coronary flow reserve ≤ 2.0. Patients were followed for major adverse cardiovascular event (MACE) comprised of all-cause mortality, non-fatal myocardial infarction, and late coronary revascularization.<br /><b>Results</b><br />We analyzed a total of 4173 patients with mean age 65.6 ± 11.3 years, 72.2% men, and 93.6% reported as having medical insurance. Of these, 504 (12.1%) patients had financial hardship. On multivariable analysis, financial hardship associated with abnormal cardiac PET (odds ratio 1.377, p = 0.004) and MACE (hazard ratio 1.432, p = 0.010) and its association with MACE was mostly through direct effect with small proportion mediated by abnormal cardiac PET or known CAD.<br /><b>Conclusion</b><br />Among patients referred for cardiac rest/stress PET, financial hardship independently associates with myocardial perfusion abnormalities and MACE; however, its effect on MACE is largely not mediated by abnormal myocardial perfusion or known CAD suggesting distinct impact of financial hardship beyond traditional risk factors and CAD that deserves attention and intervention to effectively reduced adverse outcomes. Having medical insurance does not consistently protect from financial hardship and a more preventive-oriented restructuring may provide better outcomes at lower cost.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 13 Jan 2023; epub ahead of print</small></div>

<div><h4>Machine learning based model to diagnose obstructive coronary artery disease using calcium scoring, PET imaging, and clinical data.</h4><i>van Dalen JA, Koenders SS, Metselaar RJ, Vendel BN, ... Slump CH, van Dijk JD</i><br /><b>Introduction</b><br />Accurate risk stratification in patients with suspected stable coronary artery disease is essential for choosing an appropriate treatment strategy. Our aim was to develop and validate a machine learning (ML) based model to diagnose obstructive CAD (oCAD).<br /><b>Method</b><br />We retrospectively have included 1007 patients without a prior history of CAD who underwent CT-based calcium scoring (CACS) and a Rubidium-82 PET scan. The entire dataset was split 4:1 into a training and test dataset. An ML model was developed on the training set using fivefold stratified cross-validation. The test dataset was used to compare the performance of expert readers to the model. The primary endpoint was oCAD on invasive coronary angiography (ICA).<br /><b>Results</b><br />ROC curve analysis showed an AUC of 0.92 (95% CI 0.90-0.94) for the training dataset and 0.89 (95% CI 0.84-0.93) for the test dataset. The ML model showed no significant differences as compared to the expert readers (p ≥ 0.03) in accuracy (89% vs. 88%), sensitivity (68% vs. 69%), and specificity (92% vs. 90%).<br /><b>Conclusion</b><br />The ML model resulted in a similar diagnostic performance as compared to expert readers, and may be deployed as a risk stratification tool for obstructive CAD. This study showed that utilization of ML is promising in the diagnosis of obstructive CAD.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 09 Jan 2023; epub ahead of print</small></div>

<div><h4>The power of zero calcium in 82-Rubidium PET irrespective of sex and age.</h4><i>Frey SM, Clerc OF, Honegger U, Amrein M, ... Müller CE, Zellweger MJ</i><br /><b>Background</b><br />Despite clinical suspicion, many non-invasive tests for coronary artery disease (CAD) are normal. Coronary artery calcification score (CACS) is a well-validated method to detect and risk stratify CAD. Patients with zero calcium score (ZCS) rarely have abnormal tests. Therefore, aims were to evaluate CACS as a gatekeeper to further functional downstream testing for CAD and estimate potential radiation and cost savings.<br /><b>Methods</b><br />Consecutive patients with suspected CAD referred for PET were included (n = 2640). Prevalence and test characteristics of ZCS were calculated in different groups. Summed stress score ≥ 4 was considered abnormal and summed difference score ≥ 7 equivalent to ≥ 10% ischemia. To estimate potential radiation/cost reduction, PET scans were hypothetically omitted in ZCS patients.<br /><b>Results</b><br />Mean age was 65 ± 11 years, 46% were female. 21% scans were abnormal and 26% of patients had ZCS. CACS was higher in abnormal PET (median 561 vs 27, P < 0.001). Abnormal PET was significantly less frequent in ZCS patients (2.6% vs 27.6%, P < 0.001). Sensitivity/negative predictive value (NPV) of ZCS to detect/exclude abnormal PET and ≥ 10% ischemia were 96.8% (95%-CI 95.0%-97.9%)/97.4% (95.9%-98.3%) and 98.9% (96.7%-99.6%)/99.6% (98.7%-99.9%), respectively. Radiation and cost reduction were estimated to be 23% and 22%, respectively.<br /><b>Conclusions</b><br />ZCS is frequent, and most often consistent with normal PET scans. ZCS offers an excellent NPV to exclude an abnormal PET and ≥ 10% ischemia across different gender and age groups. CACS is a suitable gatekeeper before advanced cardiac imaging, and potential radiation/cost savings are substantial. However, further studies including safety endpoints are needed.<br /><br />© 2023. The Author(s).<br /><br /><small>J Nucl Cardiol: 09 Jan 2023; epub ahead of print</small></div>

<div><h4>Splenic switch-off in regadenoson Rb-PET myocardial perfusion imaging: assessment of clinical utility.</h4><i>Saad JM, Ahmed AI, Han Y, El Nihum LI, ... Nabi F, Al-Mallah MH</i><br /><b>Background</b><br />Splenic switch-off (SSO) is a phenomenon describing a decrease in splenic radiotracer uptake after vasodilatory stress. We aimed to assess the diagnostic utility of regadenoson-induced SSO.<br /><b>Methods</b><br />We included consecutive patients who had clinically indicated Regadenoson Rb-82 PET-MPI for suspected CAD. This derivation cohort (no perfusion defects and myocardial flow reserves (MFR) ≥ 2) was used to calculate the splenic response ratio (SRR). The validation cohort was defined as patients who underwent both PET-MPI studies and invasive coronary angiography (ICA).<br /><b>Results</b><br />The derivation cohort (n = 100, 57.4 ± 11.6 years, 77% female) showed a decrease in splenic uptake from rest to stress (79.9 ± 16.8 kBq⋅mL vs 69.1 ± 16.2 kBq⋅mL, P < .001). From the validation cohort (n = 315, 66.3 ± 10.4 years, 67% male), 28% (via SRR = 0.88) and 15% (visually) were classified as splenic non-responders. MFR was lower in non-responders (SRR; 1.55 ± 0.65 vs 1.76 ± 0.78, P = .02 and visually; 1.18 ± 0.33 vs 1.79 ± 0.77, P < .001). Based on ICA, non-responders were more likely to note obstructive epicardial disease with normal PET scans especially in patients with MFR < 1.5 (SRR; 61% vs 34% P = .05 and visually; 68% vs 33%, P = .01).<br /><b>Conclusion</b><br />Lack of splenic response based on visual or quantitative assessment of SSO may be used to identify an inadequate vasodilatory response.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 06 Jan 2023; epub ahead of print</small></div>

<div><h4>Extracardiac findings with increased perfusion during clinical O-15-HO PET/CT myocardial perfusion imaging: A case series.</h4><i>Jochumsen MR, Overgaard DL, Vendelbo MH, Madsen MA, ... Gormsen LC, Barkholt TØ</i><br /><b>Background</b><br />Coincidental extracardiac findings with increased perfusion were reported during myocardial perfusion imaging (MPI) with various retention radiotracers. Clinical parametric O-15-H<sub>2</sub>O PET MPI yielding quantitative measures of myocardial blood flow (MBF) was recently implemented at our facility. We aim to explore whether similar extracardiac findings are observed using O-15-H<sub>2</sub>O.<br /><b>Methods and results</b><br />All patients (2963) were scanned with O-15-H<sub>2</sub>O PET MPI according to international guidelines and extracardiac findings were collected. In contrast to parametric O-15-H<sub>2</sub>O MBF images, extracardiac perfusion was assessed using summed images. Biopsy histopathology and other imaging modalities served as reference standards. Various malignant lesions with increased perfusion were detected, including lymphomas, large-celled neuroendocrine tumour, breast, and lung cancer plus metastases from colonic and renal cell carcinomas. Furthermore, inflammatory and hyperplastic benign conditions with increased perfusion were observed: rib fractures, gynecomastia, atelectasis, sarcoidosis, pneumonia, chronic lung inflammation and fibrosis, benign lung nodule, chronic diffuse lung infiltrates, pleural plaques and COVID-19 infiltrates.<br /><b>Conclusions</b><br />Malignant and benign extracardiac coincidental findings with increased perfusion are readily visible and frequently seen on O-15-H<sub>2</sub>O PET MPI. We recommend evaluating the summed O-15-H<sub>2</sub>O PET images in addition to the low-dose CT attenuation images.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 05 Jan 2023; epub ahead of print</small></div>

<div><h4>Radiomics for the detection of diffusely impaired myocardial perfusion: A proof-of-concept study using 13N-ammonia positron emission tomography.</h4><i>Degtiarova G, Garefa C, Boehm R, Ciancone D, ... Kaufmann PA, Buechel RR</i><br /><b>Aim</b><br />The current proof-of-concept study investigates the value of radiomic features from normal 13N-ammonia positron emission tomography (PET) myocardial retention images to identify patients with reduced global myocardial flow reserve (MFR).<br /><b>Methods</b><br />Data from 100 patients with normal retention 13N-ammonia PET scans were divided into two groups, according to global MFR (i.e., < 2 and ≥ 2), as derived from quantitative PET analysis. We extracted radiomic features from retention images at each of five different gray-level (GL) discretization (8, 16, 32, 64, and 128 bins). Outcome independent and dependent feature selection and subsequent univariate and multivariate analyses was performed to identify image features predicting reduced global MFR.<br /><b>Results</b><br />A total of 475 radiomic features were extracted per patient. Outcome independent and dependent feature selection resulted in a remainder of 35 features. Discretization at 16 bins (GL16) yielded the highest number of significant predictors of reduced MFR and was chosen for the final analysis. GLRLM_GLNU was the most robust parameter and at a cut-off of 948 yielded an accuracy, sensitivity, specificity, negative and positive predictive value of 67%, 74%, 58%, 64%, and 69%, respectively, to detect diffusely impaired myocardial perfusion.<br /><b>Conclusion</b><br />A single radiomic feature (GLRLM_GLNU) extracted from visually normal 13N-ammonia PET retention images independently predicts reduced global MFR with moderate accuracy. This concept could potentially be applied to other myocardial perfusion imaging modalities based purely on relative distribution patterns to allow for better detection of diffuse disease.<br /><br />© 2023. The Author(s).<br /><br /><small>J Nucl Cardiol: 05 Jan 2023; epub ahead of print</small></div>

<div><h4>Measuring myocardial blood flow using dynamic myocardial perfusion SPECT: artifacts and pitfalls.</h4><i>Mallet F, Poitrasson-Rivière A, Mariano-Goulart D, Agostini D, Manrique A</i><br /><AbstractText>Dynamic acquisition allows absolute quantification of myocardial perfusion and flow reserve, offering an alternative to overcome the potential limits of relative quantification, especially in patients with balanced multivessel coronary artery disease. SPECT myocardial perfusion is widely available, at lower cost than PET. Dynamic cardiac SPECT is now feasible and has the potential to be the next step of comprehensive perfusion imaging. In order to help nuclear cardiologists potentially interested in using dynamic perfusion SPECT, we sought to review the different steps of acquisition, processing, and reporting of dynamic SPECT studies in order to enlighten the potentially critical pitfalls and artifacts. Both patient-related and technical artifacts are discussed. Key parameters of the acquisition include pharmacological stress, radiopharmaceuticals, and injection device. When it comes to image processing, attention must be paid to image-derived input function, patient motion, and extra-cardiac activity. This review also mentions compartment models, cameras, and attenuation correction. Finally, published data enlighten some facets of dynamic cardiac SPECT while several issues remain. Harmonizing acquisition and quality control procedures will likely improve its performance and clinical strength.</AbstractText><br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 04 Jan 2023; epub ahead of print</small></div>

<div><h4>External validation and update of the J-ACCESS model in an Italian cohort of patients undergoing stress myocardial perfusion imaging.</h4><i>Petretta M, Megna R, Assante R, Zampella E, ... Acampa W, Cuocolo A</i><br /><b>Background</b><br />Cardiovascular risk models are based on traditional risk factors and investigations such as imaging tests. External validation is important to determine reproducibility and generalizability of a prediction model. We performed an external validation of t the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT (J-ACCESS) model, developed from a cohort of patients undergoing stress myocardial perfusion imaging.<br /><b>Methods</b><br />We included 3623 patients with suspected or known coronary artery disease undergoing stress single-photon emission computer tomography (SPECT) myocardial perfusion imaging at our academic center between January 2001 and December 2019.<br /><b>Results</b><br />In our study population, the J-ACCESS model underestimated the risk of major adverse cardiac events (cardiac death, nonfatal myocardial infarction, and severe heart failure requiring hospitalization) within three-year follow-up. The recalibrations and updated of the model slightly improved the initial performance: C-statistics increased from 0.664 to 0.666 and Brier score decreased from 0.075 to 0.073. Hosmer-Lemeshow test indicated a logistic regression fit only for the calibration slope (P = .45) and updated model (P = .22). In the update model, the intercept, diabetes, and severity of myocardial perfusion defects categorized coefficients were comparable with J-ACCESS.<br /><b>Conclusion</b><br />The external validation of the J-ACCESS model as well as recalibration models have a limited value for predicting of three-year major adverse cardiac events in our patients. The performance in predicting risk of the updated model resulted superimposable to the calibration slope model.<br /><br />© 2023. The Author(s).<br /><br /><small>J Nucl Cardiol: 04 Jan 2023; epub ahead of print</small></div>

<div><h4>Prognostic value of myocardial flow reserve derived by quantitative SPECT for patients with intermediate coronary stenoses.</h4><i>Sun R, Ma R, Wang M, Han K, ... Wang L, Fang W</i><br /><b>Background</b><br />Functional assessment of myocardial ischemia is critical for patients with intermediate coronary stenosis. As the diagnosis performance of absolute quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) by single-photon emission tomography (SPECT) has been proven, its prognostic value in patients with intermediate coronary stenosis remains to be evaluated.<br /><b>Methods</b><br />Patients with one or more target lesions of ≥ 50% to ≤ 80% diameter stenoses on invasive coronary angiography were prospectively included in this study. All patients were scheduled for clinically indicated SPECT myocardial perfusion imaging (MPI) within 3 months and agreed to provide informed consent to participate in quantitative SPECT acquisitions to obtain MBF and MFR values. The primary endpoint was defined as a composite of the major adverse cardiac events (MACE): Cardiac death, myocardial infarction, late revascularization and heart failure or unstable angina-related rehospitalization.<br /><b>Results</b><br />One hundred and nineteen patients (mean age 57 ± 8 years, 62.2% men) were included in the analysis. The average lumen stenosis of patients was 67.0 ± 10.4%. Over a median follow-up duration of 1408 days (interquartile range 1297-1666 days), 18 patients (15.1%) had MACE. Patients with impaired MFR (MFR < 2) had a significantly higher incidence of events than those with preserved MFR (MFR ≥ 2) in Kaplan-Meier survival analysis (Log-rank = 8.105, P = 0.004), while no significant difference was found between patients with normal relative perfusion and those with relative perfusion abnormalities (log-rank = 0.098, P > 0.05). In a multivariate Cox hazards analysis, the SPECT-derived MFR remained an independent predictor of MACE (HR 0.352, 95% CI 0.145-0.854, P = 0.021).<br /><b>Conclusions</b><br />In a cohort of patients with angiographic intermediate coronary lesions, SPECT-derived MFR was an independent predictor of prognosis.<br /><br />© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 02 Jan 2023; epub ahead of print</small></div>

<div><h4>Comparison of the prognostic value of impaired stress myocardial blood flow, myocardial flow reserve, and myocardial flow capacity on low-dose Rubidium-82 SiPM PET/CT.</h4><i>Dietz M, Kamani CH, Allenbach G, Rubimbura V, ... Muller O, Prior JO</i><br /><b>Background</b><br />The most reliable quantitative variable on Rubidium-82 (<sup>82</sup>Rb) cardiac PET/CT for predicting major adverse cardiovascular events (MACE) has not been characterized with low-dose silicon photomultipliers (SiPM) technology, which allows halving injected activity and radiation dose delivering less than 1.0 mSv in a 70-kg individual.<br /><b>Methods and results</b><br />We prospectively enrolled 234 consecutive participants with suspected myocardial ischemia. Participants underwent <sup>82</sup>Rb cardiac SiPM PET/CT (5 MBq/kg) and were followed up for MACE over 652 days (interquartile range 559-751 days). For each participant, global stress myocardial blood flow (stress MBF), global myocardial flow reserve (MFR), and regional severely reduced myocardial flow capacity (MFC<sub>severe</sub>) were measured. The Youden index was used to select optimal thresholds. In multivariate analysis after adjustments for clinical risk factors, reduced global stress MBF < 1.94 ml/min/g, reduced global MFR < 1.98, and regional MFC<sub>severe</sub> > 3.2% of left ventricle emerged all as independent predictors of MACE (HR 4.5, 3.1, and 3.67, respectively, p < 0.001). However, only reduced global stress MBF remained an independent prognostic factor for MACE after adjusting for clinical risk factors and the combined use of global stress MBF, global MFR, and regional MFC<sub>severe</sub> impairments (HR 2.81, p = 0.027).<br /><b>Conclusion</b><br />Using the latest SiPM PET technology with low-dose <sup>82</sup>Rb halving the standard activity to deliver < 1 mSv for a 70-kg patient, impaired global stress MBF, global MFR, and regional MFC were powerful predictors of cardiovascular events, outperforming traditional cardiovascular risk factors. However, only reduced global stress MBF independently predicted MACE, being superior to global MFR and regional MFC impairments.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 27 Dec 2022; epub ahead of print</small></div>

<div><h4>Diagnostic value of heart-to-mediastinum ratio in Tc-pyrophospate SPECT/CT for transthyretin cardiac amyloidosis.</h4><i>Ikoma T, Ohtani H, Ohno K, Iguchi K, ... Goshima S, Maekawa Y</i><br /><b>Background</b><br />In transthyretin cardiac amyloidosis (ATTR-CA), <sup>99m</sup>Tc-pyrophosphate myocardial scintigraphy (<sup>99m</sup>Tc-PYP) is a diagnostic tool that utilizes visual and quantitative evaluation. However, false positive cases can occur because of tracer accumulation in the blood. We investigated the effectiveness of the heart-to-mediastinum (H/M) ratio of <sup>99m</sup>Tc-PYP in ATTR-CA diagnosis.<br /><b>Methods</b><br />We retrospectively included 164 patients who underwent <sup>99m</sup>Tc-PYP single-photon emission computed tomography/computed tomography between March 2019 and January 2022. The diagnostic accuracy of ATTR-CA was examined by the heart-to-contralateral lung (H/CL) and H/M ratio calculated at 3 hours post-tracer administration.<br /><b>Results</b><br />After the exclusion of patients who did not undergo endomyocardial biopsy, 30 patients (15 each with ATTR-CA and without ATTR-CA) were included. The receiver operating characteristic curve used to distinguish ATTR-CA from non-ATTR-CA patients revealed an area under the curve of 0.986 and 0.943, respectively. A H/M ratio of > 1.41 identified ATTR-CA patients with a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100, 93.3, 93.3, and 100%, respectively. Conversely, an H/CL ratio of > 1.3 identified ATTR-CA patients with 100% sensitivity, 40.0% specificity, 62.5% PPV, and 100% NPV.<br /><b>Conclusion</b><br />The H/M ratio obtained at 3 hours post-injection has the potential to be a novel indicator for ATTR-CA.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 22 Dec 2022; epub ahead of print</small></div>

<div><h4>A highly predictive cardiac positron emission tomography (PET) risk score for 90-day and one-year major adverse cardiac events and revascularization.</h4><i>McCubrey RO, Mason SM, Le VT, Bride DL, ... Min DB, Knight S</i><br /><b>Background</b><br />With the increase in cardiac PET/CT availability and utilization, the development of a PET/CT-based major adverse cardiovascular events, including death, myocardial infarction (MI), and revascularization (MACE-Revasc) risk assessment score is needed. Here we develop a highly predictive PET/CT-based risk score for 90-day and one-year MACE-Revasc.<br /><b>Methods and results</b><br />11,552 patients had a PET/CT from 2015 to 2017 and were studied for the training and development set. PET/CT from 2018 was used to validate the derived scores (n = 5049). Patients were on average 65 years old, half were male, and a quarter had a prior MI or revascularization. Baseline characteristics and PET/CT results were used to derive the MACE-Revasc risk models, resulting in models with 5 and 8 weighted factors. The PET/CT 90-day MACE-Revasc risk score trended toward outperforming ischemic burden alone [P = .07 with an area under the curve (AUC) 0.85 vs 0.83]. The PET/CT one-year MACE-Revasc score was better than the use of ischemic burden alone (P < .0001, AUC 0.80 vs 0.76). Both PET/CT MACE-Revasc risk scores outperformed risk prediction by cardiologists.<br /><b>Conclusion</b><br />The derived PET/CT 90-day and one-year MACE-Revasc risk scores were highly predictive and outperformed ischemic burden and cardiologist assessment. These scores are easy to calculate, lending to straightforward clinical implementation and should be further tested for clinical usefulness.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 19 Dec 2022; epub ahead of print</small></div>

<div><h4>Cardiac DPD-uptake time dependency in ATTR patients verified by quantitative SPECT/CT and semiquantitative planar parameters.</h4><i>Wollenweber T, Rettl R, Kretschmer-Chott E, Rasul S, ... Hacker M, Traub-Weidinger T</i><br /><b>Background</b><br />Bone scintigraphy plays an important role in the diagnosis of cardiac Transthyretin-Related Amyloidosis (ATTR). The mechanism of myocardial tracer accumulation and its dependence over time are not fully understood. Recently, a scintigraphic quantification of the cardiac amyloid deposition has been discussed. Nevertheless, little is known regarding the right time of quantitative imaging.<br /><b>Methods</b><br />The geometrical mean of decay corrected total counts over the heart and the heart/whole-body ratio (H/WB) were evaluated in 23 patients undergoing DPD-bone scan with planar whole-body images 1 and 3 hours post injection (p.i.). Myocardial standard uptake values (SUV)peak were assessed in another 15 patients with quantitative SPECT/CT imaging 1 hours and 3 hours p.i..<br /><b>Results</b><br />Total counts over the heart (1 hours p.i.: 81,676 cts, range 69,887 to 93,091 cts and 3 hours p.i.: 64,819 cts, range 52,048 to 86,123 cts, P = .0005) and H/WB ratio (1 hours p.i.:0.076 ± 0.020 and 3 hours p.i. 0.070 ± 0.022; P = .0003) were significantly increased 1 hours p.i.. Furthermore median myocardial SUVpeak (1 hours p.i.:12.2, range 9.6 to 18.9 and 3 hours p.i.: 9.6, range 8.2 to 15.0, P = 0.0012) was also significantly higher after 1 hours p.i. compared to 3 hours p.i..<br /><b>Conclusion</b><br />Cardiac DPD activity and myocardial SUVpeak are time-dependent, which should be considered when using quantitative bone scintigraphy in ATTR patients.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 13 Dec 2022; epub ahead of print</small></div>

<div><h4>Left-ventricular volumes and ejection fraction from cardiac ECG-gated O-water positron emission tomography compared to cardiac magnetic resonance imaging using simultaneous hybrid PET/MR.</h4><i>Nordström J, Kvernby S, Kero T, Sörensen J, Harms HJ, Lubberink M</i><br /><b>Background</b><br /><sup>15</sup>O-water PET is the gold standard for noninvasive quantification of myocardial blood flow. In addition to evaluation of ischemia, the assessment of cardiac function and remodeling is important in all cardiac diseases. However, since <sup>15</sup>O-water is freely diffusible and standard uptake images show little contrast between the myocardium and blood pool, the assessment of left-ventricular (LV) volumes and ejection fraction (EF) is challenging. Therefore, the aim of the present study was to investigate the feasibility of calculating LV volumes and EF from first-pass analysis of <sup>15</sup>O-water PET, by comparison with cardiac magnetic resonance imaging (CMR) using a hybrid PET/MR scanner.<br /><b>Methods</b><br />Twenty-four patients with known or suspected CAD underwent a simultaneous ECG-gated cardiac PET/MR scan. The <sup>15</sup>O-water first-pass images (0-50 seconds) were analyzed using the CarPET software and the CMR images were analyzed using the software Segment, for LV volumes and EF calculations. The LV volumes and EF were compared using correlation and Bland-Altman analysis. In addition, inter- and intra-observer variability of LV volumes and EF were assessed for both modalities.<br /><b>Results</b><br />The correlation between PET and CMR was strong for volumes (r > 0.84) and moderate for EF (r = 0.52), where the moderate correlation for EF was partly due to the small range of EF values. Agreement was high for all parameters, with a slight overestimation of PET values for end-diastolic volume but with no significant mean bias for other parameters. Inter- and intra-observer agreement of volumes was high and comparable between PET and CMR. For EF, inter-observer agreement was higher for PET and intra-observer agreement was higher for CMR.<br /><b>Conclusion</b><br />LV volumes and EF can be calculated by first-pass analysis of a <sup>15</sup>O-water PET scan with high accuracy and comparable precision as with CMR.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 08 Dec 2022; epub ahead of print</small></div>

<div><h4>Dose-consistent dynamic SPECT.</h4><i>Krakovich A, Gelbart E, Moalem I, Naimushin A, ... Scheinowitz M, Goldkorn R</i><br /><b>Background</b><br />Coronary flow reserve (CFR) values measured by dynamic SPECT systems are typically consistent with other modalities (e.g., PET). However, large discrepancies are often observed for individual patients. Positioning of the region-of-interest (ROI), representing the arterial input function (AIF) could explain some of these discrepancies. We explored the possibility of positioning the ROI in a manner that evaluates its consistency with patient-based injected radiotracer doses.<br /><b>Methods</b><br />Dose-consistent dynamic SPECT methodology was introduced, and its application was demonstrated in a twenty-patient clinical study. The effect of various ROI positions was investigated and comparison to myocardial perfusion imaging was performed.<br /><b>Results</b><br />Mean AIF ratios were consistent with the injected dose ratios for all examined ROI positions. Good agreement (> 80%) between total perfusion deficit and CFR was found in the detection of obstructive CAD patients for all ROIs considered. However, for individual patients, significant dependence on ROI position was observed (altering CFR by typically 30%). The proposed methodology\'s uncertainty was evaluated (~ 7%) and found to be smaller than the variability due to choice of ROI position.<br /><b>Conclusion</b><br />Dose-consistent dynamic SPECT may contribute to evaluating uncertainty of CFR measurements and may potentially decrease uncertainty by allowing improved ROI positioning for individual patients.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 08 Dec 2022; epub ahead of print</small></div>

<div><h4>Imaging of cardiac sympathetic dysfunction with 18F-FDOPA PET/CT in patients with heart failure: a pilot study.</h4><i>Thanigainathan T, Sharma A, Patel C, Seth S, ... Kumar P, Bal CS</i><br /><b>Background</b><br />Routine use of cardiac sympathetic imaging in HF has been limited by the lower availability/sensitivity of radiotracers. This study was aimed to assess the feasibility of 18F-FDOPA (commonly available PET-radiotracer) in assessment of cardiac autonomic dysfunction.<br /><b>Methods</b><br />Twenty-four controls (46.5 ± 11.1 years, 16men) and 24 patients (43.5 ± 11.0 years, 18men) with diagnosed HF (Framingham-Criteria) underwent cardiac-PET/CT. Region(s) Of Interest were drawn over entire left ventricular myocardium (LV), individual walls, and mediastinum (M). Coefficient of Variation (CV) was calculated from individual wall counts.<br /><b>Results</b><br />HF patients had significantly lower myocardial 18F-FDOPA uptake (P < .001, independent t test) than controls [32.4% ± 9.5% global reduction; highest in apex (39.9% ± 7.0%)]. A cut-off of LV/M ≤ 1.68 could differentiate patients from controls with sensitivity and specificity of 100% and 95.8%, respectively. LV/M correlated positively with EF (Pearson coefficient = 0.460, P .031). During follow-up, 3 patients were lost to follow-up, 4 died (survival-20.5 ± 4 months), 2 worsened, and 15 remained stable/showed mild improvement. Patients who worsened/died during follow-up had higher CV than those with stable/improving symptoms [0.16 ± 0.05 vs 0.11 ± 0.05, P value .069 (independent t test); Cox regression P = .084].<br /><b>Conclusion</b><br />Myocardial 18F-FDOPA uptake in patients with HF is significantly reduced. Higher reduction is seen in those with lower EF. CV, a maker of regional heterogeneity, is a potential prognostic marker.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 06 Dec 2022; epub ahead of print</small></div>

<div><h4>Automated dynamic motion correction improves repeatability and reproducibility of myocardial blood flow quantification with rubidium-82 PET imaging.</h4><i>Choueiry J, Mistry NP, Beanlands RSB, deKemp RA</i><br /><b>Background</b><br />Patient motion reduces the accuracy of PET myocardial blood flow (MBF) measurements. This study evaluated the effect of automatic motion correction on test-retest repeatability and inter-observer variability in a clinically relevant population.<br /><b>Methods</b><br />Patients with known or suspected CAD underwent repeat rest <sup>82</sup>Rb PET scans within minutes as part of their scheduled rest-stress perfusion study. Two trained observers evaluated the presence of heart motion in each scan. Global LV and per-vessel MBF were computed from the dynamic rest images before and after automatic motion correction. Test-retest and inter-observer variability were assessed using intra-class correlation and Bland-Altman analysis.<br /><b>Results</b><br />140 pairs of test-retest scans were included, with visual motion noted in 18%. Motion correction decreased the global MBF values by 3.5% (0.80 ± 0.24 vs 0.82 ± 0.25 mL⋅min<sup>-1</sup>⋅g<sup>-1</sup>; P < 0.001) suggesting that the blood input function was underestimated in cases with patient motion. Test-retest repeatability of global MBF improved by 9.7% (0.25 vs 0.28 mL⋅min<sup>-1</sup>⋅g<sup>-1</sup>; P < 0.001) and inter-observer repeatability was improved by 7.1% (0.073 vs 0.079 mL⋅min<sup>-1</sup>⋅g<sup>-1</sup>; P = 0.012). There was a marked impact on both test-retest repeatability as well as inter-observer repeatability in the LCX territory, with improvements of 16.5% (0.30 vs 0.36 mL⋅min<sup>-1</sup>⋅g<sup>-1</sup>; P < 0.0000) and 18.4% (0.13 vs 0.16 mL⋅min<sup>-1</sup>⋅g<sup>-1</sup>; P < 0.001), respectively.<br /><b>Conclusion</b><br />Automatic motion correction improved test-retest repeatability and reduced differences between observers.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 02 Dec 2022; epub ahead of print</small></div>

<div><h4>Regional myocardial sympathetic denervation precedes the development of left ventricular systolic dysfunction in chronic Chagas\' cardiomyopathy.</h4><i>Gadioli LP, Miranda CH, Marin-Neto JA, Volpe GJ, ... de Figueiredo AB, Simões MV</i><br /><b>Background</b><br />Regional myocardial sympathetic denervation is a conspicuous and early disorder in patients with chronic Chagas\' cardiomyopathy (CCC), potentially associated to the progression of myocardial dysfunction OBJECTIVE: To evaluate in a longitudinal study the association between the presence and the progression of regional myocardial sympathetic denervation with the deterioration of global and segmental left ventricular dysfunction in CCC.<br /><b>Methods</b><br />18 patients with CCC were submitted at initial evaluation and after 5.5 years to rest myocardial scintigraphy with <sup>123</sup>Iodo-metaiodobenzylguanidine and <sup>99m</sup>Tc-sestamibi and to two-dimensional echocardiography to assess myocardial sympathetic denervation, extent of fibrosis, and the left ventricular ejection fraction (LVEF) and wall motion abnormalities.<br /><b>Results</b><br />In the follow-up evaluation, compared to the initial one, we observed a significant decrease in LVEF (56 ± 11 to 49% ± 12; P = .01) and increased summed defects scores in the myocardial innervation scintigraphy (15 ± 10 to 20 ± 9; P < .01). The presence of regional myocardial sympathetic denervation in ventricular regions of viable non-fibrotic myocardium presented an odds ratio of 4.25 for the development of new wall motion abnormalities (P = .001).<br /><b>Conclusion</b><br />Regional and global myocardial sympathetic denervation is a progressive derangement in CCC. In addition, the regional denervation is topographically associated with areas of future development of regional systolic dysfunction in patients with CCC.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 01 Dec 2022; 29:3166-3176</small></div>

<div><h4>F-18 meta-fluorobenzylguanidine PET imaging of myocardial sympathetic innervation.</h4><i>Grkovski M, Zanzonico PB, Modak S, Humm JL, Narula J, Pandit-Taskar N</i><br /><b>Background</b><br />I-123 meta-iodobenzylguanidine (MIBG) imaging has long been employed to noninvasively assess the integrity of human norepinephrine transporter-1 and, hence, myocardial sympathetic innervation. Positron-emitting F-18 meta-fluorobenzylguanidine (MFBG) has recently been developed for potentially superior quantitative characterization. We assessed the feasibility of MFBG imaging of myocardial sympathetic innervation.<br /><b>Methods</b><br />16 patients were imaged with MFBG PET (30-minute dynamic imaging of chest, followed by 3 whole-body acquisitions between 30 minutes and 4-hour post-injection). Blood kinetics were assessed from multiple samples. Pharmacokinetic modeling with reversible 1- and 2-compartment models was performed. Kinetic rate constants were re-calculated from truncated datasets. All patients underwent concurrent MIBG SPECT.<br /><b>Results</b><br />MFBG myocardial uptake was rapid and sustained; the mean standardized uptake value (SUV (mean ± standard deviation)) was 5.1 ± 2.2 and 3.4 ± 1.9 at 1 hour and 3-4-hour post-injection, respectively. The mean K<sub>1</sub> and distribution volume (V<sub>T</sub>) were 1.1 ± 0.6 mL/min/g and 34 ± 22 mL/cm<sup>3</sup>, respectively. Both were reproducible when re-calculated from truncated 1-hour datasets (Intraclass Correlation Coefficient of 0.99 and 0.91, respectively). Spearman\'s ϱ = 0.86 between MFBG SUV and V<sub>T</sub> and 0.80 between MFBG PET-derived V<sub>T</sub> and MIBG SPECT-derived heart-to-mediastinum activity concentration ratio.<br /><b>Conclusion</b><br />MFBG is a promising PET radiotracer for the assessment of myocardial sympathetic innervation.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 01 Dec 2022; 29:3179-3188</small></div>

<div><h4>Metabolic activity of the left and right atria are differentially altered in patients with atrial fibrillation and LV dysfunction.</h4><i>Santi ND, Wu KY, Redpath CJ, Nery PB, ... deKemp RA, Beanlands RSB</i><br /><b>Background</b><br />Alterations in atrial metabolism may play a role in the perpetuation of atrial fibrillation (AF). This study sought to compare <sup>18</sup>F-fluorodeoxyglucose (FDG) uptake on PET, in patients with LV dysfunction versus those without AF.<br /><b>Methods</b><br />Seventy-two patients who underwent myocardial viability assessment were evaluated. AF patients (36) had persistent or permanent AF based on history and ECG. Patients without AF (36) were matched to AF patients based on sex, diabetes, age, and LVEF. Maximum and mean FDG Standard Uptake Values (SUV) in the left atrial (LA) wall and right atrial (RA) wall were measured. Tissue-to-blood ratios (TBR) were calculated as atrial wall to blood-pool activity. Atrial volumes were measured by echocardiography.<br /><b>Results</b><br />Maximum and mean FDG SUV and TBRs were significantly increased in the RA (but not the LA) of patients with AF compared to those without (P < 0.01). When accounting for changes in atrial volume, the presence of AF remained a significant predictor of higher RA<sub>MAX</sub>, but not RA<sub>MEAN</sub> FDG uptake.<br /><b>Conclusion</b><br />In patients with LV dysfunction from ischemic cardiomyopathy, LA and RA glucose metabolism are differentially altered in those with persistent atrial fibrillation. Further investigations should elucidate the temporal relationship between AF and glucose metabolic changes, as a potential target for therapy.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 01 Dec 2022; 29:2824-2836</small></div>

<div><h4>Comparison of cardiac magnetic resonance imaging and fluorodeoxyglucose positron emission tomography in the assessment of cardiac sarcoidosis: Meta-analysis and systematic review.</h4><i>Adhaduk M, Paudel B, Khalid MU, Ashwath M, Mansour S, Liu K</i><br /><b>Aim</b><br />Fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) and cardiac magnetic resonance (CMR) are frequently used advanced cardiac imaging to diagnose cardiac sarcoidosis (CS). We conducted a meta-analysis and systematic review to compare diagnostic parameters of FDG-PET and CMR in the diagnosis of cardiac sarcoidosis (CS).<br /><b>Methods</b><br />We searched PubMed, EMBASE, and Scopus databases from their inception to 9/30/2021 with search terms \"cardiac sarcoidosis\" AND \"cardiac magnetic resonance imaging\" AND \"positronemission tomography\". We extracted patient characteristics, results of the FDG-PET and CMR, and adverse outcomes from the included studies. Adverse outcomes served as a reference standard for the evaluation of FDG-PET and CMR.<br /><b>Results</b><br />We included 4 studies in the meta-analysis which provided adverse outcomes and all patients underwent FDG-PET and CMR. There were 237 patients, 60.3% male, and ages ranged from 50-53 years. There were 45 events in 237 patients from four studies included in the meta-analyses. The pooled sensitivity (95% confidence interval-CI) and specificity (CI) of CMR in predicting an adverse event were 0.94 (0.79-0.98) and 0.49 (0.40-0.59), respectively. The pooled sensitivity (CI) and specificity (CI) of FDG-PET in predicting an adverse event were 0.51 (0.26-0.75) and 0.60 (0.35-0.81), respectively.<br /><b>Conclusion</b><br />CMR was more sensitive but less specific than FDG-PET in predicting adverse events; however, the study population and definition of a positive test need to be considered while interpreting the results.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 28 Nov 2022; epub ahead of print</small></div>

<div><h4>Coronary vasculopathy due to moyamoya disease.</h4><i>Kaur S, Parikh P, Khatri J, Jaber W</i><br /><AbstractText>Moyamoya disease is a rare disorder associated with progressive intracranial arterial stenosis with fragile, small collateralization that gives an angiographic appearance of a puff of smoker or, in Japanese, \"moya-moya\". We report a case of coronary artery ostial occlusive disease as an extracranial manifestation of Moyamoya. In the case, we demonstrate that thigh risk features of cardiac positron emission tomography (PET) that ultimately lead to the diagnosis of coronary artery occlusion.</AbstractText><br /><br />© 2022. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.<br /><br /><small>J Nucl Cardiol: 28 Nov 2022; epub ahead of print</small></div>

<div><h4>Semiquantitative evaluation of Ga-DOTANOC uptake in the normal myocardium: establishment of reference values.</h4><i>Kaushik P, Patel C, Chandra KB, Kumar S, ... Ojha V, Bal C</i><br /><b>Background</b><br />To ascertain presence of physiological uptake and derive standardized uptake values (SUV) of <sup>68</sup>Ga-DOTANOC in normal myocardium and establish reference values.<br /><b>Methods and results</b><br />Dedicated cardiac <sup>68</sup>Ga-DOTANOC PET/CT studies of patients referred for evaluation of cardiac sarcoidosis (CS) or myocarditis and found to be normal on visual assessment and on cardiac MRI were analyzed semiquantitatively. The studies were acquired 45-60 minutes after intravenous injection of 111-185 MBq of <sup>68</sup>Ga-DOTANOC. Myocardial SUV<sub>max</sub> normalized to lean body mass (SUV<sub>max_</sub>lbm) values for septum, anterior wall, proximal lateral wall, distal lateral wall, inferior wall, and apical region were 1.12 ± .39, 1.09 ± .42, 1.26 ± .49, 1.16 ± .40, 1.23 ± .39, and 1.05 ± .40, respectively. Myocardial SUV<sub>max_</sub>lbm-to-blood pool SUV<sub>mean</sub>_lbm ratios were calculated for each region and 95th percentile values of these ratios were considered the upper limit of normal. 95th percentile values of myocardial SUV<sub>max_</sub>lbm-to-blood pool SUV<sub>mean</sub>_lbm ratio for the corresponding regions were 1.70, 1.70, 2.00 1.95, 2.05, and 1.70, respectively.<br /><b>Conclusion</b><br />There can be physiological uptake of <sup>68</sup>Ga-DOTANOC in normal myocardium and the reference values of semiquantitative parameters established in this study may be employed as a corroborative tool for visual assessment in patients undergoing <sup>68</sup>Ga-DOTANOC PET/CT for suspected CS or myocarditis.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 23 Nov 2022; epub ahead of print</small></div>

<div><h4>Beta-blockers and mechanical dyssynchrony in heart failure assessed by radionuclide ventriculography.</h4><i>Jones KA, Paterson CA, Ray S, Motherwell DW, ... Martin W, Goodfield NER</i><br /><b>Background</b><br />Radionuclide ventriculography (RNVG) can be used to quantify mechanical dyssynchrony and may be a valuable adjunct in the assessment of heart failure with reduced ejection fraction (HFrEF). The study aims to investigate the effect of beta-blockers on mechanical dyssynchrony using novel RNVG phase parameters.<br /><b>Methods</b><br />A retrospective study was carried out in a group of 98 patients with HFrEF. LVEF and dyssynchrony were assessed pre and post beta-blockade. Dyssynchrony was assessed using synchrony, entropy, phase standard deviation, approximate entropy, and sample entropy from planar RNVG phase images. Subgroups split by ischemic etiology were also investigated.<br /><b>Results</b><br />An improvement in dyssynchrony and LVEF was measured six months post beta-blockade for both ischemic and non-ischemic groups.<br /><b>Conclusions</b><br />A significant improvement in dyssynchrony and LVEF was measured post beta-blockade using novel measures of dyssynchrony.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 23 Nov 2022; epub ahead of print</small></div>

<div><h4>Incorporating coronary artery calcium scoring in the prediction of obstructive coronary artery disease with myocardial ischemia: a study with sequential use of coronary computed tomography angiography and positron emission tomography imaging.</h4><i>van den Hoogen IJ, Wang X, Butcher SC, Maaniitty T, ... Knuuti J, Bax JJ</i><br /><b>Background</b><br />Additional strategies are needed to refine the referral for diagnostic testing of symptomatic patients with suspected coronary artery disease (CAD). We aimed to compare various models to predict hemodynamically obstructive CAD.<br /><b>Methods and results</b><br />Symptomatic patients with suspected CAD who underwent coronary artery calcium scoring (CACS) and sequential coronary computed tomography angiography (CCTA) and [<sup>15</sup>O]H<sub>2</sub>O positron emission tomography (PET) myocardial perfusion imaging were analyzed. Obstructive CAD was defined as a suspected coronary artery stenosis on CCTA with myocardial ischemia on PET (absolute stress myocardial perfusion ≤ 2.4 mL/g/min in ≥ 1 segment). Three models were developed to predict obstructive CAD-induced myocardial ischemia using logistic regression analysis: (1) basic model: including age, sex and cardiac symptoms, (2) risk factor model: adding number of risk factors to the basic model, and (3) CACS model: adding CACS to the risk factor model. Model performance was evaluated using discriminatory ability with area under the receiver-operating characteristic curves (AUC). A total of 647 patients (mean age 62 ± 9 years, 45% men) underwent CACS and sequential CCTA and PET myocardial perfusion imaging. Obstructive CAD with myocardial ischemia on PET was present in 151 (23%) patients. CACS was independently associated with myocardial ischemia (P < .001). AUC for the discrimination of ischemia for the CACS model was superior over the basic model and risk factor model (P < .001).<br /><b>Conclusions</b><br />Adding CACS to the model including age, sex, cardiac symptoms and number of risk factors increases the accuracy to predict obstructive CAD with myocardial ischemia on PET in symptomatic patients with suspected CAD.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 15 Nov 2022; epub ahead of print</small></div>

<div><h4>Prediction of outcome by Rb PET/CT in patients with ischemia and nonobstructive coronary arteries.</h4><i>Zampella E, Mannarino T, D\'Antonio A, Assante R, ... Cuocolo A, Acampa W</i><br /><b>Background</b><br />The purpose of this study was to assess the prognostic value of cardiac <sup>82</sup>Rb positron emission tomography (PET)/computed tomography (CT) imaging in patients with myocardial ischemia of nonobstructive coronary arteries (INOCA).<br /><b>Methods</b><br />We retrospectively evaluated 311 INOCA patients who underwent rest stress <sup>82</sup>Rb PET/CT. Cardiac end points were cardiac death, myocardial infarction, or late coronary revascularization. A parametric survival model was also used to identify how the variables influenced time to event.<br /><b>Results</b><br />During a median follow-up of 37 months (range 6-108), 23 (7%) cardiac events occurred. In patients with events total perfusion defect (TPD) was higher and myocardial flow reserve (MFR) lower compared to those without events (both P < .001). At multivariable Cox analysis, increased TPD (i.e., ≥ 5%) and reduced MFR (i.e., < 2) were predictors of events (both P < .001). At Weibull survival analysis, the highest probability of cardiac events and risk acceleration were observed in patients with both increased TPD and reduced MFR. Annualized event rate was higher in patients with reduced MFR compared to those with preserved MFR (P < .001).<br /><b>Conclusion</b><br />In patients with INOCA, the combined evaluation of myocardial perfusion and coronary vascular function by <sup>82</sup>Rb PET/CT is able to identify those at higher risk of cardiac events.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 09 Nov 2022; epub ahead of print</small></div>

<div><h4>Impact of disposable syringes type choice on myocardial perfusion imaging procedures with [Tc]Tc-tetrofosmin.</h4><i>Ladriere T, Desmonts C, Zimmermann PA, Peyronnet D, Agostini D, Vigne J</i><br /><b>Background</b><br />Residual activity in dispensing syringes is a problem that has been sporadically reported with various radiopharmaceuticals. Studies with [<sup>99m</sup>Tc]Tc-tetrofosmin are non-consistent so far. The aim was to quantify the residual activity of [<sup>99m</sup>Tc]Tc-tetrofosmin in different syringes in a clinical setting and to assess its impact on the clinical imaging procedure.<br /><b>Methods</b><br />The residual activity of [<sup>99m</sup>Tc]Tc-tetrofosmin was measured in 3 types of syringes: 3-part lubricated and non-lubricated syringes and 2-part syringe (n ≥ 30 for each syringe). The residual activity was located and quantified using a CzT SPECT camera and radio-counting then was correlated with different clinical parameters and processed by multiple linear regression analysis.<br /><b>Results</b><br />Residual activity was different in all syringe types but lubricated syringes showed significantly higher levels with a mean ± SD of 26.12 ± 10.21% (P < .001). For these syringes, the residual activity was mainly located on the lubricated body. They also have a positive and significant impact on the standardized counting duration of patients\' acquisitions.<br /><b>Conclusion</b><br />Lubricated syringes with high residual activity should be avoided as they increase the risk of prolonging patient acquisition time and potentially increasing the risk of poor image quality.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 09 Nov 2022; epub ahead of print</small></div>

<div><h4>Tc-PYP SPECT and SPECT/CT quantitation for diagnosing cardiac transthyretin amyloidosis.</h4><i>Nichols KJ, Yoon SY, Van Tosh A, Palestro CJ</i><br /><b>Background</b><br />We investigated quantitative <sup>99m</sup>Tc-pyrophosphate (PYP) SPECT/CT reproducibility and accuracy for diagnosing cardiac transthyretin amyloidosis (ATTR), and whether SPECT/CT improved visual and quantitative results compared to SPECT-only.<br /><b>Methods</b><br />Data were reviewed for 318 patients with suspected ATTR who underwent PYP SPECT/CT. Myocardial-to-blood pool count (MBP) ratios were computed and repeated independently > 1 month later. A physician independently scored LV myocardial-to-rib uptake on SPECT/CT as: 0 (negative), 1 < rib (equivocal), 2 = rib (positive) or 3 > rib (positive), and the image quality as: 1 (poor), 2 (adequate), and 3 (good). SPECT-only MBP ratios and visual scores were assessed separately for a subgroup of the first sequential 191 patients.<br /><b>Results</b><br />25% of patients had positive myocardial uptake (myocardial-to-rib uptake score of ≥ 2). SPECT/CT MBP ratios were reproducible (1.35 ± .68 vs 1.33 ± .74, p = .09) and corresponded with visual scores ≥ 2 (ROC AUC = 99 ± 1%) more accurately than SPECT-only MBPs (93 ± 3%, p = .02). SPECT/CT image quality was better than that of SPECT-only (2.7 ± .5 vs 2.1 ± .5, p < .0001) with fewer equivocal results (2.6% vs 22.5%, p < .0001).<br /><b>Conclusion</b><br />SPECT/CT produces MBP ratios that are reproducible and accurately identify a positive scan, with better image quality and fewer equivocal cases than SPECT-only.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 09 Nov 2022; epub ahead of print</small></div>

<div><h4>Diagnosis, performance and added value of assessing ventricular dyssynchrony by phase analysis in patients with three-vessel disease: A single-center cross-sectional study in Mexico.</h4><i>Garcia-Cardenas M, Espejel-Guzman A, Antonio-Villa NE, Michel-Vasquez A, ... Alexanderson-Rosas E, Espinola-Zavaleta N</i><br /><b>Background</b><br />Three-vessel disease (3VD) is a cardiovascular disorder that affects the three main coronary arteries. Gated myocardial perfusion SPECT (GMPS) evaluates ventricular function, synchrony, and myocardial perfusion. However, the diagnostic performance of GMPS parameters to assess 3VD has not been fully explored.<br /><b>Aims</b><br />To assess the univariate performance capacity of GMPS parameters, and to evaluate whether phase parameters could provide additional predictive value for the detection of patients with 3VD compared to control subjects.<br /><b>Methods</b><br />We designed paired retrospective samples of GMPS images of patients with 3VD (stenosis > 70% of left anterior descending, right coronary, and circumflex coronary arteries) and without 3VD. A GMPS in rest-stress protocol was performed using 99mTc-Sestamibi and thallium and analyzed with the 3D method. Area under the receiver-operating characteristic curves (AUROC), decision curve analyses and diagnostic test performance were obtained for univariable analyses and stepwise binomial logistic regression for multivariable performance.<br /><b>Results</b><br />474 Patients were included: 237 with 3VD (84% males, mean age 61.7 ± 9.9 years) and 237 with normal GMPS (51% women, mean age 63.8 ± 10.6 years). The highest AUROC for perfusion parameters were recorded for SSS, SRS and TID. For dyssynchrony parameters, both entropy and bandwidth in rest and stress phases displayed the highest AUROC and diagnostic capacity to detect 3VD. A multivariate model with SRS ≥ 4, SDS ≥ 2, TID > 1.19 and sBW ≥ 48° displayed the highest diagnostic capacity (0.923 [95% CI 0.897-0.923]) to detect 3VD.<br /><b>Conclusion</b><br />Perfusion and dyssynchrony were the parameters which were most able to discriminate patients with 3VD from those who did not have CAD.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 08 Nov 2022; epub ahead of print</small></div>

<div><h4>F-FDG/PET-CT imaging findings after sternotomy.</h4><i>Blomjous MSH, Mulders TA, Wahadat AR, Tanis W, ... Roos-Hesselink JW, Budde RPJ</i><br /><b>Background</b><br />The clinical diagnosis of deep sternal wound infection (DSWI) is supported by imaging findings including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (<sup>18</sup>F-FDG-PET/CT). To avoid misinterpretation due to normal post-surgery inflammation we assessed normal imaging findings in non-infected patients after sternotomy.<br /><b>Methods</b><br />This is a prospective cohort study including non-infectious patients with sternotomy. All patients underwent <sup>18</sup>F-FDG-PET/CT at either 5 weeks (group 1), 12 weeks (group 2) or 52 weeks (group 3) post-surgery. <sup>18</sup>F-FDG uptake was scored visually in five categories and assessed quantitatively.<br /><b>Results</b><br />A total of 44 patients were included. Sternal mean SUVmax was 7.34 (± 1.86), 5.22 (± 2.55) and 3.20 (± 1.80) in group 1, 2 and 3, respectively (p < 0.01). Sternal mean SUVmean was 3.84 (± 1.00), 2.69 (± 1.32) and 1.71 (± 0.98) in group 1, 2 and 3 (p < 0.01). All patients in group 1 had elevated uptake whereas group 2 and 3 showed 2/15 (13%) and 11/20 (55%) patients respectively with no elevated uptake. Group 3 still showed an elevated uptake pattern in in 9/20 (45%) and in 3/9 (33%) with a high-grade diffuse uptake pattern.<br /><b>Conclusion</b><br />This study shows significant lower sternal <sup>18</sup>F-FDG at 55 weeks compared to 5 weeks post-sternotomy however elevated uptake patterns may persist.<br /><br />© 2022. The Author(s).<br /><br /><small>J Nucl Cardiol: 08 Nov 2022; epub ahead of print</small></div>

<div><h4>Quantification of intramyocardial blood volume using Tc-RBC SPECT/CT: a pilot human study.</h4><i>Yousefi H, Shi L, Soufer A, Tsatkin V, ... Sinusas A, Liu C</i><br /><b>Background</b><br />Quantification of intramyocardial blood volume (IMBV), the fraction of myocardium that is occupied by blood, is a promising Index to measure microcirculatory functions. In previous large animal SPECT/CT studies injected with <sup>99m</sup>Tc-labeled Red Blood Cell (RBC) and validated by ex vivo microCT, we have demonstrated that accurate IMBV can be measured. In this study, we report the data processing methods and results of the first-in-human pilot study.<br /><b>Methods</b><br />Data from three subjects have been included to date. Each subject underwent rest and adenosine-induced stress <sup>99m</sup>Tc-RBC SPECT/CT on a dedicated cardiac system with both non-contrast and contrast-enhanced CT acquired. Corrections of attenuation (AC) and scatter (SC), respiratory and cardiac gating, and partial volume correction (PVC) were applied. We also performed automatic segmentation and registration approach based on the blood pool topology in both SPECT and CT images.<br /><b>Results</b><br />The quantified IMBV across all subjects under resting conditions were 35.0% ± 3.3% for the end-diastolic phase and 24.1% ± 2.7% for the end-systolic phase. The cycle-dependent change in IMBV (ΔIMBV) between diastolic and systolic phases was 31.5% ± 3.0%. Under stress, IMBV were 40.6% ± 4.2% for the end-diastolic phase and 26.5% ± 2.8% for the end-systolic phase, and ΔIMBV was 34.7% ± 7.4%.<br /><b>Conclusions</b><br />It is feasible to quantify IMBV in resting and stress conditions in human studies using SPECT/CT with <sup>99m</sup>Tc-RBC.<br /><br />© 2022. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.<br /><br /><small>J Nucl Cardiol: 01 Nov 2022; epub ahead of print</small></div>