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This study aimed to evaluate the diagnostic performance of combined dynamic stress CT myocardial perfusion imaging (CTP) and coronary CT angiography (CTA) alongside CT-derived fractional flow reserve (CT-FFR) in detecting hemodynamically significant coronary artery disease (CAD). A total of 33 patients (86 vessels) who underwent coronary CTA, dynamic stress CTP, and coronary angiography were included. Vessels exhibiting 30-90% stenosis were subjected to FFR analysis based on coronary angiography (Angio-FFR). Hemodynamic significance, determined by Angio-FFR ≤ 0.80, and imaging findings were evaluated. The evaluation involved a comparison between the combined use of coronary CTA, CTP and CT-FFR, versus the sole use of coronary CTA. Out of 86 coronary vessels, 17 (19.8%) exhibited hemodynamically significant stenosis. The sensitivity, specificity, and accuracy of coronary CTA for detecting ischemia were 94.12%, 34.78%, and 46.51%, respectively. Adding CTP to CTA improved specificity to 88.41%, and accuracy to 87.21%, respectively. The area under the curve (AUC) for the discrimination of functional significant stenosis was 0.798 when using CTA alone, and for CTA plus CTP, it reached 0.910. Furthermore, the combination of CTA, CTP and CT-FFR, showed accuracy of 88.37%, sensitivity of 88.24% and specificity of 88.41% with the AUC of 0.946. The integration of dynamic CTP with CTA significantly enhances the diagnostic accuracy for identifying patients with hemodynamically significant CAD, compared to the use of CTA alone. This study underscores the value of combining CTP, CT-FFR, and CTA in improving diagnostic precision for CAD. The combination of CTP, CT-FFR and CTA offers a multifaceted assessment for patients with CAD by simultaneously providing anatomical detail, functional analysis, and physiological quantification, which facilitating rapid, accurate, and optimal clinical decision-making and significantly enhances patient management., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Aim: To assess in a phantom and in a clinical study the influence of different reconstruction parameters on quantitative SPECT/CT values in the assessment of cardiac transthyretin amyloidosis (ATTR-CA)., Method: A hybrid SPECT/CT camera with a proprietary software for SPECT/CT-based quantification of myocardial uptake of 99m Tc-DPD was used. Images were reconstructed with 6 different protocols, differing in iterations, subset and Gaussian filter. Quantitative values were tested in phantom and clinical studies across different reconstruction protocols. Values were automatically calculated both as kBq/ml and as maximum, mean and peak standardized uptake value (SUV)., Results: The standard parameters provided by the manufacturer (reconstruction 1) yielded higher accuracy in quantifying, with measuring 97.1% of the expected activity in the phantom. Reconstructions with higher Gaussian filter caused a systematic underestimation of quantified values of 27.2% (p < 0.01). Results were replicated in the clinical study consisting of 155 patients with suspected ATTR-CA, wherein changing the number of iterations and subsets was not associated with a statistically significant difference in quantitative values compared to reconstruction 1, while a higher Gaussian filter caused inaccurate quantification with up to 24% of difference measured., Conclusion: Different reconstruction parameters can impact quantitative values on 99m Tc-DPD SPECT/CT. Therefore, parameters should be maintained consistently across different acquisitions and different centres., Competing Interests: Declarations Competing interests The authors declare no competing interests. Disclosures Robin Schepers has received speaker honoraria from Siemens. Christoph Gräni receives funding from the Swiss National Science foundation, InnoSuisse, CAIM foundation, GAMBIT foundation and Novartis biomedical research foundation, outside of the submitted work. Axel Rominger has received research support and speaker honoraria from Siemens. Federico Caobelli is currently supported by a research grant by Siemens Healthineers and receives speakers Honoraria by Bracco AG and Pfizer AG for matters not related to the present manuscript. All other authors have no competing interests to disclose., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Fractional flow reserve (FFR) has emerged as the invasive gold standard for assessing vessel-specific ischemia. However, FFR measurements are influenced by the hydrostatic effect, which might adversely impact the assessment of ischemia., Aims: This study aimed to investigate the impact of hydrostatic pressure on FFR measurements by correcting for the height and comparing FFR with [ 15 O]H 2 O positron emission tomography (PET)-derived relative flow reserve (RFR)., Methods: The 206 patients were included in this analysis. Patients underwent coronary computed tomography angiography (CCTA), [ 15 O]H 2 O PET, and invasive coronary angiography with routine FFR in every epicardial artery. Height differences between the aortic guiding catheter and distal pressure sensor were quantified on CCTA images. An FFR ≤ 0.80 was considered significant., Results: The study found a reclassification in 7% of the coronary arteries. Notably, 11% of left anterior descending (LAD) arteries were reclassified from hemodynamically significant to nonsignificant. Conversely, 6% of left circumflex (Cx) arteries were reclassified from nonsignificant to significant. After correcting for the hydrostatic pressure effect, the correlation between FFR and PET-derived RFR increased significantly from r = 0.720 to r = 0.786 (p = 0.009). The average magnitude of correction was +0.05 FFR units in the LAD, -0.03 in the Cx, and -0.02 in the right coronary artery., Conclusion: Hydrostatic pressure has a small but clinically relevant influence on FFR measurements obtained with a pressure wire. Correcting for this hydrostatic error significantly enhances the correlation between FFR and PET-derived RFR., (© 2024 The Author(s). Catheterization and Cardiovascular Interventions published by Wiley Periodicals LLC.)

Coronary computed tomography angiography (cCTA) has poor specificity to identify coronary stenosis that limit blood flow to the myocardial tissue. Integration of dynamic CT myocardial perfusion imaging (CT-MPI) can potentially improve the diagnostic accuracy. We propose a method that integrates cCTA and CT-MPI to identify culprit coronary lesions that limit blood flow to the myocardium. Coronary arteries and left ventricle surfaces were segmented from cCTA and registered to CT-MPI. Myocardial blood flow (MBF) was derived from CT-MPI. A ray-casting approach was developed to project volumetric MBF onto the left ventricle surface. MBF volume were divided into coronary-specific territories based on proximity to the nearest coronary artery. MBF and normalized MBF were computed for the entire myocardium and each of the coronary artery. Projection of MBF onto cCTA allowed for direct visualization of perfusion defects. Normalized MBF had higher correlation with ischemic myocardial territory compared to MBF (MBF: R2=0.81 and Index MBF: R2=0.90). There were 18 vessels that showed angiographic disease (stenosis >50%); however, normalized MBF demonstrated only 5 coronary territories to be ischemic. These findings demonstrate that cCTA and CT-MPI can be integrated to visualize myocardial defects and detect culprit coronary arteries responsible for perfusion defects. These methods can allow for non-invasive detection of ischemia-causing coronary lesions and ultimately help guide clinicians to deliver more targeted coronary interventions.

Background: Myocardial perfusion SPECT (MPS) and exercise electrocardiography (Ex-ECG) results are of prognostic importance for short-term follow up duration. However, the value of MPS or Ex-ECG findings for long-term risk assessment is less evident as underlying risk factors for ischemic heart disease (IHD) gain in importance., Objectives: To assess the short- and long-term prognostic value of MPS and Ex-ECG in relation to known risk factors., Methods and Materials: An observational study of 908 patients (age 63 years, 49% male, 45% prior IHD) referred for MPS and Ex-ECG. Follow-up was divided into two periods (short-term: <5 years and long-term: >5 years). Cardiac events were defined as a composite of acute myocardial infarction, unstable angina, unplanned revascularization and cardiovascular death., Results: The composite endpoint occurred in 95 patients (short-term follow up) and in 94 patients (long-term follow up). In multivariable models stress testing had a strong predictive value for short-term follow up (HR for MPS = 2.9, CI = 1.9-4.5, p < 0.001 and HR for Ex-ECG = 2.1, CI 1.3-3.3, p = 0.002), but no predictive value for long-term follow up (HR for MPS = 0.9, CI = 0.5-1.5, p = 0.70 and HR for Ex-ECG = 1.0, CI = 0.6-1.6, p = 0.92). Male sex and prior IHD were significant predictors regardless of follow up duration. Age, diabetes and decreased exercise capacity were risk factors for long-term follow up., Conclusions: The prognostic value of MPS and Ex-ECG results are strong for short-term follow up but diminish over time and do not contribute significantly in multivariable models after 5 years. Long-term prognosis is primarily governed by underlying risk factors and exercise capacity., (© 2024 The Author(s). Clinical Physiology and Functional Imaging published by John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Background: Coronary microvascular function is impaired in patients with obesity, contributing to myocardial dysfunction and heart failure. Bariatric surgery decreases cardiovascular mortality and heart failure, but the mechanisms are unclear., Objectives: The authors studied the impact of bariatric surgery on coronary microvascular function in patients with obesity and its relationship with metabolic syndrome., Methods: Fully automated quantitative perfusion cardiac magnetic resonance and metabolic markers were performed before and 6 months after bariatric surgery., Results: Compared with age- and sex-matched healthy volunteers, 38 patients living with obesity had lower stress myocardial blood flow (MBF) (P = 0.001) and lower myocardial perfusion reserve (P < 0.001). A total of 27 participants underwent paired follow-up 6 months post-surgery. Metabolic abnormalities reduced significantly at follow-up including mean body mass index by 11 ± 3 kg/m 2 (P < 0.001), glycated hemoglobin by 9 mmol/mol (Q1-Q3: 4-19 mmol/mol; P < 0.001), fasting insulin by 142 ± 131 pmol/L (P < 0.001), and hepatic fat fraction by 5.6% (Q1-Q3: 2.6%-15.0%; P < 0.001). Stress MBF increased by 0.28 mL/g/min (Q1-Q3: -0.02 to 0.75 mL/g/min; P = 0.003) and myocardial perfusion reserve by 0.13 (Q1-Q3: -0.25 to 1.10; P = 0.036). The increase in stress MBF was lower in those with preoperative type 2 diabetes mellitus (0.1 mL/g/min [Q1-Q3: -0.09 to 0.46 mL/g/min] vs 0.75 mL/g/min [Q1-Q3: 0.31-1.25 mL/g/min]; P = 0.002). Improvement in stress MBF was associated with reduction in fasting insulin (beta = -0.45 [95% CI: -0.05 to 0.90]; P = 0.03)., Conclusions: Coronary microvascular function is impaired in patients with obesity, but can be improved significantly with bariatric surgery. Improvements in microvascular function are associated with improvements in insulin resistance but are attenuated in those with preoperative type 2 diabetes mellitus., Competing Interests: Funding Support and Author Disclosures Dr Joy has been supported by a British Heart Foundation Clinical Research Training Fellowship (FS/CRTF/21/2469). Dr McGowan was supported by project grants from Guys and St. Thomas’ Charity Grant, Janet James Fund; has undertaken advisory work for Novo Nordisk and Lilly; has performed educational work with Novo Nordisk and Biogen; has an academic grant with Novo Nordisk; and is a shareholder in Reset health. Dr Manisty has been supported by funding with the University Hospitals London NHS Trust National Institute for Health and Care Research Biomedical Research Centre. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024. Published by Elsevier Inc.)

The influence of computed tomography attenuation correction (CTAC) on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) combined with F-18-FDG Positron Emission Tomography/Computed Tomography (PET/CT) metabolic imaging, compared with conventional SPECT MPI, remains to be fully elucidated. To evaluate the impact of CTAC on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT, compared to conventional SPECT MPI. 193 patients underwent CZT SPECT and F-18-FDG PET/CT imaging, while 39 patients underwent conventional SPECT and F-18-FDG PET/CT imaging, with both groups utilizing CT for attenuation correction. The injured myocardium (hibernating and scarring) was quantified using the Q.PET software. After CTAC, both groups showed significant improvements in perfusion of the injured myocardial areas, particularly in the inferior wall (INF). The reduction in perfusion was more notable in the CZT SPECT group than that in the conventional group, particularly in the inferior and lateral walls. Among patients with large cardiac chambers, those undergoing MPI with CZT, with normal weights, or males, hibernating myocardium (HM) and scar post-CTAC reductions were particularly significant in the INF. If HM ≥ 10% is considered an indicator for recommended revascularization, among the 87 patients without prior cardiac bypass, 25 (28.7%) might not require revascularization treatment. Dedicated cardiac CZT SPECT and conventional SPECT MPI combined with F-18-FDG PET/CT significantly influenced the assessment of viable myocardium. The impact of CTAC was more profound in dedicated cardiac CZT SPECT, particularly in the INF region. CTAC significantly enhances the accuracy of viable myocardial assessment and may influence clinical decisions regarding revascularization therapy. Therefore, CTAC should be routinely used in dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT for myocardial viability diagnosis., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Despite tremendous therapeutic advancements, a significant proportion of coronary artery disease patients suffer from refractory angina pectoris, that is, quality-of-life-compromising angina that is non-manageable with established pharmacological and interventional treatment options. Adenoviral vascular endothelial growth factor-D ΔNΔC (AdVEGF-D)-encoding gene therapy (GT) holds promise for the treatment of refractory angina., Methods: ReGenHeart is an investigator-initiated, multicentre, randomised, placebo-controlled and double-blinded phase 2 clinical trial that aims to study the safety and efficacy of intramyocardially administered angiogenic AdVEGF-D GT for refractory angina. Patients will be randomised in a 2:1 ratio and blocks of six to receive either AdVEGF-D or placebo. Primary endpoints are improvements in functional capacity assessed with the 6 min walking test and angina symptoms with Canadian Cardiovascular Society class after 6 month follow-up. Secondary endpoints are improvements in myocardial perfusion assessed with either positron emission tomography or single-photon emission CT after 6 month follow-up and functional capacity and angina symptoms after 12 months. In addition, changes in the quality of life, the use of angina medication and the incidence of major adverse cardiac and cerebrovascular events will be evaluated., Conclusions: The phase 2 ReGenHeart trial will provide knowledge of the safety and efficacy of AdVEGF-D GT to ameliorate symptoms in refractory angina patients, extending and further testing positive results from the preceding phase 1/2a trial., Competing Interests: Competing interests: JEKH received consultancy fees from Novo Nordisk and speaker fees from the BMS-Pfizer alliance. JK received consultancy fees from GE Healthcare and Synektik and speaker fees from GE Healthcare, Bayer, Lundbeck, Boehringer-Ingelheim, Pfizer, Siemens Healthineers and Merck, outside of the submitted work. AS received consultancy fees from Amgen, Astra Zeneca, Boehringer Ingelheim and Pfizer, and speaker fees from Abbott, Astra Zeneca and Bayer. Other authors declare that they have no conflicts of interest., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Thrombus aspiration (TA) is used to decrease large thrombus burden (LTB), but it can cause distal embolization., Objectives: The aim of this study was to investigate the impact of TA failure on defective myocardial perfusion in patients with ST-segment elevation myocardial infarction (STEMI) and LTB., Methods: In total, 812 consecutive patients with STEMI and LTB (thrombus grade ≥3) were enrolled, who underwent manual TA during the primary percutaneous coronary intervention. TA failure was defined as the absence of thrombus retrieval, presence of prestenting thrombus residue, or distal embolization. The final TIMI flow grades and other myocardial perfusion parameters of the failed TA group were matched with those of the successful TA group., Results: The proportion of final TIMI flow grade 3 was lower (74.6% vs 82.2%; P = 0.011) in the failed TA group (n = 279 [34.4%]) than in the successful TA group (n = 533 [65.6%]). The failed TA group also had lower myocardial blush grade, lower ST-segment resolution, and a higher incidence of microvascular obstruction than the successful TA group. TA failure was independently associated with low final TIMI flow grade (risk ratio: 1.525; 95% CI: 1.048-2.218; P = 0.027). Old age, Killip class ≥III, vessel tortuosity, calcification, and a culprit vessel other than the left anterior descending coronary artery were associated with TA failure., Conclusions: TA failure is associated with reduced myocardial perfusion in patients with STEMI and LTB. Advanced age, hemodynamic instability, hostile coronary anatomy such as tortuosity or calcification, and non-left anterior descending coronary artery status might attenuate TA performance. (Gangwon PCI Prospective Registry [GWPCI]; NCT02038127)., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: The objective of this study was to investigate the role of myocardial perfusion imaging (MPI) stress tests using stress cardiac magnetic resonance (sCMR) and single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in non-cardiac surgery (NCS) pre-operatory management., Materials and Methods: This monocentric retrospective study enrolled patients with coronary artery disease or a minimum of two cardiovascular risk factors undergoing intermediate-to-high-risk non-cardiac surgeries. The primary composite endpoint comprised cardiac death, cardiogenic shock, acute coronary syndromes (ACS), and cardiogenic pulmonary edema occurring within 30 days after surgery, while the secondary endpoint was ACS., Results: A total of 1590 patients were enrolled; among them, 669 underwent a MPI stress test strategy (sCMR: 287, SPECT-MPI: 382). The incidence of 30-day cardiac events was lower in the stress-tested group compared to the non-stress-tested group (1.2% vs. 3.4%; p 0.006). Adopting a stress test strategy showed a significant reduction in the risk of the composite endpoint (OR: 0.33, 95% CI: 0.15-0.76, p 0.009) and ACS (OR: 0.41, 95% CI: 0.17-0.98, p 0.046) at multivariable analysis, with similar cardiac events rate between stress CMR and SPECT (1.1% vs. 1.3%, p 0.756). Stress CMR showed a greater accuracy to predict coronary artery revascularizations (sCMR c-statistic: 0.95, ischemic cut-point: 5.5%; SPECT c-statistic: 0.85, ischemic cut-point: 7.5%)., Conclusion: Stress test strategy is related to a lower occurrence of cardiac events in high-risk patients scheduled for intermediate-to-high-risk non-cardiac surgeries. Both sCMR and SPECT-MPI comparably reduce the likelihood of cardiac complications, albeit sCMR offers greater accuracy in predicting coronary artery revascularization., (© 2024. The Author(s).)

Coronary CT angiography (CTA) derived fractional flow reserve (FFR CT ) is recommended for physiological assessment in intermediate coronary stenosis for guiding referral to invasive coronary angiography (ICA). In this study, we report real-world data on the feasibility of implementing a CTA/FFR CT test algorithm as a gatekeeper to ICA at referral hospitals. Retrospective all-comer study of patients with new onset stable symptoms and suspected coronary stenosis (30-89%) by CTA. Evaluation of CTA datasets, interpretation of FFR CT analysis, and decisions on downstream testing were performed by skilled CT-cardiologists. CTA was performed in 3974 patients, of whom 381 (10%) were referred directly to ICA, whereas 463 (12%) to non-invasive functional testing: FFR CT 375 (81%) and perfusion imaging 88 (19%). FFR CT analysis was rejected in 8 (2%) due to inadequate CTA image quality. Number of patients deferred from ICA after FFR CT was 267 (71%), while 100 (27%) were referred to ICA. Obstructive coronary artery disease (CAD) was confirmed in 62 (62%) patients and revascularization performed in 53 (53%). Revascularization rates, n (%), were higher in patients undergoing FFR CT -guided versus CTA-guided referral to ICA: 30-69% stenosis, 28 (44%) versus 8 (21%); 70-89% stenosis, 39 (69%) versus 25 (46%), respectively, both p < 0.05. Implementation of FFR CT at referral hospitals was feasible, reduced the number of invasive procedures, and increased the revascularization rate., (© 2024. The Author(s).)

Background: We aimed to develop a framework for generating three-dimensional (3D) myocardial blood flow (MBF) images, computing their accuracy against clinically validated two-dimensional (2D) polar MBF maps of the left ventricle, and evaluating their improvements in image quality over relative myocardial perfusion imaging (MPI)., Methods: N = 40 patients with a wide range of defect severities and uptake dynamics were retrospectively studied. The FlowQuant™ software was used to generate reference MPI and polar MBF maps and was adapted for voxel-wise MBF mapping. We evaluated agreement between parametric vs polar values for MBF at rest and stress and for reserve (stress/rest MBF). We also assessed improvements in image quality, assessed by signal-to-noise ratio, contrast-to-noise ratio, tissue-to-blood ratio, and defect severity, from relative MPI to MBF., Results: There was excellent agreement between 3D parametric and 2D polar maps for all flow parameters (interclass correlation coefficient >0.96), albeit with minimal bias (<8%) for rest and stress MBF at the patient level. Image quality substantially improved from MPI to MBF in every patient for all image-quality metrics (P < 0.0001) CONCLUSIONS: We developed a robust methodology for producing highly accurate 3D MBF images exhibiting considerably improved image quality compared to relative MPI commonly used in clinical practice., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Various non-invasive images are used in clinical practice for the diagnosis and prognostication of chronic coronary syndromes. Notably, quantitative myocardial perfusion imaging (MPI) through positron emission tomography (PET) has seen significant technical advancements and a substantial increase in its use over the past two decades. This progress has generated an unprecedented wealth of clinical information, which, when properly applied, can diagnose and fine-tune the management of patients with different types of ischemic syndromes. This state-of-art review focuses on quantitative PET MPI, its integration into clinical practice, and how it holds up at the eyes of modern cardiac imaging and revascularization clinical trials, along with future perspectives., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This study aimed to evaluate the impact of acute intravenous beta-blocker administration on myocardial blood flow (MBF) during same-day hybrid coronary computed tomography angiography (CCTA) and 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI). Previous research on the discontinuation of oral beta-blockers before MPI has shown mixed results, with no studies yet exploring the acute intravenous administration in the context of same-day hybrid imaging. This retrospective study included patients with suspected chronic coronary syndromes undergoing same-day hybrid CCTA/13N-ammonia PET MPI. Exclusion criteria comprised coronary artery stenosis ≥ 50% or regional perfusion abnormalities on PET, and baseline oral beta-blocker medication. Intravenous metoprolol (up to 30 mg) was administered as needed for heart rate control before CCTA. MBF measurements were obtained at rest (rMBF) and during stress (sMBF), and myocardial flow reserve (MFR) was calculated. After excluding 281 patients, 154 were eligible for propensity-score matching, resulting in 108 patients divided into two equal groups based on beta-blocker administration. The groups showed no significant differences in baseline characteristics. Among those who received beta-blockers, there was a significant decrease in sMBF (2.21 [IQR 1.72-2.78] versus 2.46 [2.08-2.99] ml∙min -1 ∙g -1 , p = 0.027) and MFR (3.46 [2.70-4.05] versus 3.79 [3.22-4.46], p = 0.030), respectively, compared to those who did not receive beta-blockers. In contrast, rMBF remained unaffected (0.65 [0.54-0.78] versus 0.64 [0.55-0.76] ml∙min -1 ∙g -1 , p = 0.931). Acute intravenous beta-blocker administration significantly impacts MBF, leading to a slight reduction in sMBF and MFR. In contrast, rMBF appears unaffected, suggesting that beta-blockers primarily affect the coronary capacity to respond to vasodilators., (© 2024. The Author(s).)

Objective: Left ventricular dyssynchrony (LVD), the loss of coordinated contraction in the left ventricle, is an early sign of heart failure. LVD can be assessed using phase analysis techniques with gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). This study aimed to investigate the impact of obesity on LVD through phase analysis., Methods: We retrospectively enrolled 152 obese patients and 80 age- and sex-matched nonobese patients who showed normal myocardial perfusion and normal left ventricular ejection fraction (LVEF) on MPI. Phase standard deviation (PSD) and phase histogram bandwidth (PBW), as phase analysis parameters, were compared between patients with and without obesity., Results: Although PSD values were within the normal range (cut-off value >23) for both groups, the PSD values of obese patients were higher than those of the nonobese (20.49 ± 8.66 vs. 14.81 ± 4.93; p < 0.05). PBW values of obese patients were statistically significantly higher than those of the nonobese (57.03 ± 23.17 vs. 41.40 ± 9.96; p < 0.05). The PBW values of obese patients exceeded the normal limits (cut-off value >49). A weak positive correlation was observed between body mass index (BMI) and PBW values in obese patients (r = 0.181, p < 0.05). In patients of normal weight, no correlations were found between BMI and phase analysis parameters., Conclusion: LVD may develop in obese patients, even when myocardial perfusion and ejection fraction are preserved. The use of phase analysis with gated SPECT could be an additional finding improving the early detection of left ventricular dyssynchrony in obese patients., (© 2024 Wiley Periodicals LLC.)

Stable chest pain is a common symptom with multiple potential causes. Non-invasive imaging has an important role in diagnosis and guiding management through the assessment of coronary stenoses, atherosclerotic plaque, myocardial ischaemia or infarction, and cardiac function. Computed tomography (CT) provides the anatomical evaluation of coronary artery disease (CAD) with the assessment of stenosis, plaque type and plaque burden, with additional functional information available from CT fractional flow reserve (FFR) or CT myocardial perfusion imaging. Stress magnetic resonance imaging, nuclear stress myocardial perfusion imaging, and stress echocardiography can assess myocardial ischaemia and other cardiac functional parameters. Coronary CT angiography can be used as a first-line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. Functional testing may be considered for patients with known CAD, where the clinical significance is uncertain based on anatomical testing, or in patients with high pre-test probability. This practice recommendations document can be used to guide the selection of non-invasive imaging for patients with stable chest pain and provides brief recommendations on how to perform and report these diagnostic tests. KEY POINTS: The selection of non-invasive imaging tests for patients with stable chest pain should be based on symptoms, pre-test probability, and previous history. Coronary CT angiography can be used as a first-line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. Functional testing can be considered for patients with known CAD, where the clinical significance of CAD is uncertain based on anatomical testing, or in patients with high pre-test probability. KEY RECOMMENDATIONS: Non-invasive imaging is an important part of the assessment of patients with stable chest pain. The selection of non-invasive imaging test should be based on symptoms, pre-test probability, and previous history. (Level of evidence: High). Coronary CT angiography can be used as a first line test for many patients with stable chest pain, particularly those with low to intermediate pre-test probability. CT provides information on stenoses, plaque type, plaque volume, and if required functional information with CT fractional flow reserve or CT perfusion. (Level of evidence: High). Functional testing can be considered for patients with known CAD, where the clinical significance of CAD is uncertain based on anatomical testing, or in patients with high pre-test probability. Stress MRI, SPECT, PET, and echocardiography can provide information on myocardial ischemia, along with cardiac functional and other information. (Level of evidence: Medium)., (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Objective: To describe clinical, functional, surgical, and outcomes data in pediatric patients with a myocardial bridge (MB) evaluated and managed following a standardized approach., Methods: Prospective observational study included patients evaluated in the Coronary Artery Anomalies Program. Anatomy was determined by computed tomography angiography, myocardial perfusion by stress perfusion imaging, and coronary hemodynamic assessment by cardiac catheterization., Results: In total, 39 of 42 patients with a complete evaluation for MB were included (December 2012 to June 2022) at a median age of 14.1 years (interquartile range, 12.2-16.4). Sudden cardiac arrest occurred in 3 of 39 (8%), exertional symptoms in 14 (36%), and no/nonspecific symptoms in 7 (18%) patients. Exercise stress test was abnormal in 3 of 34 (9%), stress perfusion imaging in 8 of 34 (24%), and resting instantaneous wave-free ratio ≤0.89 or diastolic dobutamine fractional flow reserve ≤0.80 in 11 of 21 (52%) patients. As a result, 15 of 39 (38%) patients were determined to have hemodynamically significant MB, 1 of 15 patients started beta-blocker, and 14 of 15 were referred for surgery. Myotomy (n = 11) and coronary bypass (n = 1) were performed successfully, resulting in improved symptoms and stress testing results. One patient required pericardiocentesis postoperatively, and all were discharged without other complications. At median follow-up time of 2.9 (1.8-5.8) years, all (except 2 pending surgery) were doing well without exercise restriction., Conclusions: Pediatric patients with MB can present with myocardial ischemia and sudden cardiac arrest. Provocative stress test and intracoronary hemodynamic tests helped risk-stratify symptomatic patients with MB and concern for ischemia. Surgical repair was safe and effective in mitigating exertional symptoms and stress test results, allowing patients to return to exercise without restriction., Competing Interests: Conflict of Interest Statement The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (Copyright © 2024 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Aortic perivascular adipose tissue (aPVAT) density is associated with age-related aortic stiffness in humans and therefore, may contribute to cardiovascular dysfunction. A lower subendocardial viability ratio (SEVR), an estimate of myocardial perfusion, indicates greater cardiovascular disease (CVD) risk and is associated with aortic stiffness in clinical populations. However, the influence of aortic stiffness on the relation between aPVAT density and SEVR/cardiovascular (CV) hemodynamics in apparently healthy adults is unknown. We hypothesize that greater aPVAT density will be associated with lower SEVR and higher CV hemodynamics independent of aortic stiffness. Fourteen (6 males/8 females; mean age, 55.4 ± 5.6 yr; body mass index, 25.5 ± 0.6 kg/m 2 ) adults completed resting measures of myocardial perfusion (SEVR), CV hemodynamics (pulse wave analysis), aortic stiffness [carotid-femoral pulse wave velocity (cfPWV)], and a computed tomography scan to acquire aPVAT and visceral adipose tissue (VAT) density. Greater aPVAT density (i.e., higher density) was associated with lower SEVR ( r = -0.78, P < 0.001) and a higher systolic pressure time integral ( r = 0.49, P = 0.03), forward pulse height ( r = 0.49, P = 0.03), reflected pulse height ( r = 0.55, P = 0.02), ejection duration ( r = 0.56, P = 0.02), and augmentation pressure ( r = 0.69, P = 0.003), but not with the diastolic pressure time integral ( r = -0.22, P = 0.22). VAT density was not associated with SEVR or any CV hemodynamic endpoints (all, P > 0.05). Furthermore, the relation between aPVAT density and SEVR remained after adjusting for aortic stiffness ( r = -0.66, P = 0.01) but not age ( r = -0.24, P > 0.05). These data provide initial evidence for aPVAT as a novel yet understudied local fat depot contributing to lower myocardial perfusion in apparently healthy adults with aging. NEW & NOTEWORTHY Aortic perivascular adipose tissue (aPVAT) density is associated with aging and aortic stiffness in humans and, therefore, may contribute to lower myocardial perfusion. We demonstrate that greater aPVAT, but not visceral adipose tissue density is associated with lower myocardial perfusion and augmentation pressure independent of aortic stiffness, but not independent of age. These data provide novel evidence for aPVAT as a potential therapeutic target to improve myocardial perfusion and cardiovascular function in humans with aging.

Aims: This study aimed to assess the impact of adenosine on quantitative myocardial blood flow (MBF) in a rapid stress-rest protocol compared with a rest-stress protocol using 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) and to gain insights into the time dependency of such effects., Methods and Results: Quantitative MBF at rest (rMBF) and during adenosine-induced stress (sMBF) and myocardial flow reserve (MFR) were obtained from 331 retrospectively identified patients who underwent 13N-ammonia PET MPI for suspected chronic coronary syndrome and who all exhibited no perfusion defects. Of these, 146 (44.1%) underwent a rapid stress-rest protocol with a time interval (Δtstress-rest) of 20 ± 4 min between adenosine infusion offset and rest imaging, as per clinical routine. The remaining 185 (55.9%) patients underwent a rest-stress protocol and served as the reference. Groups did not differ regarding demographics, risk factors, medication, left ventricular function, and calcium scores. rMBF was significantly higher in the stress-rest vs. the rest-stress group [0.80 (interquartile range 0.66-1.00) vs. 0.70 (0.58-0.83) mL·min-1·g-1, P < 0.001], and, as sMBF was identical between groups [2.52 (2.20-2.96) vs. 2.50 (1.96-3.11), P = 0.347], MFR was significantly lower in the stress-rest group [3.07 (2.43-3.88) vs. 3.50 (2.63-4.10), P = 0.007]. There was a weak correlation between Δtstress-rest and rMBF (r = -0.259, P = 0.002) and between Δtstress-rest and MFR (r = 0.163, P = 0.049), and the proportion of patients with abnormally high rMBF was significantly decreasing with increasing Δtstress-rest., Conclusion: Intravenously applied adenosine induces a long-lasting hyperaemic effect on the myocardium. Consequently, rapid stress-rest protocols could lead to an overestimation of rMBF and an underestimation of MFR., Competing Interests: Conflict of interest: The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: CMD refers to the abnormalities of the tiny arteries and capillaries within the coronary artery system, which result in restricted or abnormal blood flow. CMD is an important mechanism involved in ischemic heart disease and secondary heart failure. CMD can explain left ventricular dysfunction and poor prognosis.The European Association of Cardiovascular Imaging recommends the use of MCE for the assessment of myocardial perfusion. Myocardial contrast echocardiography (MCE) is used to evaluate the accuracy of Coronary microvascular dysfunction (CMD) for predicting major adverse cardiac events (MACEs) in patients with heart failure with preserved ejection fraction (HFpEF) at follow-up., Methods: The clinical data of 142 patients diagnosed with HFpEF in our hospital from January 2020 to January 2022 were retrospectively summarized and stratified into 77 cases (> 1) in the CMD group and 65 cases (= 1) in the non-CMD group based on the perfusion score index (PSI) of the 17 segments of the left ventricle examined by the admission MCE, and the perfusion parameters were measured at the same time, including the peak plateau intensity (A value), the curve slope of the curve rise (βvalue) and A × β values. At a median follow-up of 27 months till October 2023, MACEs were recorded mainly including heart failure exacerbation, revascularization, cardiac death, etc. RESULTS: Increasing age, hypertension, diabetes, and coronary artery disease in the CMD group resulted in decreased left ventricular ejection fraction (LVEF), increased plasma NT-B-type natriuretic peptide (BNP) and left ventricular global longitudinal strain (LVGLS), decreased A-values and A × β-values, and an increased incidence of MACEs (P < 0.05). Univariate and multivariate Cox regression analyses showed that LVGLS (HR = 1.714, 95% CI = 1.289-2.279, P < 0.001) and A × β values (HR = 0.636, 95% CI = 0.417 to 0.969, P = 0.035) were independent predictors of MACEs in patients with HFpEF. The receiver operating characteristic curve (ROC) showed that the area under the curve (AUC) of LVGLS combined with A × β value for diagnosis of MACEs was 0.861 (95% CI = 0.761 ~ 0.961, P < 0.001), which was significantly higher than that of LVGLS or A × β value (P < 0.05). The Kaplan-Meier survival curves showed that the cumulative survival rate in CMD group was significantly lower than non-CMD group (logrank χ 2  = 6.626, P = 0.010), with the most significant difference at 20 months of follow-up., Conclusion: MCE can evaluate CMD semi-quantitatively and quantitatively, LVGLS combined with A × β value has good performance in predicting the risk of developing MACEs in patients with HFpEF at 3 years of follow-up, and CMD can be used as an important non-invasive indicator for assessing clinical prognosis., (© 2024. The Author(s).)

Background: Myocardial perfusion imaging (MPI) with single photon emission computed tomography is an established non-invasive technique for assessing myocardial ischemia. This method involves the intravenous administration of a radiopharmaceutical that accumulates in the heart muscle proportional to regional blood flow. However, image quality and diagnostic accuracy can be compromised by various technical and patient-related factors, including high non-specific radiopharmaceutical uptake in abdominal organs such as the stomach, intestines, liver, and gall-bladder, leading to subdiaphragmatic artifacts. These artifacts are particularly problematic for evaluating inferior wall perfusion and often necessitate repeated imaging, which decreases gamma camera availability and prolongs imaging times., Conclusions: Despite numerous investigated techniques to reduce interfering gastrointestinal activity, results have been inconsistent, and current MPI guidelines provide scant information on effective procedures to mitigate this issue. Based on our experience, some possible approaches to reducing artifacts include choosing stress testing with an exercise stress test, when possible, late imaging, fluid intake, and consuming carbonated water immediately before imaging., (© 2024 Anja Strok et al., published by Sciendo.)

Objective: Routine screening for cardiovascular disease before kidney transplantation remains controversial. This study aims to compare cardiac testing rates in patients with end-stage renal disease, referred and not referred for transplantation, and assess the impact of testing on transplant wait times., Methods: This is a retrospective cohort study of 22 687 end-stage renal disease patients from 2011 to 2022, within an integrated health system. Cardiac testing patterns, and the association between cardiac testing and transplant wait times and post-transplant mortality were evaluated., Results: Of 22 687 patients (median age 66 years, 41.1% female), 6.9% received kidney transplants, and 21.0% underwent evaluation. Compared with dialysis patients, transplant patients had a 5.6 times higher rate of stress nuclear myocardial perfusion imaging with single-photon emission (rate ratio (RR) 5.64, 95% CI 5.37 to 5.92), a 6.5 times higher rate of stress echocardiogram (RR 6.51, 95% CI 5.65 to 7.51) and 16% higher cardiac catheterisation (RR 1.16, 95% CI 1.06 to 1.27). In contrast, revascularisation rates were significantly lower in transplant patients (RR 0.46, 95% CI 0.36 to 0.58). Transplant wait times were longer for patients who underwent stress testing (median 474 days with no testing vs 1053 days with testing) and revascularisation (1796 days for percutaneous intervention and 2164 days for coronary artery bypass surgery). No significant association was observed with 1-year post-transplant mortality (adjusted OR 1.99, 95% CI 0.46 to 8.56)., Conclusions: This study found a higher rate of cardiac testing in dialysis patients evaluated for kidney transplants. Cardiac testing was associated with longer transplant wait time, but no association was observed between testing and post-transplant mortality., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Chronic Chagas cardiomyopathy (CCC) is caused by an inflammatory process induced by Trypanosoma cruzi, which leads to myocarditis with reactive and reparative fibrosis. CCC progresses with myocardial perfusion abnormalities and histopathological events that affect cardiorespiratory fitness (CRF)., Objectives: We evaluated the effects of aerobic physical training (APT) on myocardial perfusion and on morphological and functional impairments related with inflammation and fibrosis in Syrian hamsters with CCC. As a secondary objective, we analyzed the cross-sectional areas of the skeletal muscle., Methods: Hamsters with CCC and their respective controls were divided into four groups: CCC sedentary, CCC-APT, sedentary control and APT control. Seven months after infection, the animals underwent echocardiography, myocardial perfusion scintigraphy and cardiopulmonary exercise testing. Moderate-intensity APT was performed for fifty minutes, five times a week, for eight weeks. Subsequently, the animals were reassessed. Histopathological analysis was conducted after the above-mentioned procedures. The level of significance was set at 5% in all analyses (p<0.05)., Results: CCC sedentary animals presented worse myocardial perfusion defects (MPD) over time, reduced left ventricle ejection fraction (LVEF) and showed more inflammation and fibrosis when compared to other groups (mixed ANOVA analysis). Conversely, APT was able to mitigate the progression of MPD, ameliorate inflammation and fibrosis and improve CRF efficiency in CCC-APT animals., Conclusions: Our study demonstrated that APT ameliorated cardiac dysfunction, MPD, and reduced inflammation and fibrosis in CCC hamster models. Additionally, CCC-SED animals presented skeletal muscle atrophy while CCC-APT animals showed preserved skeletal muscle CSA. Understanding APT's effects on CCC's pathophysiological dimensions is crucial for future research and therapeutic interventions.

Myocardial perfusion imaging (MPI) provides physiologic and functional information about the heart muscle and its blood flow. Extracardiac radioactivity can interfere with visualization of the inferior wall of the myocardium, leading to poor-quality images, difficulties in interpretation, and delays in routine practice. This study aimed to identify the efficiency of having the patient consume a carbonated lemon drink to minimize the extracardiac radioactivity of 99m Tc-sestamibi in comparison to 99m Tc-tetrofosmin during MPI. Methods: This was a retrospective study that recruited 158 patients with known or suspected coronary artery disease referred to undergo 99m Tc-sestamibi or 99m Tc-tetrofosmin rest/stress single-day MPI. The patients were divided into 2 groups of mixed sexes and different ages. The first group comprised 78 patients injected with 99m Tc-sestamibi, and the second group comprised 80 patients injected with 99m Tc-tetrofosmin. For both groups, the patients drank 30 mL of fresh lemon juice diluted with 150 mL of soda water, and then we gave the patients about 100 mL of straight soda water, before imaging for both the rest and the stress phases. Results: Generally, in both groups, the 99m Tc-tetrofosmin produced a good-quality image in comparison with the 99m Tc-sestamibi. The mean rank of the total score for 99m Tc-tetrofosmin (62.75) was less than that for 99m Tc-sestamibi (96.68), and this difference was highly statistically significant ( P = 0.000). There were statistically significant differences in the ratios and mean ranks for both groups in favor of 99m Tc-tetrofosmin in patients having coronary artery disease. Conclusion: The use of a carbonated lemon drink minimizes extracardiac activity from both 99m Tc-labeled MPI radiopharmaceuticals. This finding was more statistically significant for 99m Tc-tetrofosmin MPI, providing better image quality and earlier imaging in both the rest and the stress phases because of faster hepatobiliary clearance., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: Adverse left ventricular remodeling is a significant cardiovascular predictor for patients with coronary artery disease and preserved left ventricular ejection fraction (LVEF). However, the remodeling indexes reflecting left ventricular spherization by myocardial perfusion imaging are underexplored., Methods and Results: 727 patients (mean age 59.8±13.5 years, 329 women) diagnosed or suspected coronary artery disease with preserved LVEF who underwent resting myocardial perfusion imaging were retrospectively enrolled. The myocardial perfusion imaging findings including the total perfusion deficit and sphericity indexes (shape index (SI) and eccentricity index (EI) obtained from gated (QGS) and non-gated (QPS) images) were collected. Major adverse cardiovascular events (MACE) were followed up for 45.1±22.0 months. All patients were divided into 4 subgroups based on total perfusion deficit at 10% and LVEF at 65%. Univariable comparative analyses were performed in 5 cohorts (all patients and 4 subgroups). Patients who experienced MACE displayed higher SI and/or lower EI (all P <0.05). Kaplan-Meier survival analyses suggested significant differences for SI QPS in all 5 cohorts, for EI QPS and EI QGS in 4 cohorts, and for end-systolic and end-diastolic SI QGS in 3 cohorts (all  P <0.05). Multivariate Cox analysis showed that abnormal SI and EI remained statistically significant predictors for MACE after adjusting for total perfusion deficit, LVEF, and other confounding factors., Conclusions: For patients diagnosed or suspected of coronary artery disease with preserved or supra-normal LVEF, resting sphericity indexes by myocardial perfusion imaging displayed incremental long-term prognostic value. Among these indicators, SI QPS is particularly promising across different perfusion or preserved functional conditions.

Background: The value of physiological ischemia versus anatomic severity of disease for prognosis and management of patients with stable coronary artery disease (CAD) is widely debated., Methods: A total of 1764 patients who had rest-stress cadmium-zinc-telluride single-photon emission computed tomography myocardial perfusion imaging and angiography (invasive or computed tomography) were prospectively enrolled and followed for cardiac death/nonfatal myocardial infarction. The CAD prognostic index (CADPI) was used to quantify the extent and severity of angiographic disease. Prognostic value was assessed using Cox models, adjusted for pretest risk, known CAD, stressor, left ventricular ejection fraction, %ischemia and infarct, CADPI, and early (90-day) revascularization. Incremental prognostic value was evaluated using net reclassification index., Results: The mean age was 69.7±9.5 years, 24.4% were women, and 29.3% had known CAD. Significant ischemia (>10%) was present in 28.4%. Nonobstructive, single, and multivessel disease was present in 256 (14.5%), 772 (43.8%), and 736 (41.7%), respectively. Early revascularization occurred in 579 (32.8%). Cardiac death/myocardial infarction occurred in 148 (8.4%) over a 4.6-year median follow-up. Both %ischemia and CADPI provided independent and incremental prognostic value over pretest clinical risk ( P <0.001). In a model containing both ischemia and anatomy, ischemia was prognostic (hazard ratio per 5% ↑, 1.35 [95% CI, 1.11-1.63]; P =0.002) but CADPI was not (hazard ratio per 10-unit ↑, 1.09 [95% CI, 0.99-1.20]; P =0.07). Early revascularization modified the risk associated with %ischemia (interaction P =0.003) but not with CADPI (interaction P =0.6). %Ischemia and single-photon emission computed tomography variables added incremental prognostic value over clinical risk and CADPI (net reclassification index, 20.3% [95% CI, 9%-32%]; P <0.05); however, CADPI was not incrementally prognostic beyond pretest risk, %ischemia, and single-photon emission computed tomography variables (net reclassification index, 3.1% [95% CI, -5% to 15%]; P =0.21)., Conclusions: Ischemic burden provides independent and incremental prognostic value beyond CAD anatomy and identifies patients who benefit from early revascularization. The anatomic extent of disease has independent prognostic value over clinical risk factors but offers limited incremental benefit for prognosis and guiding revascularization beyond physiological severity (ischemia)., Competing Interests: Dr Patel reports receiving funding from the National Institutes of Health (award numbers: R03AG082994 and 5P30AG028741-07) and an institutional research grant from Jubilant DraxImage. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The other authors report no conflicts.

Competing Interests: None.

Competing Interests: Beijing Luhe Hospital received free ferumoxytol sponsorship from Chia Tai Tianqing Pharmaceutical Group Co, Ltd. The authors report no conflict.

This study aimed to assess the diagnostic efficacy of left ventricular synchrony (LVS) for detecting coronary artery disease (CAD). We explored whether the LVS index derived from phase analysis of D-SPECT provides superior diagnostic value compared to conventional perfusion analysis in identifying obstructive CAD. Patients with suspected or confirmed CAD underwent drug-stress/rest gated D-SPECT myocardial perfusion imaging (MPI) and coronary angiography (CAG). A 50% stenosis was set as the threshold for obstructive CAD. 110 participants were enrolled in this analysis. There were significant differences in phase standard deviation (PSD), phase histogram bandwidth (PHB) and entropy among the four groups. Patients without cardiac disease and those with mild-moderate stenosis exhibited no noticeable contraction asynchrony. However, LVS indices demonstrated a gradual increase with the progression of coronary stenosis when compared to NC (P < 0.001). Obstructive CAD was identified in 43 out of 110 participants (39%). Optimal cutoff values for diagnosing obstructive CAD during stress were determined as 7.6° for PSD, 24° for PHB, and 37% for entropy, respectively. Notably, PSD, PHB, and entropy indices exhibited higher sensitivity compared to MPI. The integration of the stress-induced LVS indices into routine MPI analysis resulted in a significantly greater area under the curve (AUC), leading to improved diagnostic performance and enhanced differential capacity. Stress-induced LVS indices increase with the severity of coronary artery stenosis by D-SPECT phase analysis. Further, the indices-derived phase analysis exhibits superior sensitivity and discriminatory ability compared to MPI in detecting obstructive CAD., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Objectives: To compare the diagnostic performance of machine learning (ML)-based computed tomography-derived fractional flow reserve (CT-FFR) and cardiac magnetic resonance (MR) perfusion mapping for functional assessment of coronary stenosis., Methods: Between October 2020 and March 2022, consecutive participants with stable coronary artery disease (CAD) were prospectively enrolled and underwent coronary CTA, cardiac MR, and invasive fractional flow reserve (FFR) within 2 weeks. Cardiac MR perfusion analysis was quantified by stress myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). Hemodynamically significant stenosis was defined as FFR ≤ 0.8 or > 90% stenosis on invasive coronary angiography (ICA). The diagnostic performance of CT-FFR, MBF, and MPR was compared, using invasive FFR as a reference., Results: The study protocol was completed in 110 participants (mean age, 62 years ± 8; 73 men), and hemodynamically significant stenosis was detected in 36 (33%). Among the quantitative perfusion indices, MPR had the largest area under receiver operating characteristic curve (AUC) (0.90) for identifying hemodynamically significant stenosis, which is in comparison with ML-based CT-FFR on the vessel level (AUC 0.89, p = 0.71), with comparable sensitivity (89% vs 79%, p = 0.20), specificity (87% vs 84%, p = 0.48), and accuracy (88% vs 83%, p = 0.24). However, MPR outperformed ML-based CT-FFR on the patient level (AUC 0.96 vs 0.86, p = 0.03), with improved specificity (95% vs 82%, p = 0.01) and accuracy (95% vs 81%, p < 0.01)., Conclusion: ML-based CT-FFR and quantitative cardiac MR showed comparable diagnostic performance in detecting vessel-specific hemodynamically significant stenosis, whereas quantitative perfusion mapping had a favorable performance in per-patient analysis., Clinical Relevance Statement: ML-based CT-FFR and MPR derived from cardiac MR performed well in diagnosing vessel-specific hemodynamically significant stenosis, both of which showed no statistical discrepancy with each other., Key Points: • Both machine learning (ML)-based computed tomography-derived fractional flow reserve (CT-FFR) and quantitative perfusion cardiac MR performed well in the detection of hemodynamically significant stenosis. • Compared with stress myocardial blood flow (MBF) from quantitative perfusion cardiac MR, myocardial perfusion reserve (MPR) provided higher diagnostic performance for detecting hemodynamically significant coronary artery stenosis. • ML-based CT-FFR and MPR from quantitative cardiac MR perfusion yielded similar diagnostic performance in assessing vessel-specific hemodynamically significant stenosis, whereas MPR had a favorable performance in per-patient analysis., (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Background: Although positron emission tomography (PET) imaging is well established for its diagnostic role in cardiac sarcoidosis, less is known about the prognostic value of PET and its use in risk stratification for major adverse cardiac events (MACE)., Objectives: The goal of this study was to perform a systematic review and meta-analysis looking at the prognostic value of PET imaging in patients with cardiac sarcoidosis., Methods: Study investigators systematically searched EMBASE (Excerpta Medica dataBASE), MEDLINE, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL (Cumulative Index to Nursing and Allied Health Literature), ClinicalTrials.gov, and the European Union Clinical Trial Registry for cardiac sarcoidosis and PET imaging. The primary outcome of interest was MACE., Results: The search revealed 3,010 records, of which 55 studies were included. This represented 5,250 patients. Factors associated with MACE included the following: the combination of abnormal fluorodeoxyglucose (FDG) uptake and perfusion defect, which had an OR of 2.86 (95% CI: 1.74-4.71; P < 0.0001); abnormal perfusion or FDG uptake, which had an OR of 2.69 (95% CI: 1.67-4.33); abnormal FDG uptake, which had an OR of 2.61 (95% CI: 1.51-4.50); focal abnormal right ventricular uptake, which had an OR of 6.27 (95% CI: 3.19-12.32; P < 0.00001); and a lack of response to immunosuppression on serial PET, which had an OR of 8.43 (95% CI: 3.25-21.85; P < 0.0001). A QUIPS (Quality in Prognostic Studies) tool analysis found a low to moderate risk of bias, particularly given the small sample sizes in the individual studies., Conclusions: Multiple cardiac PET parameters provide risk stratification value in cardiac sarcoidosis. Focal right ventricular uptake and a lack of response to immunosuppressive therapy on serial PET imaging were particularly predictive of MACE., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: To develop and evaluate a deep learning (DL) -based rapid image reconstruction and motion correction technique for high-resolution Cartesian first-pass myocardial perfusion imaging at 3T with whole-heart coverage for both single-slice (SS) and simultaneous multi-slice (SMS) acquisitions., Methods: 3D physics-driven unrolled network architectures were utilized for the reconstruction of high-resolution Cartesian perfusion imaging. The SS and SMS multiband (MB) = 2 networks were trained from 135 slices from 20 subjects. Structural similarity index (SSIM), peak SNR (PSNR), and normalized RMS error (NRMSE) were assessed, and prospective images were blindly graded by two experienced cardiologists (5, excellent; 1, poor). For respiratory motion correction, a 2D U-Net based motion corrected network was proposed, and the temporal fidelity and second-order derivative were calculated to assess the performance of the motion correction., Results: Excellent performance was demonstrated in the proposed technique with high SSIM and PSNR, and low NRMSE. Image quality scores were (4.3 [4.3, 4.4], 4.5 [4.4, 4.6], 4.3 [4.3, 4.4], and 4.5 [4.3, 4.5]) for SS DL and SS L1-SENSE, MB = 2 DL and MB = 2 SMS-L1-SENSE, respectively, showing no statistically significant difference (p > 0.05 for SS and SMS) between (SMS)-L1-SENSE and the proposed DL technique. The network inference time was around 4 s per dynamic perfusion series with 40 frames while the time of (SMS)-L1-SENSE with GPU acceleration was approximately 30 min., Conclusion: The proposed DL-based image reconstruction and motion correction technique enabled rapid and high-quality reconstruction for SS and SMS MB = 2 high-resolution Cartesian first-pass perfusion imaging at 3T., (© 2024 International Society for Magnetic Resonance in Medicine.)

Coronary heart disease (CHD) remains the top cause of death due to cardiovascular conditions worldwide, with someone suffering a myocardial infarction every 40 seconds. This highlights the importance of non-invasive imaging technologies like myocardial perfusion imaging (MPI), which are crucial for detecting coronary artery disease (CAD) early, even before symptoms appear. However, the reliance solely on MPI has shifted due to its limitations in definitively ruling out atherosclerosis, leading to the adoption of hybrid imaging techniques. Hybrid imaging combines computed tomography (CT) with MPI techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT). This integration, often within a single gantry system, enhances the diagnostic accuracy by allowing for attenuation correction (AC), acquisition of the coronary artery calcium score (CACS), and more precise tracing of radiotracer uptake. The built-in CT in modern MPI systems assists in these functions, which is essential for better diagnosis and risk assessment in patients. The addition of CACS to MPI, a method involving the assessment of calcified plaque in coronary arteries, notably enhances diagnostic and prognostic capabilities. CACS helps in identifying atherosclerosis and predicting potential cardiac events, facilitating personalized risk management and the initiation of tailored interventions like statins and aspirin. Such comprehensive imaging strategies not only improve the accuracy of detecting CAD but also help in stratifying patient risk more effectively. In this paper, we discuss how the incorporation of CAC into MPI protocols enhances the diagnostic sensitivity for detecting obstructive CAD, as evidenced by several studies where the addition of CAC to MPI has led to improved outcomes in diagnosing CAD. Moreover, CAC has been shown to unmask silent coronary atherosclerosis in patients with normal MPI results, highlighting its incremental diagnostic value. We will discuss the evolving role of hybrid imaging in guiding therapeutic decisions, particularly the use of statins for cardiovascular prevention. The integration of CAC assessment with MPI not only aids in the early detection and management of CAD but also optimizes therapeutic strategies, enhancing patient care through a more accurate and personalized approach. Such advancements underscore the need for further research to fully establish the benefits of combining CAC with MPI in the clinical assessment of cardiovascular risk., Competing Interests: Declaration of competing interest Dr AL-Mallah is a consultant for Jubilant and Pfizer. He received a research grant from Siemens. All other authors have no disclosures., (Copyright © 2024. Published by Elsevier Inc.)

Background: The utility of radionuclide myocardial perfusion imaging including positron emission tomography (PET) for diagnosing mental stress-induced myocardial ischemia (MSIMI) is clinically restricted. This study aims to assess the diagnostic performance of novel echocardiographic techniques, including automated strain and quantitative myocardial contrast echocardiography (MCE) with dedicated software and deep neural network model, for MSIMI detection. The secondary objective was to explore the correlation between changes in myocardial blood flow and MSIMI., Methods: Seventy-two female patients ages 18 to 75 with angina and nonobstructive coronary artery disease (ANOCA) and 23 healthy controls were prospectively recruited. Both echocardiography with contrast agent and PET imaging were performed during structured mental stress testing. Mental stress-induced myocardial ischemia was defined as a summed difference score ≥3 on PET. Echocardiographic parameters including left ventricular global longitudinal strain, β, and A × β were obtained, and their trends during mental stress testing were observed. ΔGLS was defined as the ratio of difference between global longitudinal strain values at stress and rest to the rest data. β reserve and A×β reserve were respectively calculated., Results: Thirty-two ANOCA patients (44%) and 1 control (4%) were diagnosed with MSIMI (P < .01). For ANOCA patients with MSIMI, left ventricular GLS, β, and A × β declined to varied extents during mental stress testing compared with those without MSIMI and the controls (P < .05). Bland-Altman plots demonstrated good consistency between β reserve and A × β reserve output by the deep neural network model and iMCE software. Receiver operating characteristic curve analyses showed that ΔGLS, β reserve, and A × β reserve demonstrated favorable ability to predict MSIMI, especially the combination of A × β reserve using iMCE analysis and ΔGLS (area under the curve, 0.94; sensitivity, 83%; specificity, 97%)., Conclusions: Novel technologies in echocardiography exhibit the potential to be a clinical alternative to cardiac PET for effectively detecting MSIMI. Attenuated myocardial blood flow response during structured mental stress testing was correlated with MSIMI, providing a reasonable explanation for the chest discomfort persisting in ANOCA women., Competing Interests: Disclosures None., (Copyright © 2024 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Purpose: To examine myocardial perfusion and T1 mapping indicesin individuals with type 2 diabetes mellitus (T2DM) at various stages of glycemic control and whether uncontrolled glycemic levels would worsen myocardial microvascular function., Method: Cardiac magnetic resonance examinations were performed on 114 T2DM patients without obstructive coronary artery disease and 55 matched controls. Participants were further divided into four subgroups: Q1 (control); Q2 (prediabetes); Q3 (controlled T2DM) and Q4 (uncontrolled T2DM). The correlation between glycosylated hemoglobin (HbA1c) levels and myocardial perfusion parameters was evaluated., Results: Global myocardial perfusion reserve index (MPRI) was significantly reduced in the Q3 and Q4 subgroups compared to the Q1 or Q2 subgroup (all P<0.001). Compared with the Q1 subgroup, global stress T1 reactivity (stress ΔT1) was significantly reduced in the Q3 and Q4 subgroups (P=0.004 and < 0.001, respectively), but elevated in the Q2 subgroup (P=0.018). Global extracellular volume (ECV) was considerably higher in the Q2 subgroup and gradually rose in the Q3 and Q4 subgroups compared to the Q1 subgroup (P=0.011, 0.001, and 0.007, respectively). HbA1c levels correlated negatively with global MPRI and stress ΔT1, but positively with global ECV (β = -1.993, P<0.001; β = -0.180, P<0.001; and β = 0.127, P<0.001, respectively)., Conclusions: Global stress ΔT1 reduced in T2DM patients but rose in prediabetes patients. Compared to MPRI, the ECV parameter can indicate diabetes-induced coronary microvascular dysfunction earlier and persists throughout the disorder. Myocardial perfusion and T1 mapping at stress can be used to detect early signs of microvascular dysfunction and subclinical risk factors in patients with T2DM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Myocardial perfusion imaging (MPI), using either single photon emission computed tomography (SPECT) or positron emission tomography (PET), is one of the most commonly ordered cardiac imaging tests, with prominent clinical roles for disease diagnosis and risk prediction. Artificial intelligence (AI) could potentially play a role in many steps along the typical MPI workflow, from image acquisition through to clinical reporting and risk estimation. AI can be utilized to improve image quality, reducing radiation exposure and image acquisition times. Once images are acquired, AI can help optimize motion correction and image registration during image reconstruction or provide direct image attenuation correction. Utilizing these image sets, AI can segment a number of anatomic features from associated computed tomographic imaging or even generate synthetic attenuation imaging. Lastly, AI may play an important role in disease diagnosis or risk prediction by combining the large number of potentially important clinical, stress, and imaging-related variables. This review will focus on the most recent developments in the field, providing clinicians and researchers with a timely update on the field. Additionally, it will discuss future trends including applications of AI during multiple points of the typical MPI workflow to maximize clinical utility and methods to maximize the information that can be obtained from hybrid imaging., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective. The benefit of percutaneous coronary intervention (PCI) in chronic complete coronary artery occlusion (CTO) remains controversial. PCI is currently indicated only for symptom and myocardial ischemia abolition, but large chronically occluded vessels with extensive afferent myocardial territories may benefit most from this procedure. The noninvasive evaluation of myocardial perfusion is critical before and after revascularization, and positron emission tomography (PET) can determine absolute myocardial perfusion. Here, we aimed to explore and compare myocardial perfusion in CTO territories and their remote associated areas before and after PCI. Design. We searched for relevant articles published before November 28, 2022, in the Cochrane Library and PubMed. We calculated 95% confidence intervals (CIs) and standardized mean differences (SMDs) for parameters related to myocardial perfusion in CTO territories and remote areas in CTO patients before and after PCI. Results. We included five studies published between 2017 and 2022, with a total of 592 patients. Stress myocardial blood flow (MBF) was increased in CTO territories after PCI when compared to pre-PCI (mean difference [MD]: 1.70, 95% confidence interval [CI] 1.33-2.08, p  < 0.001). Coronary flow reserve ( CFR) in CTO regions was also higher after PCI (MD 1.37,95% [CI]1.13-1.61, p  < 0.001). Stress MBF in remote regions was also increased after PCI (MD 0.27,95% [CI]0.99 ∼ 0.45, p  = 0.004), as was CFR in remote regions (MD 0.32,95% [CI] 0.14-0.5, p  = 0.001). Conclusions. According to our pooled analysis of current literature, there was an increase in stress MBF and CFR in both CTOs and remote regions after PCI, suggesting that patients with CTO have widespread recovery of blood perfusion after the procedure. These results provide evidence that patients with CTO arteries and high ischemic burdens would indeed benefit from CTO-PCI. Future research on the correlation of ischemia burden reduction with hard clinical endpoints would contribute to a clearer demarcation of the role of CTO PCI with prognostic potential.

Aims: The study aimed, firstly, to validate automatically and visually scored coronary artery calcium (CAC) on low-dose computed tomography (CT) (LDCT) scans with a dedicated calcium scoring CT (CSCT) scan and, secondly, to assess the added value of CAC scored from LDCT scans acquired during [15O]-water-positron emission tomography (PET) myocardial perfusion imaging (MPI) on prediction of major adverse cardiac events (MACE)., Methods and Results: Five hundred seventy-two consecutive patients with suspected coronary artery disease, who underwent [15O]-water-PET MPI with LDCT and a dedicated CSCT scan were included. In the reference CSCT scans, manual CAC scoring was performed, while LDCT scans were scored visually and automatically using deep learning approach. Subsequently, based on CAC score results from CSCT and LDCT scans, each patient's scan was assigned to one out of five cardiovascular risk groups (0, 1-100, 101-400, 401-1000, >1000), and the agreement in risk group classification between CSCT and LDCT scans was investigated. MACE was defined as a composite of all-cause death, non-fatal myocardial infarction, coronary revascularization, and unstable angina. The agreement in risk group classification between reference CSCT manual scoring and visual/automatic LDCT scoring from LDCT was 0.66 [95% confidence interval (CI): 0.62-0.70] and 0.58 (95% CI: 0.53-0.62), respectively. Based on visual and automatic CAC scoring from LDCT scans, patients with CAC > 100 and CAC > 400, respectively, were at increased risk of MACE, independently of ischaemic information from the [15O]-water-PET scan., Conclusion: There is a moderate agreement in risk classification between visual and automatic CAC scoring from LDCT and reference CSCT scans. Visual and automatic CAC scoring from LDCT scans improve identification of patients at higher risk of MACE., Competing Interests: Conflict of interest: N.R.v.d.W. is an employee of Philips. I.I. received institutional research grants from Dutch Technology Foundation (P15–26) with participation of Philips Healthcare and Pie Medical Imaging BV and institutional research grant from Pie Medical Imaging BV., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: We aimed to test the hypothesis if combining coronary artery calcium score (Ca-score) as a quantitative anatomical marker of coronary atherosclerosis with high-sensitivity cardiac troponin as a quantitative biochemical marker of myocardial injury provided incremental value in the detection of functionally relevant coronary artery disease (fCAD) and risk stratification., Methods and Results: Consecutive patients undergoing myocardial perfusion single-photon emission computed tomography (MPS) without prior CAD were enrolled. The diagnosis of fCAD was based on the presence of ischaemia on MPS and coronary angiography; fCAD was centrally adjudicated in the diagnostic and prognostic domain. Diagnostic accuracy was evaluated using the area under the receiver-operating characteristic curve (AUC). The composite of cardiovascular death and non-fatal acute myocardial infarction (AMI) within 730 days was the primary prognostic endpoint. Among 1715 patients eligible for the diagnostic analysis, 399 patients had fCAD. The combination of Ca-score and high-sensitivity cardiac troponin T (hs-cTnT) had good diagnostic accuracy for the diagnosis of fCAD (AUC 0.79, 95% confidence interval (CI) 0.77-0.81), but no incremental value compared with the Ca-score alone (AUC 0.79, 95% CI 0.77-0.81, P = 0.965). Similar results were observed using high-sensitivity cardiac troponin I (AUC 0.80, 95% CI 0.77-0.82) instead of hs-cTnT. Among 1709 patients (99.7%) with available follow-up, 59 patients (3.5%) suffered the composite primary prognostic endpoint (non-fatal AMI, n = 34; CV death, n = 28). Both Ca-score and hs-cTnT had independent prognostic value. Increased risk was restricted to patients with elevation in both markers., Conclusion: The combination of the Ca-score with hs-cTnT increases the prognostic accuracy for future events but does not provide incremental value vs. the Ca-score alone for the diagnosis of fCAD., Study Registration: Clinical trial registration: NCT00470587., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Patients with low HEART (History, Electrocardiogram, Age, Risk factors, and Troponin level) risk scores who are discharged from the emergency department (ED) may present clinical challenges and diagnostic dilemmas. The use of downstream non-invasive stress imaging (NISI) tests in this population remains uncertain. Therefore, this study aims to investigate the value of NISI in risk stratification and predicting cardiac events in patients with low-risk HEART scores (LRHSs)., Methods: We prospectively included 1384 patients with LRHSs between March 2019 and March 2021. All the patients underwent NISI (involving myocardial perfusion imaging/stress echocardiography). The primary endpoints included cardiac death, non-fatal myocardial infarction and unplanned coronary revascularisation. Secondary endpoints encompassed cardiovascular-related admissions or ED visits., Results: The mean patient age was 64±14 years, with 670 (48.4%) being women. During the 634±104 days of follow-up, 58 (4.2%) patients experienced 62 types of primary endpoints, while 60 (4.3%) developed secondary endpoints. Multivariable Cox models, adjusted for clinical and imaging variables, showed that diabetes (HR: 2.38; p=0.008), HEART score of 3 (HR: 1.32; p=0.01), history of coronary artery disease (HR: 2.75; p=0.003), ECG changes (HR: 5.11; p<0.0001) and abnormal NISI (HR: 16.4; p<0.0001) were primary endpoint predictors, while abnormal NISI was a predictor of secondary endpoints (HR: 3.05; p<0.0001)., Conclusions: NISI significantly predicted primary cardiac events and cardiovascular-related readmissions/ED visits in patients with LRHSs., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Patients with diabetes have an increased risk of developing heart failure with preserved ejection fraction (HFpEF). This study aimed to compare indices of myocardial deformation and perfusion between patients with type 2 diabetes mellitus (T2DM) with and without HFpEF and to investigate the relationship between myocardial strain and perfusion reserve., Methods: This study included 156 patients with T2DM without obstructive coronary artery disease (CAD) and 50 healthy volunteers who underwent cardiac magnetic resonance (CMR) examination at our center. Patients with T2DM were subdivided into the T2DM-HFpEF (n = 74) and the T2DM-non-HFpEF (n = 82) groups. The parameters of left ventricular (LV) and left atrial (LA) strain as well as stress myocardial perfusion were compared. The correlation between myocardial deformation and perfusion parameters was also assessed. Mediation analyses were used to evaluate the direct and indirect effects of T2DM on LA strain., Results: Patients with T2DM and HFpEF had reduced LV radial peak systolic strain rate (PSSR), LV circumferential peak diastolic strain rate (PDSR), LA reservoir strain, global myocardial perfusion reserve index (MPRI), and increased LA booster strain compared to patients with T2DM without HFpEF (all P < 0.05). Furthermore, LV longitudinal PSSR, LA reservoir, and LA conduit strain were notably impaired in patients with T2DM without HFpEF compared to controls (all P < 0.05), but LV torsion, LV radial PSSR, and LA booster strain compensated for these alterations (all P < 0.05). Multivariate linear regression analysis demonstrated that LA reservoir and LA booster strain were independently associated with global MPRI (β = 0.259, P < 0.001; β =  - 0.326, P < 0.001, respectively). Further, the difference in LA reservoir and LA booster strain between patients with T2DM with and without HFpEF was totally mediated by global MPRI. Global stress PI, LA booster, global rest PI, and global MPRI showed high accuracy in diagnosing HFpEF among patients with T2DM (areas under the curve [AUC]: 0.803, 0.790, 0.740, 0.740, respectively)., Conclusions: Patients with T2DM and HFpEF exhibited significant LV systolic and diastolic deformation, decreased LA reservoir strain, severe impairment of myocardial perfusion, and elevated LA booster strain that is a compensatory response in HFpEF. Global MPRI was identified as an independent influencing factor on LA reservoir and LA booster strain. The difference in LA reservoir and LA booster strain between patients with T2DM with and without HFpEF was totally mediated by global MPRI, suggesting a possible mechanistic link between microcirculation impairment and cardiac dysfunction in diabetes. Myocardial perfusion and LA strain may prove valuable for diagnosing and managing HFpEF in the future., (© 2024. The Author(s).)

Background: We prospectively assessed the reproducibility of a novel low-dose single-volume dynamic computed tomography (CT) myocardial blood flow measurement technique., Methods: Thirty-four pairs of measurements were made under rest and stress conditions in 13 swine (54.3 ± 12.3 kg). One or two acquisition pairs were acquired in each animal with a 10-min delay between each pair. Contrast (370 mgI/mL; 0.5 mL/kg) and a diluted contrast/saline chaser (0.5 mL/kg; 30:70 contrast/saline) were injected peripherally at 5 mL/s, followed by bolus tracking and acquisition of a single volume scan (100 kVp; 200 mA) with a 320-slice CT scanner. Bolus tracking and single volume scan data were used to derive perfusion in mL/min/g using a first-pass analysis model; the coronary perfusion territories of the left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) were automatically assigned using a previously validated minimum-cost path technique. The reproducibility of CT myocardial perfusion measurement within the LAD, LCx, RCA, and the whole myocardium was assessed via regression analysis. The average CT dose index (CTDI) of perfusion measurement was recorded., Results: The repeated first (P myo1 ) and second (P myo2 ) single-volume CT perfusion measurements were related by P myo2 = 1.01P myo1 - 0.03(ρ = 0.96; RMSE = 0.08 mL/min/g; RMSE = 0.07 mL/min/g) for the whole myocardium, and by P reg2 = 0.86P reg1 + 0.13(ρ = 0.87; RMSE = 0.31 mL/min/g; RMSE = 0.29 mL/min/g) for the LAD, LCx, and RCA perfusion territories. The average CTDI of the single-volume CT perfusion measurement was 10.5 mGy., Conclusion: The single-volume CT blood flow measurement technique provides reproducible low-dose myocardial perfusion measurement using only bolus tracking data and a single whole-heart volume scan., Relevance Statement: The single-volume CT blood flow measurement technique is a noninvasive tool that reproducibly measures myocardial perfusion and provides coronary CT angiograms, allowing for simultaneous anatomic-physiologic assessment of myocardial ischemia., Key Points: A low-dose single-volume dynamic CT myocardial blood flow measurement technique is reproducible. Motion misregistration artifacts are eliminated using a single-volume CT perfusion technique. This technique enables combined anatomic-physiologic assessment of coronary artery disease., (© 2024. The Author(s).)

Competing Interests: Funding Support and Author Disclosures Drs Sanchis and Freixa are proctors for Abbott Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: High levels of catecholamines are cardiotoxic and associated with stress-induced cardiomyopathies. Using a septic shock model that reproduces the reversible cardiomyopathy seen over 10 days associated with human septic shock, we investigated the effects of catecholamines on microcirculatory perfusion and cardiac dysfunction., Methods and Results: Purpose-bred beagles received intrabronchial Staphylococcus aureus (n=30) or saline (n=6). The septic animals were than randomized to epinephrine (1 μg/kg per minute, n=15) or saline (n=15) infusions from 4 to 44 hours. Serial cardiac magnetic resonance imaging, catecholamine levels, and troponins were collected over 92 hours. Serial adenosine-stress perfusion cardiac magnetic resonance imaging was performed on septic animals randomized to receive saline (n=8 out of 15) or epinephrine (n=8 out of 15). High-dose sedation was given to suppress endogenous catecholamine release. Despite catecholamine levels largely remaining within the normal range throughout, by 48 hours, septic animals receiving saline versus nonseptic animals still developed significant worsening of left ventricular ejection fraction, circumferential strain, and ventricular-aortic coupling. In septic animals that received epinephrine versus saline infusions, plasma epinephrine levels increased 800-fold, but epinephrine produced no significant further worsening of left ventricular ejection fraction, circumferential strain, or ventricular-aortic coupling. Septic animals receiving saline had a significant increase in microcirculatory reserve without troponin elevations. Septic animals receiving epinephrine had decreased edema, blunted microcirculatory perfusion, and elevated troponin levels that persisted for hours after the epinephrine infusion stopped., Conclusions: Cardiac dysfunction during sepsis is not primarily due to elevated endogenous or exogenous catecholamines nor due to decreased microvascular perfusion-induced ischemia. However, epinephrine itself has potentially harmful long-lasting ischemic effects during sepsis including impaired cardiac microvascular perfusion that persists after stopping the infusion.

Introduction: Myocardial perfusion imaging (MPI) is one of the most commonly ordered cardiac imaging tests. Accurate motion correction, image registration, and reconstruction are critical for high-quality imaging, but this can be technically challenging and has traditionally relied on expert manual processing. With accurate processing, there is a rich variety of clinical, stress, functional, and anatomic data that can be integrated to guide patient management., Areas Covered: PubMed and Google Scholar were reviewed for articles related to artificial intelligence in nuclear cardiology published between 2020 and 2024. We will outline the prominent roles for artificial intelligence (AI) solutions to provide motion correction, image registration, and reconstruction. We will review the role for AI in extracting anatomic data for hybrid MPI which is otherwise neglected. Lastly, we will discuss AI methods to integrate the wealth of data to improve disease diagnosis or risk stratification., Expert Opinion: There is growing evidence that AI will transform the performance of MPI by automating and improving on aspects of image acquisition and reconstruction. Physicians and researchers will need to understand the potential strengths of AI in order to benefit from the full clinical utility of MPI.

Background CT-derived fractional flow reserve (CT-FFR) and dynamic CT myocardial perfusion imaging enhance the specificity of coronary CT angiography (CCTA) for ruling out coronary artery disease (CAD). However, evidence on comparative diagnostic value remains scarce. Purpose To compare the diagnostic accuracy of CCTA plus CT-FFR, CCTA plus CT perfusion, and sequential CCTA plus CT-FFR and CT perfusion for detecting hemodynamically relevant CAD with that of invasive angiography. Materials and Methods This secondary analysis of a prospective study included patients with chest pain referred for invasive coronary angiography at nine centers from July 2016 to September 2019. CCTA and CT perfusion were performed with third-generation dual-source CT scanners. CT-FFR was assessed on-site. Independent core laboratories analyzed CCTA alone, CCTA plus CT perfusion, CCTA plus CT-FFR, and a sequential approach involving CCTA plus CT-FFR and CT perfusion for the presence of hemodynamically relevant stenosis. Invasive coronary angiography with invasive fractional flow reserve was the reference standard. Diagnostic accuracy metrics and the area under the receiver operating characteristic curve (AUC) were compared with the Sign test and DeLong test. Results Of the 105 participants (mean age, 64 years ± 8 [SD]; 68 male), 49 (47%) had hemodynamically relevant stenoses at invasive coronary angiography. CCTA plus CT-FFR and CCTA plus CT perfusion showed no evidence of a difference for participant-based sensitivities (90% vs 90%, P > .99), specificities (77% vs 79%, P > .99) and vessel-based AUCs (0.84 [95% CI: 0.77, 0.91] vs 0.83 [95% CI: 0.75, 0.91], P = .90). Both had higher participant-based specificity than CCTA alone (54%, both P < .001) without evidence of a difference in sensitivity between CCTA (94%) and CCTA plus CT perfusion ( P = .50) or CCTA plus CT-FFR ( P = .63). The sequential approach combining CCTA plus CT-FFR with CT perfusion achieved higher participant-based specificity than CCTA plus CT-FFR (88% vs 77%, P = .03) without evidence of a difference in participant-based sensitivity (88% vs 90%, P > .99) and vessel-based AUC (0.85 [95% CI: 0.77, 0.93], P = .78). Compared with CCTA plus CT perfusion, the sequential approach showed no evidence of a difference in participant-based sensitivity ( P > .99), specificity ( P = .06), or vessel-based AUC ( P = .54). Conclusion There was no evidence of a difference in diagnostic accuracy between CCTA plus CT-FFR and CCTA plus CT perfusion for detecting hemodynamically relevant CAD. A sequential approach combining CCTA plus CT-FFR with CT perfusion led to improved participant-based specificity with no evidence of a difference in sensitivity compared with CCTA plus CT-FFR. ClinicalTrials.gov registration no.: NCT02810795 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Sinitsyn in this issue.

Inter-frame motion in dynamic cardiac positron emission tomography (PET) using rubidium-82 ( 82 Rb) myocardial perfusion imaging impacts myocardial blood flow (MBF) quantification and the diagnosis accuracy of coronary artery diseases. However, the high cross-frame distribution variation due to rapid tracer kinetics poses a considerable challenge for inter-frame motion correction, especially for early frames where intensity-based image registration techniques often fail. To address this issue, we propose a novel method called Temporally and Anatomically Informed Generative Adversarial Network (TAI-GAN) that utilizes an all-to-one mapping to convert early frames into those with tracer distribution similar to the last reference frame. The TAI-GAN consists of a feature-wise linear modulation layer that encodes channel-wise parameters generated from temporal information and rough cardiac segmentation masks with local shifts that serve as anatomical information. Our proposed method was evaluated on a clinical 82 Rb PET dataset, and the results show that our TAI-GAN can produce converted early frames with high image quality, comparable to the real reference frames. After TAI-GAN conversion, the motion estimation accuracy and subsequent myocardial blood flow (MBF) quantification with both conventional and deep learning-based motion correction methods were improved compared to using the original frames. The code is available at https://github.com/gxq1998/TAI-GAN., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)