A systematic review for the evidence of recommendations and guidelines in hybrid nuclear cardiovascular imaging.

OBJECTIVES: This study aimed to evaluate the level of evidence of expert recommendations and guidelines for clinical indications and procedurals in hybrid nuclear cardiovascular imaging. METHODS: From inception to August 2023, a PubMed literature analysis of the latest version of guidelines for clinical hybrid cardiovascular imaging techniques including SPECT(/CT), PET(/CT), and PET(/MRI) was performed in two categories: (1) for clinical indications for all-in primary diagnosis; subgroup in prognosis and therapy evaluation; and for (2) imaging procedurals. We surveyed to what degree these followed a standard methodology to collect the data and provide levels of evidence, and for which topic systematic review evidence was executed. RESULTS: A total of 76 guidelines, published between 2013 and 2023, were included. The evidence of guidelines was based on systematic reviews in 7.9% of cases, non-systematic reviews in 47.4% of cases, a mix of systematic and non-systematic reviews in 19.7%, and 25% of guidelines did not report any evidence. Search strategy was reported in 36.8% of cases. Strengths of recommendation were clearly reported in 25% of guidelines. The notion of external review was explicitly reported in 23.7% of cases. Finally, the support of a methodologist was reported in 11.8% of the included guidelines. CONCLUSION: The use of evidence procedures for developing for evidence-based cardiovascular hybrid imaging recommendations and guidelines is currently suboptimal, highlighting the need for more standardized methodological procedures.

Procedural recommendations of cardiac PET/CT imaging: standardization in inflammatory-, infective-, infiltrative-, and innervation (4Is)-related cardiovascular diseases: a joint collaboration of the EACVI and the EANM.

With this document, we provide a standard for PET/(diagnostic) CT imaging procedures in cardiovascular diseases that are inflammatory, infective, infiltrative, or associated with dysfunctional innervation (4Is). This standard should be applied in clinical practice and integrated in clinical (multicenter) trials for optimal procedural standardization. A major focus is put on procedures using [18F]FDG, but 4Is PET radiopharmaceuticals beyond [18F]FDG are also described in this document. Whilst these novel tracers are currently mainly applied in early clinical trials, some multicenter trials are underway and we foresee in the near future their use in clinical care and inclusion in the clinical guidelines. Finally, PET/MR applications in 4Is cardiovascular diseases are also briefly described. Diagnosis and management of 4Is-related cardiovascular diseases are generally complex and often require a multidisciplinary approach by a team of experts. The new standards described herein should be applied when using PET/CT and PET/MR, within a multimodality imaging framework both in clinical practice and in clinical trials for 4Is cardiovascular indications.

Position paper of the EACVI and EANM on artificial intelligence applications in multimodality cardiovascular imaging using SPECT/CT, PET/CT, and cardiac CT.

In daily clinical practice, clinicians integrate available data to ascertain the diagnostic and prognostic probability of a disease or clinical outcome for their patients. For patients with suspected or known cardiovascular disease, several anatomical and functional imaging techniques are commonly performed to aid this endeavor, including coronary computed tomography angiography (CCTA) and nuclear cardiology imaging. Continuous improvement in positron emission tomography (PET), single-photon emission computed tomography (SPECT), and CT hardware and software has resulted in improved diagnostic performance and wide implementation of these imaging techniques in daily clinical practice. However, the human ability to interpret, quantify, and integrate these data sets is limited. The identification of novel markers and application of machine learning (ML) algorithms, including deep learning (DL) to cardiovascular imaging techniques will further improve diagnosis and prognostication for patients with cardiovascular diseases. The goal of this position paper of the European Association of Nuclear Medicine (EANM) and the European Association of Cardiovascular Imaging (EACVI) is to provide an overview of the general concepts behind modern machine learning-based artificial intelligence, highlights currently prefered methods, practices, and computational models, and proposes new strategies to support the clinical application of ML in the field of cardiovascular imaging using nuclear cardiology (hybrid) and CT techniques.

Value of 12-lead electrocardiogram to predict myocardial scar on FDG PET in heart failure patients.

PURPOSE: A surface 12-lead electrocardiogram (ECG) is widely available, fast, inexpensive, and safe. However, its value to predict a true myocardial scar in patients with ischemic cardiomyopathy (ICM) has not been studied extensively yet. This study was conducted to assess whether Q waves on resting surface 12-lead ECG are predictive of non-viable myocardium in patients with ICM. METHODS: We analyzed resting ECGs of 149 patients with ICM undergoing cardiac positron emission tomography (PET) with 13N-ammonia (NH3) and 18F-fluorodeoxyglucose (FDG) at our institution. Pathological Q waves and QS complexes were assigned to one of three coronary artery territories and compared to the PET findings. Myocardial scar was defined as 2 or more contiguous myocardial segments with an average (matched) reduction of NH3 and FDG uptake <50% of the maximum value. RESULTS: Pathological Q waves had a sensitivity and specificity of 70% and 40%, respectively, and a PPV and NPV of 37% and 73%, respectively, to detect myocardial scar on FDG PET. For QS complexes, sensitivity and specificity were 46% and 59%, respectively, and PPV and NPV were 36% and 68%, respectively. Sensitivity was lower, but specificity was significantly higher in both the LCX and RCA compared to the LAD territory (p<0.001), particularly for QS complexes. CONCLUSION: Pathological Q waves on resting 12-lead ECG have poor or at best moderate sensitivity and specificity to detect myocardial scar on FDG PET. These findings support the use of more advanced imaging techniques to assess myocardial viability in ICM.

Sex and age differences in the association of heart rate responses to adenosine and myocardial ischemia in patients undergoing myocardial perfusion imaging.

BACKGROUND: In light of growing cardiovascular mortality rates observed in young women, sexual dimorphism in cardiac autonomic nervous control is gaining increasing attention. Heart rate responses to adenosine mirror autonomic activity and may carry important prognostic information. METHODS AND RESULTS: Hemodynamic changes during adenosine stress were retrospectively analysed in a propensity-matched cohort of 1932 consecutive patients undergoing myocardial perfusion single-photon-emission computed tomography (MPI-SPECT). Heart rate (HR) and systolic blood pressure (SBP) increased during adenosine infusion (P < 0.001). The increase in SBP and HR (heart rate reserve, HRR), was significantly more pronounced in women compared with men (P < 0.05). Patients ≤ 55 years had a higher HRR compared with patients > 55 years (46.8% vs 37.5%, P = 0.015). Women ≤ 55 years with a reversible perfusion defect on MPI-SPECT exhibited the highest HRR (89.2%), while age-matched men showed a blunted HR response to adenosine (26.4%, P = 0.01). Accordingly, age and an interaction term of female sex and increased HRR were identified as significant predictors of myocardial ischemia in a multiple regression analysis (OR 1.4, 95% CI 1.02-1.9, P = 0.038). CONCLUSION: HRR during adenosine infusion is influenced by age and sex. Our data suggest a stronger, sympathetic-driven, hemodynamic response to adenosine in younger women with myocardial ischemia.

Enhanced radiation exposure associated with anterior-posterior x-ray tube position in young women undergoing cardiac computed tomography.

Given the current increase in the incidence of coronary artery disease in younger women as well as the high lifetime risk of developing an x-ray-induced malignancy in this population, we aimed at assessing chest radiation in 206 women ≤55 years old undergoing coronary calcium scoring (CACS) by using a Monte Carlo simulation tool. Our data indicate that the simulated radiation dose of the female breast during CACS depends substantially on the starting position of the x-ray tube, with an almost 2 times excess of breast radiation exposure being measured during anterior-posterior tube positioning. Thus, an additional technical feature taking into account the position of the x-ray tube when acquisition is triggered might be an important tool to reduce radiation exposure of the female breast during CACS.

No differences in rest myocardial blood flow in stunned and hibernating myocardium: insights into the pathophysiology of ischemic cardiomyopathy.

PURPOSE: The human pathophysiology of stunned, hibernating and scarred myocardium in ischemic cardiomyopathy is a subject of controversy. While the "smart heart" theory postulates that reduced myocardial blood flow (MBF) at rest is responsible for myocytes switching to a state of hibernation, other theories suggest that a reduced myocardial flow reserve (MFR) may be the cause. METHODS: We included 110 patients with ischemic cardiomyopathy. Based on quantitative myocardial perfusion assessment and viability imaging with 13N-NH3 and 18F-FDG positron emission tomography, respectively, as well as wall motion assessment from echocardiography, myocardial tissue was characterized as remote (i.e., normal myocardium), stunned (i.e., dysfunctional but viable myocardium with normal rest perfusion), hibernating (i.e., dysfunctional but viable myocardium with impaired rest perfusion), or scarred myocardium (i.e., non-viable myocardium). RESULTS: Compared to remote myocardium, dysfunctional but viable myocardium (including stunned and hibernating) had reduced rest MBF (0.89 mL/min/g vs. 0.79 and 0.76 mL/min/g, respectively; p < 0.001) and MFR (1.53 vs. 1.27 and 1.17; p < 0.001). Between stunned and hibernating myocardium, however, rest MBF and MFR did not differ (p = 0.40). In scarred myocardium, rest MBF was lowest (0.66 mL/min/g; p < 0.001) but, in contrast to the other myocardial states, k2 (i.e., tracer washout) was increased (0.199/min vs. 0.178/min to 0.181/min; all p < 0.05 in pairwise comparison). CONCLUSIONS: In patients with ischemic cardiomyopathy, impaired MFR is associated with stunning and hibernation. These states of dysfunctional but viable myocardium have lower rest MBF compared to remote myocardium. At the end of the continuum, rest MBF is lowest in scar tissue and linked to increased rate of tracer washout.

Multimodality imaging: Bird's eye view from The European Society of Cardiology Congress 2018 Munich, August 25-29, 2018.

At the European Society of Cardiology (ESC) congress of this year 2018, held in Munich from August 25th to 29th, 4594 abstracts were presented. Of those, 423 (10.8%) belonged to an imaging category. Experts in echocardiography (VD), cardiovascular magnetic resonance (CMR) (CBD), nuclear imaging (OG), and cardiac computed tomography (CT) (PMH) have selected the abstracts in their areas of expertise that were of most interest to them and are summarized in this bird's eye view from this ESC meeting. These abstracts were integrated by one of the Editors of the Journal (JB).

Gated SPECT myocardial perfusion imaging with cadmium-zinc-telluride detectors allows real-time assessment of dobutamine-stress-induced wall motion abnormalities.

BACKGROUND: Left ventricular (LV) ejection fraction (EF) during high dobutamine stress (HD) by real-time gated-SPECT myocardial perfusion imaging (MPI) on a cadmium-zinc-telluride (CZT) gamma camera was validated versus cardiac magnetic resonance imaging (CMR). METHODS AND RESULTS: After injecting 99mTc-tetrofosmin (320 MBq) in 50 patients (mean age 64 +/- 11 years), EF at rest and post-stress as well as relevant changes in EF at HD (ΔEF ≥ 5%) were assessed. CZT and CMR rest EF values yielded an excellent correlation and agreement (r = 0.96; P < 0.001; Bland-Altman limits of agreement (BA): + 0 to 14.8%). HD EF acquisition was feasible using CZT and correlated better to HD CMR EF than did post-stress CZT EF (r = 0.85 vs 0.76, respectively, all P < 0.001). Agreement in ΔEF detection between HD CMR and immediate post-stress CZT (reflecting standard acquisition using conventional SPECT camera unable to scan during stress) was 45%, while this increased to 85% with real-time HD CZT scan. CONCLUSION: Real-time ultrafast dobutamine gated-SPECT MPI with a CZT device is feasible and provides accurate measurements of HD LV performance.

Corrected coronary opacification decrease from coronary computed tomography angiography: Validation with quantitative 13N-ammonia positron emission tomography.

BACKGROUND: To assess the functional relevance of a coronary artery stenosis, corrected coronary opacification (CCO) decrease derived from coronary computed tomography angiography (CCTA) has been proposed. The present study aims at validating CCO decrease with quantitative 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI). METHODS AND RESULTS: This retrospective study consists of 39 patients who underwent hybrid CCTA/PET-MPI. From CCTA, attenuation in the coronary lumen was measured before and after a stenosis and corrected to the aorta to calculate CCO and its decrease. Relative flow reserve (RFR) was calculated by dividing the stress myocardial blood flow (MBF) of a vessel territory subtended by a stenotic coronary by the stress MBF of the reference territories without stenoses. RFR was abnormal in 11 vessel territories (27%). CCO decrease yielded a sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for prediction of an abnormal RFR of 73%, 70%, 88%, 47%, and 70%, respectively. CONCLUSIONS: CCTA-derived CCO decrease has moderate diagnostic accuracy to predict an abnormal RFR in PET-MPI. However, its high negative predictive value to rule out functional relevance of a given lesion may confer clinical implications in the diagnostic work-up of patients with a coronary stenosis.

Coronary computed tomography angiography for heart team decision-making in multivessel coronary artery disease.

Aims: Coronary computed tomography angiography (CTA) has emerged as a non-invasive diagnostic method for patients with suspected coronary artery disease, but its usefulness in patients with complex coronary artery disease remains to be investigated. The present study sought to determine the agreement between separate heart teams on treatment decision-making based on either coronary CTA or conventional angiography. Methods and results: Separate heart teams composed of an interventional cardiologist, a cardiac surgeon, and a radiologist were randomized to assess the coronary artery disease with either coronary CTA or conventional angiography in patients with de novo left main or three-vessel coronary artery disease. Each heart team, blinded for the other imaging modality, quantified the anatomical complexity using the SYNTAX score and integrated clinical information using the SYNTAX Score II to provide a treatment recommendations based on mortality prediction at 4 years: coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or equipoise between CABG and PCI. The primary endpoint was the agreement between heart teams on the revascularization strategy. The secondary endpoint was the impact of fractional flow reserve derived from coronary CTA (FFRCT) on treatment decision and procedural planning. Overall, 223 patients were included. A treatment recommendation of CABG was made in 28% of the cases with coronary CTA and in 26% with conventional angiography. The agreement concerning treatment decision between coronary CTA and conventional angiography was high (Cohen's kappa 0.82, 95% confidence interval 0.74-0.91). The heart teams agreed on the coronary segments to be revascularized in 80% of the cases. FFRCT was available for 869/1108 lesions (196/223 patients). Fractional flow reserve derived from coronary CTA changed the treatment decision in 7% of the patients. Conclusion: In patients with left main or three-vessel coronary artery disease, a heart team treatment decision-making based on coronary CTA showed high agreement with the decision derived from conventional coronary angiography suggesting the potential feasibility of a treatment decision-making and planning based solely on this non-invasive imaging modality and clinical information. Trial registration number: NCT02813473.

Hybrid SPECT Perfusion Imaging and Coronary CT Angiography: Long-term Prognostic Value for Cardiovascular Outcomes.

Purpose To determine the value of cardiac hybrid imaging, performed by combining SPECT myocardial perfusion imaging (MPI) with coronary CT angiography, as a long-term predictor for major adverse cardiac events (MACEs) (death, myocardial infarction [MI], unstable angina requiring hospitalization, coronary revascularization). Materials and Methods For this retrospective single-center study, 428 patients referred between May 2005 and December 2008 were classified according to hybrid imaging findings into the following groups: (a) those with stenosis of 50% or greater (at coronary CT angiography) with ischemia (at SPECT) in subtended territory (matched), (b) those with coronary CT angiography and/or SPECT findings in unrelated territories (unmatched), and (c) those with normal findings at coronary CT angiography and SPECT. End points were all-cause death or MI ("hard events") and a composite of MACEs. The Kaplan-Meier method was used to identify survival free of MACEs, and Cox proportional hazard regression analysis was used to determine independent predictors for MACE. Results During a median follow-up of 6.8 years, a total of 160 MACEs, including 45 deaths, were observed in the final study population (mean age, 62 years ± 11 [standard deviation]; 132 women). The annual hard event rate was more than fivefold higher for patients with matched findings (n = 46 [7.0%]) and was threefold higher for patients with unmatched findings (n = 113 [3.7%]) compared with that for patients with normal findings (1.2%; n = 216 [1.2%]; P < .001). The MACE rates were 21.8%, 9.0%, and 2.4% for matched, unmatched, and normal findings, respectively. A matched finding was an independent predictor for MACE and hard events. Conclusion In patients evaluated for coronary artery disease, cardiac hybrid imaging is an excellent long-term predictor of adverse cardiac events. A matched hybrid finding is associated with a high annual cardiac event rate. © RSNA, 2018.

Recommendations on nuclear and multimodality imaging in IE and CIED infections.

In the latest update of the European Society of Cardiology (ESC) guidelines for the management of infective endocarditis (IE), imaging is positioned at the centre of the diagnostic work-up so that an early and accurate diagnosis can be reached. Besides echocardiography, contrast-enhanced CT (ce-CT), radiolabelled leucocyte (white blood cell, WBC) SPECT/CT and [18F]FDG PET/CT are included as diagnostic tools in the diagnostic flow chart for IE. Following the clinical guidelines that provided a straightforward message on the role of multimodality imaging, we believe that it is highly relevant to produce specific recommendations on nuclear multimodality imaging in IE and cardiac implantable electronic device infections. In these procedural recommendations we therefore describe in detail the technical and practical aspects of WBC SPECT/CT and [18F]FDG PET/CT, including ce-CT acquisition protocols. We also discuss the advantages and limitations of each procedure, specific pitfalls when interpreting images, and the most important results from the literature, and also provide recommendations on the appropriate use of multimodality imaging.

Percutaneous pulmonary valve implantation in grown-up congenital heart disease patients: Insights from the Zurich experience.

OBJECTIVES: The aim of the study was to assess indications, procedural success, complications, echocardiographic, and clinical outcomes of percutaneous pulmonary valve implantation (PPVI) in adult patients with congenital heart disease (CHD). BACKGROUND: PPVI offers a non-surgical treatment option for failing prosthetic conduits in pulmonary position. However, efficacy and clinical outcomes after PPVI are still underreported. METHODS: From January 2008 to March 2016, 25 adult CHD patients with right ventricular outflow tract (RVOT) stenosis and/or pulmonary regurgitation underwent PPVI in our institution. Clinical and echocardiographic data was collected at baseline, at 12 months of follow-up and yearly afterwards. RESULTS: Tetralogy of Fallot and repaired pulmonary atresia were among the most prevalent underlying congenital defects. Twenty-one (84%) received a Medtronic Melody® and four (16%) patients an Edwards Sapien valve prosthesis. The PPVI procedure was successful in all 25 patients. Pre-stenting was performed in all but two (8%) patients. PPVI reduced peak-to-peak pulmonary valve gradient from 43 (IQR 28-60) mmHg to 16 (IQR 14-22) mmHg (P < 0.001). Periprocedural complications occurred in two (8%) patients (tricuspid valve damage, pulmonary artery perforation). Over a median follow-up of 43 (IQR 18-58) months all patients were alive. Only two (8%) required re-operation and two (8%) developed stent fractures (one of them had not undergone pre-stenting). NYHA functional class improved significantly, with 20 (80%) patients in NYHA class I on follow-up. CONCLUSIONS: PPVI with Medtronic Melody or Edwards Sapien valve conduits is safe and provides effective relief from right ventricular outflow tract obstruction or pulmonary regurgitation.

Sports Behavior in Middle-Aged Individuals with Anomalous Coronary Artery from the Opposite Sinus of Valsalva.

OBJECTIVES: Recommendations regarding sports restriction are lacking for middle-aged athletes with anomalous coronary arteries originating from the opposite sinus of Valsalva (ACAOS). METHODS: Sixty-three patients with ACAOS were subdivided into ACAOS with (n = 38) or without (n = 25) an interarterial course (IAC). Sports behavior, either competitive (COMP) or recreational (REC), was evaluated at the time of diagnosis and after a median follow-up of 4.2 years. RESULTS: Mean age was 56 ± 11 years and 48 (76.2%) patients were engaged in sports. Three individuals (4.8%) were surgically corrected after diagnosis. Thirty-eight (60.3%) patients were aware of their diagnosis at follow-up and 12 (19.0%) were counseled by their physician about sports restrictions. Sports behavior at the time of diagnosis and at follow-up did not differ significantly, neither in patients engaged in COMP (17.5 vs. 12.7%, p = 0.619) nor those engaged in REC (58.7 vs. 61.9%, p = 0.856). Sport-related symptoms were not significantly different between ACAOS patients with and without IAC. No athlete had died at follow-up. CONCLUSIONS: The majority of middle-aged individuals with ACAOS were involved in sports activities at the time of diagnosis and at follow-up. Awareness and counseling about ACAOS diagnosis had no significant effect on sports behavior. IAC did not have an impact on sport-related symptoms, and outcomes were favorable in all athletes, regardless of surgical correction.

Outcome in middle-aged individuals with anomalous origin of the coronary artery from the opposite sinus: a matched cohort study.

AIMS: Anomalous origin of a coronary artery from the opposite sinus (ACAOS) has been associated with adverse cardiac events in the young. It remains unknown whether this holds true for middle-aged patients with uncorrected ACAOS as well. We assessed the outcome in middle-aged patients with newly diagnosed ACAOS by coronary computed tomography angiography (CCTA) compared with a matched cohort. METHODS AND RESULTS: We retrospectively identified 68 consecutive patients with ACAOS documented by CCTA. ACAOS with a course of the anomalous vessel between the aorta and pulmonary artery were classified as interarterial course (IAC). Each patient with ACAOS was matched to two controls without ACAOS. Major adverse cardiac events (i.e. myocardial infarction, revascularization and cardiac death) were recorded for all patients and controls. Two (3%) patients were lost to follow-up. Thus, 66 patients with ACAOS were included in the final analysis and matched with 132 controls. Mean age of patients was 56 ± 11 years, 73% were male and the mean follow-up was 49 months. Forty (65%) patients were classified as having ACAOS with IAC. The annual event rate of ACAOS vs. controls was 4.9 and 4.8%, the hazard ratio (HR) 0.94 (0.39-2.28, P = 0.89). The annual event rate of ACAOS with IAC compared with their matched controls was 5.2 and 4.3%, and the HR 1.01 (95% CI 0.39-2.58, P = 0.99). CONCLUSIONS: In middle-aged individuals with newly diagnosed ACAOS mid-term outcome is not statistically different to a matched control cohort without coronary artery anomalies, regardless of whether ACAOS with or without IAC variants are present.

Intracardiac versus transesophageal echocardiography for left atrial appendage occlusion with watchman.

BACKGROUND: Left atrial appendage occlusion (LAAO) is mostly performed by transesophageal echocardiography (TEE) guidance. Intracardiac echocardiography (ICE) may be an alternative imaging modality for LAAO that precludes the need for general anesthesia or sedation. METHODS AND RESULTS: All consecutive single center, single operator LAAO candidates were analyzed. Baseline clinical and procedural characteristics and in-hospital outcomes were compared between patients in whom a Watchman was implanted with ICE vs. TEE guidance. In 76 consecutive patients the Watchman device was deployed under ICE in 32 patients (42%) and under TEE guidance in 44 patients (58%). Baseline characteristics were comparable between groups, except that patients in the TEE group were older (81 [75-85] years vs. 75 [68-80] years, P = 0.007). Total injected contrast media as well as fluoroscopy time were comparable between groups (90 ml [54-140] vs. 85 ml [80-110], P = 0.86 and 7.9 min [6.4-15.5] vs. 9.8 min [7.0-13.2], P = 0.51, for TEE vs. ICE, respectively). However, time from femoral venous puncture to transseptal puncture and to closure was longer in the ICE group (14 min [7.3-20] vs. 6 min [3.3-11], P = 0.007 and 48 min [40-60] vs. 34.5 min [27-44], P = 0.003, respectively). In the TEE group one patient suffered esophageal erosion with bleeding, which was managed conservatively and one non-LAAO related in-hospital mortality occurred in an 88-year-old patient. Device implantation success rate was 100% in both groups. No device embolization, no significant peri-device leak, no tamponade, no stroke, and no access site bleeding occurred in any patient. Total hospital stay for stand-alone LAAO was comparable between groups (2 days [2-2] vs. 2 days [2-3.3], P = 0.17, in ICE vs. TEE, respectively). CONCLUSIONS: ICE guidance for LAAO with the Watchman device is feasible and comparable to TEE and may become the preferred imaging modality for LAAO. © 2016 Wiley Periodicals, Inc.