J Nucl Cardiol
· 2025 Sep · PMID 40623659
·
Full text
Total-body positron emission tomography (PET) is an emerging tool whose potential is being actively explored to interrogate multisystem biologic processes. Cardiovascular-kidney-metabolic (CKM) syndrome is increasingly r...Total-body positron emission tomography (PET) is an emerging tool whose potential is being actively explored to interrogate multisystem biologic processes. Cardiovascular-kidney-metabolic (CKM) syndrome is increasingly recognized as a multidimensional disease driving cardiovascular and renal morbidity and mortality, but the underlying pathologic mechanisms remain incompletely understood. As mechanistic investigation moves to understand systems physiology in CKM syndrome, the ability to simultaneously assess shared biologic processes and crosstalk between the cardiovascular and renal systems is a unique strength of total-body PET. Total-body PET-computed tomography (PET-CT) systems can leverage existing and novel radiotracers to evaluate perfusion, fibrosis, metabolism, inflammation, and body composition. This review summarizes evidence for the assessment of cardiovascular and renal tissues with PET and discusses potential future applications for understanding mechanistic interactions between these interrelated systems using total-body PET, which could ultimately be applied to the development of targeted therapies for the benefit of patients with CKM disorders.
This document from the American Society of Nuclear Cardiology develops metrics for the assessment of quality for laboratories that perform cardiac amyloid radionuclide imaging. These metrics are based on clinical guideli...This document from the American Society of Nuclear Cardiology develops metrics for the assessment of quality for laboratories that perform cardiac amyloid radionuclide imaging. These metrics are based on clinical guidelines, appropriate use criteria, information and position statements, and expert opinion. The document introduces 15 quality metrics that address current gaps in care organized around 4 axes: A) Appropriate indications; B) Patient experience and workflow; C) Instrumentation and protocols; and D) Interpretation and reporting. With the increasing use of imaging for cardiac amyloid, it is imperative that our laboratories maintain a high level of quality to preserve the value that imaging provides to patients. Laboratories should perform imaging in appropriately selected patients avoiding low-value imaging. Proper education should be provided to patients prior to performing testing, timely access to testing must be available, and periodic assessment of patient experience and satisfaction should be the norm. Strict adherence to established protocols with periodic assessment of laboratory quality control is essential. Laboratory studies to rule out plasma cell dyscrasia should be performed in all patients suspected of having cardiac amyloidosis. Crucially, interpretation should be based on SPECT rather than planar imaging in all patients. The study report should include sufficient technical details to allow for proper interpretation of study findings and its conclusion should be clear and unambiguous to guide clinical management. Laboratories can use data derived from these metrics to identify areas of deficiency and introduce quality improvement initiatives, which will ultimately improve patient outcomes.
BACKGROUND: Myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurement is crucial for diagnosing and managing coronary artery disease and microvascular dysfunction. While positron emission tomography (PET)...BACKGROUND: Myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurement is crucial for diagnosing and managing coronary artery disease and microvascular dysfunction. While positron emission tomography (PET) is the gold standard, cadmium zinc telluride (CZT) is more accessible. This systematic review and meta-analysis aim to compare the accuracy, and the systematic bias of MBF and MFR measurement using CZT compared with PET. METHODS: We conducted a systematic review across multiple databases up to April 2024. The main outcomes were mean difference between MBF and MFR values obtained from PET and CZT, limits of agreement, and diagnostic performance. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool and statistical analysis was conducted using random effects models. RESULTS: Eight studies, encompassing 268 patients, met the inclusion criteria. The mean difference for rest and stress myocardial blood flow between PET and CZT was .006 (95% confidence interval [CI]: -.088, .100) and .111 (95% CI: -.418, .195), respectively. The myocardial flow reserve mean difference was .0178 (95% CI: -.492, .135). Bland-Altman meta-analysis demonstrated a bias of .05 mL/min/g (95%CI: -1.08 to 1.24) for rest MBF, .13 mL/min/g for stress MBF (95%CI: -.969 to 1.228), and .03 mL/min/g (95%CI: -.999, 1.006) bias for MFR. The diagnostic performance for detecting significant reductions in MBF and MFR on single-photon emission computed tomography using PET as the gold standard demonstrated sensitivity and specificity of 80.8% and 87.0%, respectively. CONCLUSIONS: CZT MBF measurements demonstrated good agreement with PET, although they had a slight underestimation. While PET remains the preferred modality due to its superior performance, CZT represents a viable alternative when PET is unavailable. Future research should focus on standardizing CZT protocols.
PURPOSE: To assess the diagnostic performance of F-flupiridaz positron emission tomography (PET) myocardial perfusion imaging (MPI) for coronary artery disease detection using total perfusion deficit (TPD), an automated...PURPOSE: To assess the diagnostic performance of F-flupiridaz positron emission tomography (PET) myocardial perfusion imaging (MPI) for coronary artery disease detection using total perfusion deficit (TPD), an automated metric of combined disease extent and severity. METHODS: Flurpiridaz relative perfusion images and quantitative coronary angiography data from the initial phase III trial were evaluated using receiver operating characteristic analysis at separate endpoints of ≥70% stenosis and ≥50% stenosis, to determine the diagnostic performance of TPD at per-patient (global LV) and per-vessel levels. TPD results at both endpoints were compared with the performance of visual scores and defect extent values available from two previous publications. RESULTS: Using a normal perfusion database that was created with the data of 25 patients from the flurpiridaz trial population, TPD was calculated in the remaining 729 trial patients. At the threshold of ≥70% stenosis, TPD was observed to have similar (P ≥ .05) per-patient diagnostic performance (74% accuracy) to visual scoring from previous publications (75%, 71%), as well as defect extent (72%). At the per-vessel level, the TPD achieved similar performance to defect extent in the left anterior descending artery (LAD) and left circumflex artery (LCx) (79%, 74% vs 80%, 72% accuracy) with slightly higher accuracy in the right coronary artery (RCA) (77% vs 72%, P = .03), and similar performance to visual scoring in the LAD and RCA (77, 79% vs 76%, 76% accuracy) with marginally lower performance in the LCx (74% vs 79%, P = .03). Similar results were observed at the ≥50% obstructive disease endpoint. CONCLUSIONS: Automated TPD demonstrated similar diagnostic performance for global and regional flurpiridaz PET MPI, respectively, to visual scoring and defect extent quantification.
BACKGROUND: Diagnosing transthyretin-related cardiac amyloidosis (ATTR-CA) relies on excluding plasma cell dyscrasia and performing bone-avid tracer cardiac scintigraphy. However, visual assessment of cardiac uptake has...BACKGROUND: Diagnosing transthyretin-related cardiac amyloidosis (ATTR-CA) relies on excluding plasma cell dyscrasia and performing bone-avid tracer cardiac scintigraphy. However, visual assessment of cardiac uptake has limitations in evaluating amyloid burden. Whole-body single-photon emission computed tomography-computed tomography (SPECT-CT) may overcome these limitations by enabling quantitative assessment, but data on test-retest reproducibility are lacking. OBJECTIVES: This study aimed to evaluate the test-retest, intraobserver and interobserver reproducibility of cardiac amyloid quantification in suspected ATTR-CA using whole-body cadmium zinc telluride SPECT-CT. METHODS: Twenty patients with suspected ATTR-CA underwent repeated planar bone-avid tracer cardiac scintigraphy and thoracic SPECT-CT one week apart (October 2020-December 2022; Clinical Trial: NCT04535349). The Perugini score was assessed using planar acquisition. Cardiac 99mTc-HMDP uptake was quantified on SPECT images with CT-based cardiac contouring and attenuation correction. The evaluated metrics included maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), percentage of injected dose (%ID), and cardiac amyloid activity (CAA). Concordance was evaluated by Lin's concordance correlation coefficient (CCC). Test-retest reproducibility was assessed using the mean absolute difference, coefficient of variation, and intraclass correlation coefficient (ICC). RESULTS: Intraobserver and interobserver reproducibility was excellent for all metrics (CCC ≥.99). Test-retest reproducibility demonstrated substantial agreement for SUVmean (CCC: .79) and almost perfect agreement for SUVmax (CCC: .81), %ID (CCC: .88), and CAA (CCC: .93). All parameters correlated with the Perugini score. Test-retest reliability was high across metrics, with ICC values of .80-.97. CONCLUSIONS: Bone-avid tracer cardiac SPECT-CT shows excellent reproducibility for quantifying cardiac amyloid burden in suspected ATTR-CA, with %ID and CAA being especially reliable for future longitudinal studies. CLINICAL TRIAL REGISTRATION: NCT04535349.
Romero Pabón AJ, Clerc OF, Cuddy SAM
… +6 more, Vijayakumar S, Lan Z, Gaggin HK, Di Carli MF, Falk RH, Dorbala S
J Nucl Cardiol
· 2025 Sep · PMID 40518107
·
Full text
BACKGROUND: The aim of our study was to evaluate the prognostic value of amyloid burden estimated by technetium-pyrophosphate single-photon emission computed tomography (Tc-PYP-SPECT) visual grade in patients with transt...BACKGROUND: The aim of our study was to evaluate the prognostic value of amyloid burden estimated by technetium-pyrophosphate single-photon emission computed tomography (Tc-PYP-SPECT) visual grade in patients with transthyretin (ATTR) amyloid cardiomyopathy (ATTR-CM) receiving TTR stabilization therapy. METHODS: Our retrospective cohort study included 344 ATTR-CM participants receiving TTR stabilization therapy. Tc-PYP-SPECT myocardial uptake was graded as 0, 1, 2, or 3, based on myocardial uptake that was absent, less than, equal to, or greater than rib uptake, respectively. National Amyloidosis Center (NAC) stage was defined by N-terminal pro B-type natriuretic peptide (≤3000 pg/mL) and estimated glomerular filtration rate (≥45 mL/min/1.73 m) levels. The primary outcome was all-cause mortality. Kaplan-Meier survival and multivariable Cox regression analyses were performed. RESULTS: Of the 344 participants (median age: 80 years), 88% were men and 98% had a Tc-PYP-SPECT visual grade uptake of 2 or 3. Seventy-six participants (22.1%) died during follow-up (median: 27 months). In the Cox regression analysis adjusted for age, NAC stage, New York Heart Association (NYHA) class, left ventricular (LV) mass index, LV ejection fraction, and Tc-PYP-SPECT visual grade, only NAC stage (hazard ratio [HR]: 4.01, P value <.001) and NYHA class (HR: 5.22, P value = .011) strongly predicted mortality. CONCLUSIONS: In patients with ATTR-CM receiving TTR stabilization therapy, organ dysfunctions evidenced by NAC stage and NYHA class, but not by amyloid burden on Tc-PYP-SPECT visual grade, are strong predictors of mortality. Our results support a revision to Tc-PYP visual grading 2 and 3 into a single grade (positive). Future work is needed to evaluate whether amyloid burden measured by quantitative Tc-PYP-SPECT offers prognostic value in ATTR-CM.
BACKGROUND: While the rate of ischemia on stress myocardial perfusion imaging (MPI) has decreased over the last two decades, many symptomatic patients remain at an intermediate to high risk for cardiac events. Exercise w...BACKGROUND: While the rate of ischemia on stress myocardial perfusion imaging (MPI) has decreased over the last two decades, many symptomatic patients remain at an intermediate to high risk for cardiac events. Exercise workload, heart rate (HR) response, HR recovery, hemodynamic gain index, and blood pressure response to exercise have established prognostic value in isolation; however, the utility of these markers in patients with normal myocardial perfusion and no ischemic electrocardiogram ST segment depression (normal stress MPI) is unknown. METHODS: We performed a retrospective, single-center analysis of abnormal stress exercise markers in 892 patients who had a normal stress MPI from 2015 to 2017. We measured the prevalence and relative risk for death or non-fatal myocardial infarction associated with additive abnormal stress exercise markers. RESULTS: The mean age of patients was 61 years (55% male). Most patients (82.6%) had possible cardiac symptoms. At least one abnormal marker was found in 65.1% patients, and 9.6% had three or more markers. After adjustment for traditional risk factors, there was a 36% stepwise increase in the risk for events with each additional marker present, and patients with three or more markers were at the highest risk for events (HR: 2.44 [1.09-5.48], P = .031). CONCLUSIONS: Patients with normal stress MPI have a high burden of abnormal stress exercise markers, which confer a stepwise increase in the risk for adverse events. This prognostic information highlights an added value of exercise testing for risk stratification in patients with normal stress MPI and may suggest symptom etiology in the absence of ischemia.