Myocardial Perfusion Imaging Research Articles

The Prognostic Interplay of Coronary Artery Calcium Volume and Density with Myocardial Flow Reserve and Incident Cardiovascular Events.

It is important to evaluate the relationship between coronary plaque characteristics and myocardial blood flow (MBF) to determine coronary phenotypes that may predispose to cardiovascular disease. To study the association between coronary artery calcium (CAC) volume and density and positron emission tomography (PET)-derived myocardial flow reserve (MFR) and their relationship with incident cardiovascular disease. The study population consisted of consecutive patients who were referred for clinically indicated PET myocardial perfusion imaging between 2019 and 2024. CAC was assessed in a separate gated scan done just prior to PET and calculated using the Agatston score. Since the Agatston score includes calcified plaques (≥130 HU), soft and low-density plaques were not assessed. MFR was calculated as the ratio of stress to rest MBF. Patients with CAC=0 and those with known CAD were excluded. The study population consisted of 3,884 individuals with mean (SD) age 69 (±10.5) years. When CAC volume and density were included in the same model, CAC density was positively associated with MFR (β coefficient= 0.10, 95% CI 0.06, 0.15) and CAC volume was inversely associated (β coefficient -0.08, 95% CI -0.10, -0.05). During a median follow-up of 13.7 months, the primary outcome (death/myocardial infarction) occurred in 218 individuals (5.6%). When CAC volume and density were included in the same model including demographics and cardiovascular risk factors, CAC density was inversely and significantly associated with the primary outcome (HR= 0.67, 95% CI 0.47, 0.96) while CAC volume was positively and significantly associated with it (HR= 1.57, 95% CI 1.34, 1.82). Results were no longer significant after further adjustment for CAC, stress test parameters and MFR. At any level of CAC volume, higher CAC density is significantly associated with higher MFR but not associated with risk of death/myocardial infarction.

A Multi-Modality Attention Network for Coronary Artery Disease Evaluation From Routine Myocardial Perfusion Imaging and Clinical Data.

Myocardial perfusion imaging (MPI) is an essential tool for diagnosing and evaluating coronary artery disease (CAD). However, the diagnosis using MPI remains laborious as it involves multi-step readouts and meticulous image processing. These challenges impact current attempts at automating image interpretation of MPI. In this paper, we propose a multi-modality attention network (MMAN) that leverages information from clinical and MPI data for CAD diagnosis. Specifically, we propose an image-correlated cross-attention (ICCA) module that fuses information from both stress and rest MPI to enhance feature representation at the image level. Furthermore, we design a clinical data-guided attention (CDGA) module that integrates clinical data with image features to improve overall feature understanding for CAD evaluation. In addition, we employ self-learning for network pre-training, which further enhances the diagnostic performance using MPI on CAD. Experiments on a myocardial perfusion imaging dataset demonstrate that the proposed method is effective for CAD evaluation using myocardial perfusion imaging and clinical data.

Association of Medical Therapies with Survival According to SPECT MPI Findings.

Association of Medical Therapies with Survival According to SPECT MPI Findings.

A Myocardial Reorientation Method based on Feature Point Detection for Quantitative Analysis of PET Myocardial Perfusion Imaging

A Myocardial Reorientation Method based on Feature Point Detection for Quantitative Analysis of PET Myocardial Perfusion Imaging

MD Eccentricity index as an adjunctive indicator of coronary ischemia: Correlation with ischemic burden based on myocardial perfusion imaging

BACKGROUND: One of the main challenges in managing CAD is the measurement of ischemic burden experienced by patients, which can influence therapy decisions and prognosis. The Left Ventricular Eccentricity Index (EI) has become a potential additional indicator for assessing the severity of ischemia in CAD patients. OBJECTIVES: This study aims to analyze the correlation between the Left Ventricular EI and ischemic burden measured using myocardial perfusion imaging (MPI) in CAD patients. METHODS: This retrospective cohort study was conducted at Dr. Hasan Sadikin Hospital in Bandung from August 2023 to June 2024. Data were collected using MPI with 99mTc sestamibi gated SPECT. Statistical analysis was performed using the Mann-Whitney U test and Spearman's correlation. RESULTS: A total of 78 patients who met the inclusion and exclusion criteria were included in this study. The analysis showed that EI values in both the stress and rest phases were significantly higher in the group with ischemic burden ≥10%. The median ejection fraction value in the stress phase was also lower in this group (p = 0.013). Correlation analysis revealed a significant relationship between EI and ischemic burden (p < 0.05). CONCLUSION: This study demonstrates that EI can be used as an additional indicator to assess the severity of ischemia in CAD patients. Integrating EI into routine MPI protocols can improve the accuracy of risk stratification and management of CAD patients.

Prognostic value of myocardial perfusion imaging in asymptomatic high-risk diabetic patients: 10-year follow-up of the prospective multicentre BARDOT trial.

Patients with type 2 diabetes mellitus (T2DM) are at high risk for coronary artery disease (CAD) related events and are often asymptomatic. The role of cardiac imaging in screening asymptomatic T2DM patients remains controversial, as existing studies are limited by short follow-up periods. Therefore, study aim was to provide long-term (10 years) outcome data of T2DM patients screened with cardiac imaging. A total of 400 asymptomatic, high-risk T2DM patients without history of CAD underwent screening with Single Photon Emission Computed Tomography (SPECT). Abnormal SPECT was defined as Summed Stress Score ≥ 4 or Summed Difference Score ≥ 2. Patients were followed for all-cause mortality and major adverse cardiovascular events (MACE = cardiovascular mortality + myocardial infarction).The mean age was 63±8 years; 69% were male. Diabetic end-organ damage was present in 87% of patients. Baseline SPECT was abnormal in 22% of patients. Median follow-up was 11.1 [8.8, 12.8] years. Abnormal SPECT was associated with higher all-cause mortality (HR 1.614, p = 0.029) and MACE (HR 2.024, p = 0.009). A normal SPECT was associated with a significantly better prognosis (all-cause mortality 1.9% vs. 3.1%/year, p = 0.016; MACE 1.2% vs. 2.3%/year, p = 0.010). In the small subgroup of patients with abnormal SPECT, the treatment strategy (revascularization vs. conservative) had no effect on event-free survival. A normal SPECT was associated with an excellent long-term prognosis in high-risk T2DM patients. Hence, SPECT could serve as a valuable tool for advanced risk stratification in this population.

Plaque burden improves the detection of ischemic CAD over stenosis from coronary computed tomography angiography.

In symptomatic patients undergoing coronary CTA for suspected coronary artery disease (CAD), we assessed if quantification of plaque burden, in addition to luminal narrowing and clinical risk factors, offers incremental value for the identification of ischemic CAD on a per patient level. We evaluated 2145 patients who underwent coronary CTA for suspected CAD with sequential selective downstream 15O-water positron emission tomography (PET) myocardial perfusion imaging. Coronary CTA scans were analyzed using Artificial Intelligence-guided Quantitative Computed Tomography (AI-QCT), with measurement of maximum diameter stenosis, percent atheroma volume (PAV), percent calcified plaque volume (CPV) and percent noncalcified plaque volume (NCPV). Ischemic CAD was defined as the presence of abnormal stress perfusion on 15O-water PET. PAV on top of the clinical variables and ≥ 50% stenosis improved the prediction of ischemic CAD on a per patient level as compared to clinical variables and ≥ 50% stenosis (AUC = 0.91 vs. AUC = 0.87, p < 0.001). The best diagnostic performance was achieved when PAV with a cut-off value of 12.2% was applied in patients with intermediate (30-70%) stenosis; using this approach, the sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for ischemic CAD were 76%, 91%, 64%, 95% and 88%. The addition of quantitative plaque volume on top of clinical variables and ≥ 50% diameter stenosis improves the detection of ischemic CAD as defined by PET perfusion imaging. Applying a PAV threshold of 12.2% in patients with intermediate stenosis provided the best diagnostic performance.

High-Sensitivity Troponin Elevation in a Young Woman with Typical Chest Pain: The Heart of the Matter.

In the era of high-sensitivity troponin, minor elevations are often attributed to noncardiac etiologies. However, in patients who present with characteristic symptoms, any troponin elevation is concerning. We detail a case of a 37-y-old woman who presented to an outside hospital with typical chest pain and had a mild elevation in high-sensitivity troponin. Given her overall stability, she was discharged with outpatient cardiology follow-up. 82Rb PET/CT myocardial perfusion imaging test demonstrated a large, reversible anteroseptal perfusion defect. Coronary angiography revealed severe (80%) stenosis in the proximal left anterior descending artery treated with a single stent. This case highlights the need to have a high index of suspicion in young people with minor troponin elevations and pursue timely imaging.

3D motion corrected free-breathing SMS-bSSFP myocardium perfusion imaging.

3D motion corrected free-breathing SMS-bSSFP myocardium perfusion imaging.

Patient Centric Performance and Interpretation of SPECT and SPECT/CT Myocardial Perfusion Imaging. A Clinical Consensus Statement of the European Association of Cardiovascular Imaging of the ESC

Patient Centric Performance and Interpretation of SPECT and SPECT/CT Myocardial Perfusion Imaging. A Clinical Consensus Statement of the European Association of Cardiovascular Imaging of the ESC

Can interactive artificial intelligence be used for patient explanations of nuclear medicine examinations in Japanese?

This study aimed to evaluate the accuracy and validity of patient explanations about nuclear medicine examinations generated in Japanese using ChatGPT- 3.5 and ChatGPT- 4. ChatGPT was used to generate Japanese language explanations for seven single-photon emission computed tomography examinations (bone scintigraphy, brain perfusion imaging, myocardial perfusion imaging, dopamine transporter scintigraphy [DAT scintigraphy], sentinel lymph node scintigraphy, lung perfusion scintigraphy, and renal function scintigraphy) and 18F-fluorodeoxyglucose positron emission tomography. Nineteen board-certified nuclear medicine technologists evaluated the accuracy and validity of the responses using a 5-point scale. ChatGPT- 4 demonstrated significantly higher accuracy and validity than ChatGPT- 3.5, with 77.9% of responses rated as above average or excellent for accuracy, in comparison to 36.3% for ChatGPT- 3.5. For validity, 73.1% of ChatGPT- 4's responses were rated as above average or excellent, in comparison to 19.6% for ChatGPT- 3.5. ChatGPT- 4 outperformed ChatGPT- 3.5 in all examinations, with notable improvements in bone scintigraphy, lung perfusion scintigraphy, and DAT scintigraphy. These findings suggest that ChatGPT- 4 can be a valuable tool for providing patient explanations of nuclear medicine examinations. However, its application still requires expert supervision, and further research is needed to address potential risks and security concerns.

The REVOLUTION project: planning and performing surgical revascularization based solely on coronary computed tomography angiography.

Coronary computed tomography angiography (CCTA) is a non-invasive diagnostic tool that is increasingly being used as an alternative to invasive coronary angiography (ICA) in patients with suspected coronary artery disease (CAD), providing important information on the extent and severity of CAD. Furthermore, stress CT myocardial perfusion imaging (CT-MPI) and fractional flow reserve derived from CCTA (CT-FFR) have been recently introduced in clinical practice as new tools for evaluating the functional relevance of coronary stenoses. ICA has been the preferred diagnostic method to guide the decision-making process between coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI). Recently, two studies have investigated the feasibility of using CCTA rather than ICA to plan CABG. In patients with three-vessel disease and/or left main CAD, the SYNTAX III REVOLUTION trial concluded that clinical decision-making between CABG and PCI using CCTA had a high level of agreement with treatment decisions based on ICA. In the FASTTRACK study, CABG procedures were planned based on CCTA without knowledge of ICA. CABG guided by CCTA showed to be feasible with an acceptable safety profile in a selected population of complex CAD. These intriguing findings should be confirmed in a large randomized trial on the revascularization outcome by comparing patients who underwent a novel non-invasive vs. a traditional invasive roadmap.

Rubidium ions as a novel therapeutic approach for glioblastoma

Glioblastoma (GBM) is a highly aggressive brain tumor with limited treatment options, mainly due to challenges such as incomplete resection and blood–brain barrier limitations. Rubidium, a naturally occurring alkali metal with favorable biocompatibility, widely used in myocardial and tumor perfusion imaging as a blood flow tracer, is repurposed in this study to investigate its potential therapeutic effects and mechanisms against GBM. The impacts of rubidium ions (Rb⁺) on GBM cells were assessed through functional assays evaluating proliferation, migration, invasion, and apoptosis. RNA sequencing and Western blot analyses were employed to investigate molecular mechanisms, while in vivo models were used to evaluate therapeutic efficacy and safety. Rb⁺ treatment significantly suppressed GBM cell proliferation, migration, and invasion, while inducing apoptosis and cell cycle arrest at the G2/M phase. Mechanistic studies revealed that Rb⁺ downregulated the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, contributing to the induction of apoptosis in tumor cells. In vivo, Rb⁺ exhibited potent anti-tumor activity with no detectable adverse effects on major organs, physiological functions, or behavior in mice. Our findings highlight Rb⁺ as a promising and innovative candidate for GBM therapy, leveraging the PI3K/AKT/mTOR pathway to inhibit tumor growth and promote apoptosis. This study underscores the potential of Rb⁺ in addressing the urgent need for novel GBM treatments, warranting further preclinical and clinical investigations.

Assessment of myocardial dysfunction of patients with systemic lupus erythematosus based on myocardial perfusion imaging and analysis of potential influencing factors.

The incidence and prevalence of systemic lupus erythematosus (SLE) have increased annually over the past decade. The involvement of myocardium is one of the main reasons for the poor prognosis of patients with SLE. Identifying myocardial involvement in patients with autoimmune diseases and providing early targeted treatment can improve patient outcomes. The aim of this study is to evaluate myocardial dysfunction in patients with SLE using 99mTc-MIBI rest gated myocardial perfusion imaging (rGMPI) and to investigate factors associated with myocardial dysfunction. 76 patients with SLE were prospectively enrolled in the study and 46 patients without autoimmune diseases or other inflammatory diseases who had undergone 99mTc-MIBI rGMPI were selected as a control group. Results of relevant blood test indicators, echocardiography and rGMPI were recorded, and comparison was made between the two groups. Meanwhile, based on diagnostic results of rGMPI, SLE patients were divided into myocardial dysfunction group and normal myocardial function group and to analyze the influencing factors of myocardial dysfunction in SLE patients. The incidence of myocardial dysfunction was significantly higher in SLE patients than in controls (30.3% vs 0%, 2= 16.131, p < .001). Moderate/severe disease activity, decreased myocardial perfusion and positive anti-SSA/Ro52kDa antibody were associated with impaired myocardial function in SLE patients (OR = 2.753, 5.359, 3.646; p = .049, 0.015, 0.014). Positive anti-SSA/Ro52kDa antibody was is independently correlated with myocardial dysfunction in SLE patients [OR (95% CI) = 3.159 (1.071-9.316), p = .037]. In conclusion, 99mTc-MIBI rGMPI can noninvasively evaluate myocardial dysfunction in patients with SLE and provide evidence for clinical treatment decisions. Positive anti-SSA/Ro52kDa antibody was an independent risk factor for myocardial dysfunction in SLE patients.

First-pass perfusion imaging using cardiovascular magnetic resonance in patients with various cardiac implantable electronic devices.

The number of patients with cardiac implantable electronic devices (CIEDs) is increasing. However, there is limited experience regarding vasodilator-stress cardiovascular magnetic resonance (CMR) and resulting device artifacts on perfusion images. The aim of this study was to determine CMR image quality in patients with different CIED types for CMR-based perfusion stress testing. A total of 156 patients with active CIEDs underwent CMR on a 1.5-Tesla scanner. Both conventional steady-state-free-precession (SSFP) and modified spoiled gradient-echo (sGE) protocols under stress and resting conditions were used to evaluate image artifacts in a 16-segment segment model of the heart. The study group comprised 39% conventional pacemaker (PM), 4% cardiac resynchronization therapy-pacemaker (CRT-P), 38% conventional implantable cardioverter-defibrillator (ICD), 6% cardiac resynchronization therapy-ICD (CRT-D), and 13% subcutaneous ICD (S-ICD) patients. PM-carriers showed only minor image artifacts in both perfusion protocols. Artifacts caused by ICDs were predominantly located in the left-ventricular (LV) inferolateral and anterior segments. S-ICDs showed the highest extent of artifacts with an anterolateral accentuation. The artifact extent was significantly reduced when sGE-based perfusion was used compared to SSFP-based sequences. 69% of the patients received a stress-perfusion protocol, and elective coronary angiography confirmed the presence of coronary stenosis in three cases. No major safety-relevant issues occurred. Myocardial perfusion imaging by CMR is safe and feasible with moderate-to-high image quality in patients with all types of CIEDs, including non-conditional devices, ICDs, and S-ICDs. A sGE-based perfusion protocol should be preferred in patients with left-sided ICDs, CRT-Ds, or S-ICDs.

Myocardial flow reserve and resting contractility modulate the impact of contractile reserve in patients undergoing rubidum-82 positron emission tomography.

Although ejection fraction reserve (EFR) harbors prognostic value in patients undergoing positron emission tomography (PET) myocardial perfusion imaging (MPI), whether resting EF and myocardial flow reserve (MFR) modulate its prognostic value has not been studied. Consecutive patients undergoing stress/rest MPI using Rb-82 PET between 2019 and 2024 were included. The primary outcome was a composite of death and heart failure (HF) hospitalizations. Multivariable Andersen-Gill Cox models were used to assess the association of EFR with the primary outcome across the spectrum of resting EF and MFR. Restricted cubic splines were used to allow non-linearity. The 50th percentile of EFR served as the reference, with the 25th and 75th percentiles representing low and high EFR. The analysis included 7,737 consecutive patients among whom 463 deaths and 821 HF hospitalizations occurred over a median follow-up of 554 days. A low EFR was associated with a 25% greater risk of the primary outcome (HR: 1.25; 95% CI: 1.16 to 1.35). The association was stronger at higher values of resting EF (HR at EFs of 40% and 70%: 0.99 and 1.21 respectively) and MFR (HR at MFRs of 1 and 3: 1.06 and 1.27 respectively). Similarly, a high EFR carried a protective association that was more pronounced at a higher resting EF and MFR. The prognostic implications of contractile reserve, as measured by EFR, are most pronounced in patients with a higher resting EF and MFR.

Diagnostic reference level, achievable dose, and effective dose estimation in adult hybrid SPECT myocardial perfusion imaging in Institut Jantung Negara

This study aims to establish the diagnostic reference level (DRL), achievable dose (AD), and effective dose (ED) estimation for adult hybrid SPECT myocardial perfusion imaging (MPI) procedures at Institut Jantung Negara (IJN). 737 subjects referred for MPI studies from January to June 2024 were included in the analysis. These subjects underwent either a one-day or two-day Tc-99 m tetrofosmin protocol using a cardiac-dedicated single-photon emission computed tomography (SPECT), either GE SPECT Discovery NM530c or GE SPECT Ventri. All subjects also underwent a cardiac CT scan via an external positron emission tomography/computed tomography (PET/CT) system, GE Discovery MI Digital Ready for either CT attenuation correction (CTAC) or CT coronary artery calcium score (CAC) protocol, depending on their clinical condition. The one-day protocol showed AD of 240.50 MBq and 691.90 MBq for the first and second injections, respectively, with corresponding DRL of 263.63 MBq and 777.93 MBq. The two-day protocol involved higher ADs of 1106.30 MBq and 1073.00 MBq for the first and second injections, with DRL of 1239.50 MBq and 1221.00 MBq, respectively. In the CTAC protocol, the AD for CT dose index volume (CTDIvol) was 2.8 mGy, with a DRL of 4.3 mGy. The dose length product (DLP) had an AD of 53.1 mGy.cm, compared to a DRL of 78.6 mGy.cm. For the CAC protocol, the CTDIvol had an AD of 4.8 mGy, matching the DRL of 4.8 mGy. The DLP showed an AD of 67.8 mGy.cm, with a DRL of 77.5 mGy.cm. The mean cumulated effective dose (EDCUMULATED) for one-day/CTAC, one-day/CAC, two-day/CTAC, and two-day/CAC was 6.69 ± 1.76 mSv, 7.32 ± 1.37 mSv, 10.13 ± 5.31 mSv, and 13.99 ± 3.24 mSv respectively. The average ED relative contribution by SPECT and CT were found to be 78.3% and 21.7% respectively. The DRL, AD, and ED data were successfully established for local MPI practice, contributing to global efforts to harmonize and enhance radiation safety in MPI practices.

Cross-institutional validation of a polar map-free 3D deep learning model for obstructive coronary artery disease prediction using myocardial perfusion imaging: insights into generalizability and bias.

Deep learning (DL) models for predicting obstructive coronary artery disease (CAD) using myocardial perfusion imaging (MPI) have shown potential for enhancing diagnostic accuracy. However, their ability to maintain consistent performance across institutions and demographics remains uncertain. This study aimed to investigate the generalizability and potential biases of an in-house MPI DL model between two hospital-based cohorts. We retrospectively included patients from two medical centers in Taiwan who underwent stress/redistribution thallium-201 MPI followed by invasive coronary angiography within 90 days as the reference standard. A polar map-free 3D DL model trained on 928 MPI images from one center to predict obstructive CAD was tested on internal (933 images) and external (3234 images from the other center) validation sets. Diagnostic performance, assessed using area under receiver operating characteristic curves (AUCs), was compared between the internal and external cohorts, demographic groups, and with the performance of stress total perfusion deficit (TPD). The model showed significantly lower performance in the external cohort compared to the internal cohort in both patient-based (AUC: 0.713 vs. 0.813) and vessel-based (AUC: 0.733 vs. 0.782) analyses, but still outperformed stress TPD (all p < 0.001). The performance was lower in patients who underwent treadmill stress MPI in the internal cohort and in patients over 70 years old in the external cohort. This study demonstrated adequate performance but also limitations in the generalizability of the DL-based MPI model, along with biases related to stress type and patient age. Thorough validation is essential before the clinical implementation of DL MPI models.

Comparative Analysis of Cardiac SPECT Myocardial Perfusion Imaging: Full-Ring Solid-State Detectors Versus Dedicated Cardiac Fixed-Angle Gamma Camera.

Background and Objectives: Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established technique for evaluating myocardial perfusion and function in patients with suspected or known coronary artery disease. While conventional dual-detector SPECT scanners have limitations in spatial resolution and photon detection sensitivity, recent advancements, including full-ring solid-state cadmium zinc telluride (CZT) detectors, offer enhanced image quality and improved diagnostic accuracy. This study aimed to compare the performance of Veriton-CT, a full-ring CZT SPECT system, with GE Discovery 530c, a dedicated cardiac fixed-angle gamma camera, in myocardial perfusion imaging and their correlation with coronary angiography findings. Materials and Methods: This was a prospective study that analyzed 21 patients who underwent MPI at the Department of Nuclear Medicine, Lithuanian University of Health Sciences, Kauno Klinikos. A one-day stress-rest protocol using 99mTc-Sestamibi was employed, with stress testing performed via bicycle ergometry or pharmacological induction. MPI was first conducted using GE Discovery 530c (GE Health Care, Boston, MA, USA), followed by imaging on Veriton-CT, which included low-dose CT for attenuation correction. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were analyzed and compared between both imaging modalities. Coronary angiography results were retrospectively collected, and lesion-based analysis was performed to assess the correlation between imaging results and the presence of significant coronary artery stenosis (≥35% and ≥70% narrowing). Image quality and the certainty of distinguishing the inferior myocardial wall from extracardiac structures were also evaluated by two independent researchers with differing levels of experience. Results: Among the 14 patients included in the final analysis, Veriton-CT was more likely to classify MPI scans as normal (64.3%) compared to GE Discovery 530c (28.6%). Additionally, Veriton-CT provided a better assessment of the right coronary artery (RCA) basin, showing greater agreement with coronary angiography findings than GE Discovery 530c, although the difference was not statistically significant. No significant differences in lesion overlap were observed for the left anterior descending artery (LAD) or left circumflex artery (LCx) basins. Furthermore, the image quality assessment revealed slightly better delineation of extracardiac structures using Veriton-CT (Spectrum Dynamics Medical, Caesarea, Israel), particularly when evaluated by an experienced researcher. However, no significant difference was observed when assessed by a less experienced observer. Conclusions: Our findings suggest that Veriton-CT, with its full-ring CZT detector system, may offer advantages over fixed-angle gamma cameras in improving image quality and reducing attenuation artifacts in MPI. Although the difference in correlations with coronary angiography findings was not statistically significant, Veriton-CT showed a trend toward better agreement, particularly in the RCA basin. These results indicate that full-ring SPECT imaging could improve the diagnostic accuracy of non-invasive MPI, potentially reducing the need for unnecessary invasive angiography. Further studies with larger patient cohorts are required to confirm these findings and evaluate the clinical impact of full-ring SPECT technology in myocardial perfusion imaging.

Myocardial Perfusion Imaging With PET; A Head-to-Head Comparison of 82Rubidium Versus 15O-water Tracers Using Invasive Coronary Measurements as Reference.

Myocardial perfusion imaging by positron emission tomography (PET) is recommended as a first-line test in stable patients with chest pain symptoms and as a selective second-line test after an abnormal coronary computed tomography angiography (CTA). It is, however, unknown whether the use of Rubidium-82 (82Rb) versus [15O]H2O (15O-water) affects the diagnostic performance in coronary artery disease (CAD). The aim of this study was to compare 82Rb-PET versus 15O-water-PET head-to-head for diagnosing obstructive CAD. The study included consecutive patients (n=1000) referred for CTA with symptoms suggestive of obstructive CAD. Patients with suspected stenosis based on CTA were referred for both 82Rb-PET, 15O-water-PET, and subsequently invasive coronary angiography (ICA), including 3-vessel fractional flow reserve and coronary flow reserve measurements. In total, 196/270 (73%) patients with suspected stenosis on CTA completed 82Rb-PET, 15O-water-PET, and ICA. Myocardial blood flow measurements from 82Rb-PET and 15O-water-PET correlated strongly at rest (ρ, 0.62-0.69) but only moderately during hyperemia (ρ, 0.41-0.59). Only weak correlations were demonstrated between myocardial blood flow reserve by both PET tracers compared with ICA coronary flow reserve (ρ, 0.11-0.38). Hemodynamically obstructive CAD defined as ICA fractional flow reserve ≤0.80, was identified in 86/196 (44%) patients. Using predefined cutoffs, the diagnostic accuracies of 82Rb-PET versus 15O-water-PET were similar (sensitivity 69% [58-78%] versus 71% [60-80%], P=0.59; specificity 85% [76-91%] versus 77% [68-85%], P=0.12). Using ICA diameter stenoses >70% as a reference, only 48/196 (24%) patients had anatomically severe CAD, and 82Rb-PET and 15O-water-PET sensitivities increased to >85%. For detection of obstructive CAD by PET myocardial perfusion imaging, 82Rb versus 15O-water have similar diagnostic performance. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04707859.