The Western Denmark Myocardial Perfusion Imaging Registry: A Review and Validation Study.

Purpose: Myocardial perfusion imaging (MPI) procedures from single photon emission computed tomography and positron emission tomography imaging have been registered in the Western Denmark Heart Registry (WDHR) since 2017 as a sub-registry (WDHR-MPI). The aim was to review the content, quality, and research potential of the WDHR-MPI and assess the completeness and validity of its key variables.

Patients And Methods: Using the Danish National Patient Registry (DNPR) as a reference, we calculated the completeness of procedure registration as the proportion of procedures registered in the WDHR-MPI from 2017 to 2021.

Long Axial Field-of-View PET/CT: New Opportunities for Pediatric Imaging.

The combined use of Positron Emission Tomography (PET) and Computed Tomography (CT) has become increasingly vital for diagnosing and managing oncological and infectious diseases in pediatric patients. The introduction of long axial field-of-view (LAFOV) PET/CT scanners, also known as "Total Body PET/CT," marks a significant advancement in nuclear medicine. This new technology enables faster pediatric imaging with substantially reduced radiation exposure and essentially eliminates the need for sedation, addressing previous critical concerns in pediatric imaging.

Cerebral and myocardial kinetics of [C]acetoacetate and [C]β-hydroxybutyrate: A comparative crossover study in healthy rats.

Background: Ketone metabolism has been studied using positron emission tomography (PET) with the radiotracers [C]acetoacetate and [C]β-hydroxybutyrate. However, whether these two radiotracers actually yield equivalent estimates of cerebral and myocardial ketone metabolism has not yet been investigated. This study aimed to investigate and compare the kinetics of both tracers in the brain and heart of healthy rats under varying levels of circulating ketones at baseline and after a single-dose exogenous ketone ester (KE) supplement.

Proteomic Profiling of Lymph Nodes Differentiates Classic Hodgkin Lymphoma With and Without Skeletal Involvement.

Classic Hodgkin lymphoma (CHL) is a highly curable disease, even in advanced stages. Controversy remains over whether bone involvement negatively affects overall and progression-free survival in patients treated with intensive chemotherapy regimens. Whether cases that present with bone lesions harbor specific tumor microenvironmental features is unknown.

Microvascular resistance reserve: impact on health status and myocardial perfusion after revascularization in chronic coronary syndrome.

Background And Aims: The microvascular resistance reserve (MRR) is a novel invasive index of the microcirculation, which is independent of epicardial stenoses, and MRR has both diagnostic and prognostic implications. This study investigates whether MRR is associated with health status outcomes by revascularization in patients with moderate coronary stenoses.

Methods: Consecutive patients with stable chest pain and moderate (30-90% diameter) stenoses on invasive coronary angiography (n=222) underwent invasive physiology assessment.

Three Weeks on a Ketogenic Diet Reduces Free Testosterone and Free Estradiol in Middle-Aged Obese Men and Women.

Background: Beta-hydroxybuturate (-OHB) supplements are commonly utilized in sports by both recreational and professional athletes. In a recent study, we observed a drop in testosterone levels following the oral ingestion of racemic sodium--OHB. In this investigation, we aim to determine whether a single oral dose of ketone ester (study I) and prolonged endogenous ketosis (study II) also reduces testosterone levels.

Pulmonary vascular adaptations to hypoxia in elite breath-hold divers.

Introduction: Elite breath-hold divers (BHD) possess several oxygen conserving adaptations to endure long dives similar to diving mammals. During dives, Bottlenose Dolphins may increase the alveolar ventilation (V) to perfusion (Q) ratio to increase alveolar oxygen delivery. We hypothesized that BHD possess similar adaptive mechanisms during apnea.

Improved Diagnostic Accuracy for Polymyalgia Rheumatica using FDG-PET/CT with Clinical Diagnosis or 2012 ACR/EULAR Classification Criteria.

Purpose: In routine care, clinicians may employ 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) computed tomography (CT) to validate their initial clinical diagnosis of polymyalgia rheumatica (PMR). Nevertheless, the diagnostic utility of combining FDG-PET/CT findings with clinical presentation has not been explored. Therefore, this study aimed to investigate whether the diagnostic accuracy for PMR could be enhanced by combining FDG-PET/CT findings with the clinical baseline diagnosis or the 2012 ACR/EULAR clinical classification criteria for PMR.

A 3-Week Ketogenic Diet Increases Skeletal Muscle Insulin Sensitivity in Individuals With Obesity: A Randomized Controlled Crossover Trial.

A ketogenic diet (KD) can induce weight loss and improve glycemic regulation, potentially reducing the risk of type 2 diabetes development. To elucidate the underlying mechanisms behind these beneficial effects of a KD, we investigated the impact of a KD on organ-specific insulin sensitivity (IS) in skeletal muscle, liver, and adipose tissue. We hypothesized that a KD would increase IS in skeletal muscle.

Whole-body parametric mapping of tumour perfusion in metastatic prostate cancer using long axial field-of-view [O]HO PET.

Purpose: Tumour perfusion is a nutrient-agnostic biomarker for cancer metabolic rate. Use of tumour perfusion for cancer growth assessment has been limited by complicated image acquisition, image analysis and limited field-of-view scanners. Long axial field-of-view (LAFOV) PET scan using [O]HO, allows quantitative assessment of whole-body tumour perfusion.

Similar insulin regulation of splanchnic FFA and VLDL-TG in men with nonalcoholic hepatic steatosis and steatohepatitis.

This study aimed to determine whether obese men with nonalcoholic fatty liver disease (NAFLD) display differences between those with simple steatosis versus steatohepatitis (NASH) in splanchnic and hepatic FFA and VLDL-triglycerides (VLDL-TG) balances. The study involved 17 obese men with biopsy-proven NAFLD (9 with NASH and 8 with simple steatosis). We used hepatic vein catheterization in combination with [H]palmitate and [C]VLDL-TG tracers to measure splanchnic palmitate and VLDL-TG uptake and release rates during basal and hyperinsulinemic conditions.

Myocardial Blood Flow by Magnetic Resonance in Patients With Suspected Coronary Stenosis: Comparison to PET and Invasive Physiology.

Background: Despite recent guideline recommendations, quantitative perfusion (QP) estimates of myocardial blood flow from cardiac magnetic resonance (CMR) have only been sparsely validated. Furthermore, the additional diagnostic value of utilizing QP in addition to the traditional visual expert interpretation of stress-perfusion CMR remains unknown. The aim was to investigate the correlation between myocardial blood flow measurements estimated by CMR, positron emission tomography, and invasive coronary thermodilution.

Hemoglobin concentration and blood shift during dry static apnea in elite breath hold divers.

Introduction: Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea.

Splenic switch-off in [O]HO-positron emission tomography myocardial perfusion imaging using parametric blood flow images.

Background: Evaluation of sufficient adenosine response constitutes a significant challenge in myocardial perfusion imaging (MPI). Splenic switch-off in MPI studies denotes a visually (qualitatively) reduced splenic radiotracer signal during adenosine stress and is considered indicative of sufficient cardiac vasodilation. In this study, we examined semi-quantitative and quantitative approaches to splenic switch-off assessment using [O]HO-PET with either summed activity images or calculated parametric splenic blood flow images.

The effect of prednisolone and a short-term prednisolone discontinuation for the diagnostic accuracy of FDG-PET/CT in polymyalgia rheumatica-a prospective study of 101 patients.

Purpose: 2-[18F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has been suggested as an imaging modality to diagnose polymyalgia rheumatica (PMR). However, the applicability of FDG-PET/CT remains unclear, especially following glucocorticoid administration. This study aimed to investigate the diagnostic accuracy of FDG-PET/CT before and during prednisolone treatment, as well as following short-term prednisolone discontinuation.

Enantiomer-Specific Cardiovascular Effects of the Ketone Body 3-Hydroxybutyrate.

Background: The ketone body 3-hydroxybutyrate (3-OHB) increases cardiac output (CO) by 35% to 40% in healthy people and people with heart failure. The mechanisms underlying the effects of 3-OHB on myocardial contractility and loading conditions as well as the cardiovascular effects of its enantiomeric forms, D-3-OHB and L-3-OHB, remain undetermined.

Methods And Results: Three groups of 8 pigs each underwent a randomized, crossover study.

Advances in PET Imaging of Large Vessel Vasculitis: An Update and Future Trends.

Systemic vasculitides are autoimmune diseases characterized by inflammation of blood vessels. They are categorized based on the size of the preferentially affected blood vessels: large-, medium-, and small-vessel vasculitides. The main forms of large-vessel vasculitis include giant cell arteritis (GCA) and Takayasu arteritis (TAK).

Incidental [18F]FDG-avid focuses in parotid glands on PET/CT.

Background: The number of unexpected focal [18F]FDG-avid findings (incidentalomas) within the parotid gland (PGI) continues to increase with the expanding use of PET/CT scanning. The prevalence of malignancy in PGIs is uncertain and appropriate management is unsettled.

Aims: We aimed to explore the underlying pathologies associated with PGI.

Increased lesion detectability in patients with locally advanced breast cancer-A pilot study using dynamic whole-body [F]FDG PET/CT.

Background: Accurate diagnosis of axillary lymph node (ALN) metastases is essential for prognosis and treatment planning in breast cancer. Evaluation of ALN is done by ultrasound, which is limited by inter-operator variability, and by sentinel lymph node biopsy and/or ALN dissection, none of which are without risks and/or long-term complications. It is known that conventional 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) positron emission tomography/computed tomography (PET/CT) has limited sensitivity for ALN metastases.