Cardiovascular PET imaging of fibroblast activation A review of the current literature.

Fibrosis is one of the key healing responses to injury, especially within the heart where it helps to maintain structural integrity following acute insults such as myocardial infarction. However, if it becomes dysregulated then fibrosis can become maladaptive leading to adverse remodelling, impaired cardiac function and heart failure. Fibroblast activation protein is exclusively expressed by activated fibroblasts, the key effector cells of fibrogenesis, and has a unique extracellular domain that is an ideal ligand for novel molecular imaging probes.

Regional brain glucose uptake following gastric bypass surgery during normo- and hypoglycemic clamp: a pilot FDG-PET study.

Purpose: We aimed to characterize the RYGB-induced changes in the dynamics of brain glucose uptake. We addressed heterogeneity between brain regions during experimental normo- and hypoglycemia and explored associations with anthropometric and metabolic outcomes of RYGB.

Methods: Analyses of regional brain glucose uptake were performed on 9 individuals with obesity and no diabetes, investigated with combined brain F-FDG-PET and fMRI during hyperinsulinemic normo- and hypoglycemic clamp, one month before and four months after RYGB.

Quantitation of mitral regurgitation using positron emission tomography.

Background: Cardiac positron emission tomography (PET) offers non-invasive assessment of perfusion and left ventricular (LV) function from a single dynamic scan. However, no prior assessment of mitral regurgitation severity by PET has been presented. Application of indicator dilution techniques and gated image analyses to PET data enables calculation of forward stroke volume and total LV stroke volume.

Evaluation of [C]UCB-A positron emission tomography in human brains.

Background: In preclinical studies, the positron emission tomography (PET) imaging with [C]UCB-A provided promising results for imaging synaptic vesicle protein 2A (SV2A) as a proxy for synaptic density. This paper reports the first-in-human [C]UCB-A PET study to characterise its kinetics in healthy subjects and further evaluate SV2A-specific binding.

Results: Twelve healthy subjects underwent 90-min baseline [C]UCB-A scans with PET/MRI, with two subjects participating in an additional blocking scan with the same scanning procedure after a single dose of levetiracetam (1500 mg).

Radiation dosimetry of para-chloro-2-[F]fluoroethyl-etomidate: a PET tracer for adrenocortical imaging.

Background: [C]metomidate, a methyl ester analogue of etomidate, is used for positron emission tomography of adrenocortical cancer, and has been tested in recent clinical trials for lateralization in primary aldosteronism (PA). However, in PA, visualization as well as uptake quantification are hampered by the tracer's rather high non-specific liver uptake, and its overall clinical usefulness is also limited by the short 20-minute half-life of carbon-11. Therefore, we evaluated para-chloro-2-[F]fluoroethyl-etomidate, [F]CETO, a fluorine-18 (T=109.

Short-term effects of obesity surgery versus low-energy diet on body composition and tissue-specific glucose uptake: a randomised clinical study using whole-body integrated F-FDG-PET/MRI.

Aims/hypothesis: Obesity surgery (OS) and diet-induced weight loss rapidly improve insulin resistance. We aim to investigate the impact of either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery compared with a diet low in energy (low-calorie diet; LCD) on body composition, glucose control and insulin sensitivity, assessed both at the global and tissue-specific level in individuals with obesity but not diabetes.

Methods: In this parallel group randomised controlled trial, patients on a waiting list for OS were randomised (no blinding, sealed envelopes) to either undergo surgery directly or undergo an LCD before surgery.

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.

GABAA Receptor Availability in Relation to Cortical Excitability in Depressed and Healthy: A Positron Emission Tomography and Transcranial Magnetic Stimulation Study.

Introduction: Gamma-aminobutyric acid (GABA) deficiency is suggested in depressive disorders, along with alterations in cortical excitability. However, whether these excitability changes are related to GABAA receptor availability is largely unknown. Our aim was to assess the correlation between these measures in depressed patients and healthy controls.

Comparison of quantitative [C]PE2I brain PET studies between an integrated PET/MR and a stand-alone PET system.

PET/MR systems demanded great efforts for accurate attenuation correction (AC) but differences in technology, geometry and hardware attenuation may also affect quantitative results. Dedicated PET systems using transmission-based AC are regarded as the gold standard for quantitative brain PET. The study aim was to investigate the agreement between quantitative PET outcomes from a PET/MR scanner against a stand-alone PET system.

Impact of simulated reduced injected dose on the assessment of amyloid PET scans.

Purpose: To investigate the impact of reduced injected doses on the quantitative and qualitative assessment of the amyloid PET tracers [F]flutemetamol and [F]florbetaben.

Methods: Cognitively impaired and unimpaired individuals (N = 250, 36% Aβ-positive) were included and injected with [F]flutemetamol (N = 175) or [F]florbetaben (N = 75). PET scans were acquired in list-mode (90-110 min post-injection) and reduced-dose images were simulated to generate images of 75, 50, 25, 12.

RetroBioCat Database: A Platform for Collaborative Curation and Automated Meta-Analysis of Biocatalysis Data.

Despite the increasing use of biocatalysis for organic synthesis, there are currently no databases that adequately capture synthetic biotransformations. The lack of a biocatalysis database prevents accelerating biocatalyst characterization efforts from being leveraged to quickly identify candidate enzymes for reactions or cascades, slowing their development. The RetroBioCat Database (available at retrobiocat.

Detection and correction of patient motion in dynamic O-water PET MPI.

Background: Patient motion constitutes a limitation to O-water cardiac PET imaging. We examined the ability of image readers to detect and correct patient motion using simulated motion data and clinical patient scans.

Methods: Simulated data consisting of 16 motions applied to 10 motion-free scans were motion corrected using two approaches, pre-analysis and post-analysis for motion identification.

Human Epidermal Growth Factor Receptor 2-Targeting [Ga]Ga-ABY-025 PET/CT Predicts Early Metabolic Response in Metastatic Breast Cancer.

Imaging using the human epidermal growth factor receptor 2 (HER2)-binding tracer Ga-labeled Z-Cys-MMA-DOTA ([Ga]Ga-ABY-025) was shown to reflect HER2 status determined by immunohistochemistry and in situ hybridization in metastatic breast cancer (MBC). This single-center open-label phase II study investigated how [Ga]Ga-ABY-025 uptake corresponds to biopsy results and early treatment response in both primary breast cancer (PBC) planned for neoadjuvant chemotherapy and MBC. Forty patients with known positive HER2 status were included: 19 with PBC and 21 with MBC (median, 3 previous treatments).

Impact of administered amount of peptide on tumor dosimetry at the first cycle of peptide receptor radionuclide therapy (PRRT) in relation to total tumor somatostatin receptor expression.

Background: The accumulation of Lu-DOTATATE might be influenced by the amount of administered peptide in relation to the tumor somatostatin receptor expression. The effect of the administered peptide mass on the resulting absorbed dose in tumors and normal organs has not previously been assessed in relation to the patients' tumor load.

Method: Patients with small intestinal (n = 141) and pancreatic (n = 62) neuroendocrine tumors (NETs) who underwent PRRT were selected for retrospective evaluation.

Striatal dopamine transporter and receptor availability correlate with relative cerebral blood flow measured with [C]PE2I, [F]FE-PE2I and [C]raclopride PET in healthy individuals.

The aim of this retrospective study was to investigate relationships between relative cerebral blood flow and striatal dopamine transporter and dopamine D2/3 availability in healthy subjects. The data comprised dynamic PET scans with two dopamine transporter tracers [C]PE2I (n = 20) and [F]FE-PE2I (n = 20) and the D2/3 tracer [C]raclopride (n = 18). Subjects with a [C]PE2I scan also underwent a dynamic scan with the serotonin transporter tracer [C]DASB.

Image-derived input functions from dynamic O-water PET scans using penalised reconstruction.

Background: Quantitative positron emission tomography (PET) scans of the brain typically require arterial blood sampling but this is complicated and logistically challenging. One solution to remove the need for arterial blood sampling is the use of image-derived input functions (IDIFs). Obtaining accurate IDIFs, however, has proved to be challenging, mainly due to the limited resolution of PET.

Left-ventricular volumes and ejection fraction from cardiac ECG-gated O-water positron emission tomography compared to cardiac magnetic resonance imaging using simultaneous hybrid PET/MR.

Background: O-water PET is the gold standard for noninvasive quantification of myocardial blood flow. In addition to evaluation of ischemia, the assessment of cardiac function and remodeling is important in all cardiac diseases. However, since O-water is freely diffusible and standard uptake images show little contrast between the myocardium and blood pool, the assessment of left-ventricular (LV) volumes and ejection fraction (EF) is challenging.

Nuclear medicine in the assessment and prevention of cancer therapy-related cardiotoxicity: prospects and proposal of use by the European Association of Nuclear Medicine (EANM).

Cardiotoxicity may present as (pulmonary) hypertension, acute and chronic coronary syndromes, venous thromboembolism, cardiomyopathies/heart failure, arrhythmia, valvular heart disease, peripheral arterial disease, and myocarditis. Many of these disease entities can be diagnosed by established cardiovascular diagnostic pathways. Nuclear medicine, however, has proven promising in the diagnosis of cardiomyopathies/heart failure, and peri- and myocarditis as well as arterial inflammation.

Serotonin and dopamine transporter availability in social anxiety disorder after combined treatment with escitalopram and cognitive-behavioral therapy.

Selective serotonin reuptake inhibitors (SSRIs) and internet-based cognitive behavioral therapy (ICBT) are recommended treatments of social anxiety disorder (SAD), and often combined, but their effects on monoaminergic signaling are not well understood. In this multi-tracer positron emission tomography (PET) study, 24 patients with SAD were randomized to treatment with escitalopram+ICBT or placebo+ICBT under double-blind conditions. Before and after 9 weeks of treatment, patients were examined with positron emission tomography and the radioligands [C]DASB and [C]PE2I, probing the serotonin (SERT) and dopamine (DAT) transporter proteins respectively.