Biodistribution and dosimetry of Zirconium-labeled microbiota transplants in the pig gut.

Background: The gastrointestinal (GI) microbiota, composed of diverse microbial communities, is essential for physiological processes, including immune modulation. Strains such as Escherichia coli Nissle 1917 support gut health by reducing inflammation and resisting pathogens. Microbial therapies using such strains may restore GI balance and offer alternatives to antibiotics, whose overuse contributes to antibiotic resistance.

Association of white matter injury and neuroinflammation in the post-acute phase after ischemic stroke using [F]FEPPA-PET/MRI.

Background: Cerebral white matter (WM) injury after ischemic stroke is associated with post-stroke cognitive impairment (PSCI), however, the interaction between sustained neuroinflammation and post-stroke WM injury is not well understood. Hybrid PET/MRI can provide insight into pathophysiological mechanisms linking chronic neuroinflammation, ischemic WM injury, and PSCI. Using PET/MRI, this study investigated the relationship between [F]FEPPA standardized uptake value ratio (SUVr) measurements of glial activation and diffusion tensor imaging (DTI) measurements of microstructure integrity in brain WM regions in the chronic phase at 6-months after acute ischemic stroke.

Complexities of Atrial Fibrosis Imaging: Exploring Relationships Between Endocardial Voltage, Extracellular Volume, and Sympathetic Innervation.

Background: Atrial fibrillation is associated with abnormal synchronization of left atrial electrical activity and substantially increased risk of myocardial infarction, stroke and heart failure.

Objectives: This study sought to investigate, in a canine model of atrial fibrosis, the relationship between left atrial sympathetic innervation (by C-hydroxyephedrine positron emission tomography [PET]), extracellular volume (by magnetic resonance imaging [MRI]) and endocardial voltage (by voltage mapping), measured in vivo with the extent of left atrial (LA) tissue fibrosis measured post mortem with histology.

Methods: A total of 9 adult female canines were imaged with hybrid PET/MRI.

Different sodium concentrations of noncancerous and cancerous prostate tissue seen on MRI using an external coil.

Background: Sodium (Na) MRI of prostate cancer (PCa) is a novel but underdocumented technique conventionally acquired using an endorectal coil. These endorectal coils are associated with challenges (e.g.

Quantitative Analysis of Early White Matter Damage in Cuprizone Mouse Model of Demyelination Using 7.0 T MRI Multiparametric Approach.

Magnetic Resonance Imaging (MRI) is commonly used to follow the progression of neurodegenerative conditions, including multiple sclerosis (MS). MRI is limited by a lack of correlation between imaging results and clinical presentations, referred to as the clinico-radiological paradox. Animal models are commonly used to mimic the progression of human neurodegeneration and as a tool to help resolve the paradox.

Design, Synthesis, and Preclinical Evaluation of a High-Affinity F-Labeled Radioligand for Myocardial Growth Hormone Secretagogue Receptor Before and After Myocardial Infarction.

The peptide hormone ghrelin is produced in cardiomyocytes and acts through the myocardial growth hormone secretagogue receptor (GHSR) to promote cardiomyocyte survival. Administration of ghrelin may have therapeutic effects on post-myocardial infarction (MI) outcomes. Therefore, there is a need to develop molecular imaging probes that can track the dynamics of GHSR in health and disease to better predict the effectiveness of ghrelin-based therapeutics.

Characterizing the association between complement-mediated TMA and cognitive dysfunction using MRI and neurocognitive assessment.

Complement-mediated thrombotic microangiopathy (CM-TMA) is a rare, life-threatening thrombotic microangiopathy caused by a defect in the alternative complement pathway. It is associated with renal failure and acute encephalopathy, but long-term neurocognitive effects are uncertain. Using magnetic resonance imaging (MRI) and neurocognitive tests, we can further evaluate the long-term neurocognitive complications in CM-TMA and compare them with controls.

Magnetic resonance metrics for identification of cuprizone-induced demyelination in the mouse model of neurodegeneration: a review.

Neurodegenerative disorders, including Multiple Sclerosis (MS), are heterogenous disorders which affect the myelin sheath of the central nervous system (CNS). Magnetic Resonance Imaging (MRI) provides a non-invasive method for studying, diagnosing, and monitoring disease progression. As an emerging research area, many studies have attempted to connect MR metrics to underlying pathophysiological presentations of heterogenous neurodegeneration.

Myocardial glucose suppression may interfere with the detection of inflammatory cells with FDG-PET as suggested in a canine model of myocardial infarction.

Background: After myocardial infarction, fibrosis and an ongoing dysregulated inflammatory response have been shown to lead to adverse cardiac remodeling. FDG PET is an imaging modality sensitive to inflammation as long as suppression protocols are observed while gadolinium enhanced MRI can be used to determine extracellular volume (ECV), a measure of fibrosis. In patients, glucose suppression is achieved variously through a high fat diet, fasting and injection of heparin.

Probing Evidence of Cerebral White Matter Microstructural Disruptions in Ischemic Heart Disease Before and Following Cardiac Rehabilitation: A Diffusion Tensor MR Imaging Study.

Background: Ischemic heart disease (IHD) is linked to brain white matter (WM) breakdown but how age or disease effects WM integrity, and whether it is reversible using cardiac rehabilitation (CR), remains unclear.

Purpose: To assess the effects of brain aging, cardiovascular disease, and CR on WM microstructure in brains of IHD patients following a cardiac event.

Study Type: Retrospective.

The use of Lutetium-177 PSMA radioligand therapy with high dose rate brachytherapy for locally recurrent prostate cancer after previous definitive radiation therapy: a randomized, single-institution, phase I/II study (ROADSTER).

Background: Isolated local failure (ILF) can occur in patients who initially receive definitive radiation therapy for prostate cancer. Salvage therapy for ILF includes high dose rate (HDR) brachytherapy. Prostate Specific Membrane Antigen (PSMA) Positron Emission Tomography (PET) can accurately detect ILF and can exclude extraprostatic disease.

Glucose Infusion Induced Change in Intracellular pH and Its Relationship with Tumor Glycolysis in a C6 Rat Model of Glioblastoma.

Introduction: The reliance on glycolytic metabolism is a hallmark of tumor metabolism. Excess acid and protons are produced, leading to an acidic tumor environment. Therefore, we explored the relationship between the tumor glycolytic metabolism and tissue pH by comparing F-fluorodeoxyglucose positron emission tomography (FDG-PET) and hyperpolarized [1-C]pyruvate MR spectroscopy imaging (MRSI) to chemical exchange saturation transfer (CEST) MRI measurements of tumor pH.

Attenuation correction for PET/MRI to measure tracer activity surrounding total knee arthroplasty.

Background: Positron emission tomography (PET) in combination with magnetic resonance imaging (MRI) could allow inflammatory complications near total knee arthroplasty (TKA) to be studied early in their development. However, attenuation of the PET signal by the metal TKA implants imparts substantial error into measurements of tracer activity, and conventional MR-based attenuation correction (AC) methods have large signal voids in the vicinity of metal implants.

Purpose: To evaluate a segmentation-based AC approach to measure tracer uptake from PET/MRI scans near TKA implants.

Glial activation positron emission tomography imaging in radiation treatment of breast cancer brain metastases.

Brain metastases affect more breast cancer patients than ever before due to increased overall patient survival with improved molecularly targeted treatments. Approximately 25-34% of breast cancer patients develop brain metastases in their lifetime. Due to the blood-brain barrier (BBB), the standard treatment for breast cancer brain metastases (BCBM) is surgery, stereotactic radiosurgery (SRS) and/or whole brain radiation therapy (WBRT).

Short-duration dynamic [F]DCFPyL PET and CT perfusion imaging to localize dominant intraprostatic lesions in prostate cancer: validation against digital histopathology and comparison to [F]DCFPyL PET/MR at 120 minutes.

Purpose: Localized prostate cancer (PCa) in patients is characterized by a dominant focus in the gland (dominant intraprostatic lesion, DIL). Accurate DIL identification may enable more accurate diagnosis and therapy through more precise targeting of biopsy, radiotherapy and focal ablative therapies. The goal of this study is to validate the performance of [F]DCFPyL PET and CT perfusion (CTP) for detecting and localizing DIL against digital histopathological images.

Blood-brain barrier permeability in survivors of immune-mediated thrombotic thrombocytopenic purpura: a pilot study.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening disorder of systemic microthrombosis and organ ischemia. The etiology of chronic cerebrovascular outcomes in iTTP survivors is largely unknown. In this pilot study, we measured blood-brain barrier (BBB) permeability in patients with iTTP at the start of remission and 6 months later.

F-FDG PET-guided diffusion tractography reveals white matter abnormalities around the epileptic focus in medically refractory epilepsy: implications for epilepsy surgical evaluation.

Background: Hybrid PET/MRI can non-invasively improve localization and delineation of the epileptic focus (EF) prior to surgical resection in medically refractory epilepsy (MRE), especially when MRI is negative or equivocal. In this study, we developed a PET-guided diffusion tractography (PET/DTI) approach combining F-fluorodeoxyglucose PET (FDG-PET) and diffusion MRI to investigate white matter (WM) integrity in MRI-negative MRE patients and its potential impact on epilepsy surgical planning.

Methods: FDG-PET and diffusion MRI of 14 MRI-negative or equivocal MRE patients were used to retrospectively pilot the PET/DTI approach.

Improved PET/MRI accuracy by use of static transmission source in empirically derived hardware attenuation correction.

Background: Accurate quantification of radioactivity, measured by an integrated positron emission tomography (PET) and magnetic resonance imaging (MRI) system, is still a challenge. One aspect of such a challenge is to correct for the hardware attenuation, such as the patient table and radio frequency (RF) resonators. For PET/MRI systems, computed tomography (CT) is commonly used to produce hardware attenuation correction (AC) maps, by converting Hounsfield units (HU) to a linear attenuation coefficients (LAC) map at the PET energy level 511 keV, using a bilinear model.

An evaluation of the diagnostic equivalence of F-FDG-PET between hybrid PET/MRI and PET/CT in drug-resistant epilepsy: A pilot study.

Objective: Hybrid PET/MRI may improve detection of seizure-onset zone (SOZ) in drug-resistant epilepsy (DRE), however, concerns over PET bias from MRI-based attenuation correction (MRAC) have limited clinical adoption of PET/MRI. This study evaluated the diagnostic equivalency and potential clinical value of PET/MRI against PET/CT in DRE.

Materials And Methods: MRI, FDG-PET and CT images (n = 18) were acquired using a hybrid PET/MRI and a CT scanner.

Multimodality In Vivo Imaging of Perfusion and Glycolysis in a Rat Model of C6 Glioma.

Purpose: Chemical exchange saturation transfer MRI using an infusion of glucose (glucoCEST) is sensitive to the distribution of glucose in vivo; however, whether glucoCEST is more related to perfusion or glycolysis is still debatable. We compared glucoCEST to computed tomography perfusion (CTP), [F] fluorodeoxyglucose positron emission tomography (FDG-PET), and hyperpolarized [1-C] pyruvate magnetic resonance spectroscopy imaging (MRSI) in a C6 rat model of glioma to determine if glucoCEST is more strongly correlated with measurements of perfusion or glycolysis.

Methods: 10 C6 glioma cells were implanted in Wistar rat brains (n = 11).

TSPO PET detects acute neuroinflammation but not diffuse chronically activated MHCII microglia in the rat.

Background: Accurate and sensitive imaging biomarkers are required to study the progression of white matter (WM) inflammation in neurodegenerative diseases. Radioligands targeting the translocator protein (TSPO) are considered sensitive indicators of neuroinflammation, but it is not clear how well the expression of TSPO coincides with major histocompatibility complex class II (MHCII) molecules in WM. This study aimed to test the ability of TSPO to detect activated WM microglia that are immunohistochemically positive for MHCII in rat models of prodromal Alzheimer's disease and acute subcortical stroke.