BACKGROUND:Deep brain stimulation (DBS) is an evolving technique for the treatment of various psychiatric disorders refractory to conventional pharmacotherapy. Neuroimaging with positron emission tomography (PET) has an important role in the planning, delivery, and post-surgical monitoring of DBS. This study aims to determine the clinical relevance of PET as a biomarker of disease status and response to DBS for patients with psychiatric disorders. METHODS:We performed a systematic review of the PubMed, Web of Science, and Scopus databases to identify original research studies that applied PET to study the effects of DBS for patients with psychiatric conditions (major depressive disorder, obsessive-compulsive disorder (OCD), substance use disorder, anorexia nervosa, and schizophrenia). Information on study design, PET findings, clinical measures, and outcomes were recorded. RESULTS:From an initial search of 149 articles, we identified 27 studies on depression (n = 11), OCD (n = 8), substance use disorder (n = 3), anorexia nervosa (n = 3), and schizophrenia (n = 1) that met selection criteria for our qualitative analysis. PET imaging with various radiotracers (18F-fluorodeoxyglucose (FDG) for glucose metabolism, 15O-water for cerebral blood flow, 11C-raclopride for dopamine transmission) revealed distinct molecular alterations in patients before and after DBS. Changes in PET signal generally correlated with clinical improvements in psychiatric symptom scores. Comparisons of studies that targeted different brain structures for DBS demonstrated unique activation patterns on PET, though the clinical significance of these changes remains unclear. CONCLUSIONS:PET provides insight into the effects of DBS on the molecular activity of the brain, which may improve patient selection for surgery, prognostication, and long-term monitoring.

A growing number of advanced neuroimaging studies have been used to evaluate the nature of consciousness. Such studies have focused on various states of consciousness as well as ways of inducing altered states of consciousness. Various states of consciousness include the normal waking state, sleep states, the brain under anesthesia, and the impact of disorders such as seizures or schizophrenia. The induction of altered states of consciousness includes practices such as meditation or the use of psychoactive substances leading to psychedelic effects. This paper reviews some of the relevant research and then considers some of limitations and challenges for studying consciousness with neuroimaging, particularly via positron emission tomography (PET), single photon emission computed tomography (SPECT), and advanced magnetic resonance imaging (MRI) modalities.

18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/Computerized Tomography (CT) is an important imaging modality in oncology, but its use in spinal cord assessment is limited due to a lack of baseline metabolic reference values. Regional spinal cord FDG uptake, especially in healthy populations, remains poorly defined, limiting accurate delineation between physiological and pathological uptake. The study aimed to quantify regional FDG uptake in the cervical, thoracic, and lumbar spinal cord in healthy adults, and evaluate associations between FDG uptake and demographic factors, including age, sex, body mass index (BMI), and inflammatory/metabolic biomarkers. A secondary aim was to apply artificial intelligence (AI)-driven segmentation to facilitate standardized region-of-interest extraction across spinal cord levels. This was a retrospective, cross-sectional observational study conducted using data from the CAMONA clinical trial at Odense University Hospital, Denmark. 76 healthy adult participants (mean age 44.66 ± 14.04 years; 53.9

This report describes the 18F-sodium fluoride (18F-NaF) and 18F-fluorodeoxyglucose (18F-FDG) PET/CT imaging of spinal instrumentation incidentally found in a 71-year-old male with extensive degenerative spinal disease. Hardware was noted at L5-S1, a common site of lumbar degeneration and cause of radiculopathy. 18F-NaF showed intense focal uptake at the instrumentation site, while 18F-FDG demonstrated minimal uptake. These findings suggest remodeling of bone (18F-NaF) at the site of instrumentation in the setting of benign physiological metabolic activity (18F-FDG). Other signs of structural deterioration were observed in the cervical and thoracic regions, such as osteophytes and ossification of the posterior longitudinal ligament. We present these findings in the context of a literature review of published studies that utilized 18F-NaF or 18F-FDG PET imaging for the assessment and monitoring of patients with spinal instrumentation.

OBJECTIVE:Imaging vertebral molecular activity with PET/computed tomography (CT) may enable earlier detection of degenerative diseases of the spine. This study aimed to evaluate physiological patterns of vertebral molecular activity and their association with degenerative risk factors with 18F-fluorodeoxyglucose (18F-FDG) and 18F-sodium fluoride (18F-NaF) PET/CT. METHODS:120 subjects (mean age 48.8 ± 14.1 years, 51% male) underwent 18F-FDG and 18F-NaF PET/CT imaging. The TotalSegmentator software was used to automatically generate regions of interest surrounding each vertebral body to quantify mean standardized uptake value (SUVmean) for each radiotracer, average Hounsfield Units, and volume. RESULTS:Cervical and lumbar 18F-FDG SUVmean exceeded thoracic uptake (P < 0.01). 18F-NaF activity was greatest in the lumbar spine, followed by the thoracic and the cervical regions (P < 0.01). 18F-FDG SUVmean was associated with age (ρ = 0.19, P = 0.03, cervical), BMI (ρ = 0.28-0.40, P < 0.01, all regions), bone density (ρ = -0.30, P = 0.01, cervical), and volume (ρ = -0.20, P = 0.02, cervical). 18F-NaF SUVmean correlated with age (ρ = 0.21 and -0.20, P ≤ 0.03 in cervical and lumbar regions, respectively), BMI (ρ = 0.23 and 0.26, P ≤ 0.01in thoracic and lumbar regions, respectively), bone density (ρ = 0.38, P < 0.01, lumbar), and volume (ρ = -0.30, P < 0.01, lumbar). Cervical 18F-FDG and 18F-NaF SUVmean were higher in females than males. CONCLUSION:18F-FDG and 18F-NaF PET/CT reveal distinct physiological patterns of vertebral molecular activity associated with degenerative risk factors, which may improve screening and prognostic methods for vertebral pathology.

Autism spectrum disorder (ASD) is a characteristically heterogeneous disorder, as multiple neurodevelopmental disorders are characterized by similar symptomology and behavior. Research has shown that individuals with ASD benefit from early intervention; neuroimaging data may reveal information that cannot be obtained from traditional behavioral analysis. This review discusses the use of structural MR imaging, functional MR imaging (fMR imaging), and PET in the detection of ASD. Larger datasets, standardized methods of collection and analysis, and more robust meta-analyses are required to implement the observed biomarkers and improve the lives of patients living with AUD.

Radiation-induced coronary artery disease (RI-CAD) is a significant cardiovascular complication for cancer survivors treated with thoracic radiation therapy (RT). Despite advances in RT techniques, exposure to the heart during treatment remains a critical factor influencing long-term cardiac outcomes, particularly in patients with breast and lung cancer. RI-CAD develops due to radiation-induced endothelial injury, inflammation, and accelerated atherosclerosis, presenting a unique and aggressive disease profile. This review explores the pathophysiology, risk factors, and diagnostic advancements for RI-CAD, emphasizing the role of PET in improving patient outcomes.

Intracranial atherosclerosis is a leading cause of stroke and cognitive dysfunction. Calcification of intracranial atherosclerotic plaques is commonly observed on noncontrast CT, yet structural imaging alone cannot visualize active microcalcifications characteristic of progressive atheroma. 18 F-NaF is an emerging PET radiotracer of vascular microcalcification that may enable the detection of such pathophysiology. In this report, we present molecular microcalcification of the left vertebral artery incidentally found on 18 F-NaF PET/CT of a 64-year-old man with risk factors for intracranial atherosclerosis.

Degenerative disc disease (DDD) is a common spinal condition characterized by the deterioration of intervertebral discs, leading to chronic back pain and reduced mobility. While magnetic resonance imaging (MRI) has long been the standard for late-stage DDD diagnosis, its limitations in early-stage detection prompt the exploration of advanced imaging methods. Positron emission tomography/computed tomography (PET/CT) using 18F- fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) has shown promise in identifying metabolic imbalances and age-related spinal degeneration, thereby complementing CT grading of the disease. The novel hybrid imaging modality PET/MRI provides new opportunities and are briefly discussed. The complex pathophysiology of DDD is dissected to highlight the role of genetic predisposition and lifestyle factors such as smoking and obesity. These etiological factors significantly impact the lumbosacral region, manifesting in chronic low back pain (LBP) and potential nerve compression. Traditional grading systems, like the Pfirrmann classification for MRI, are evaluated for their limitations in capturing the full spectrum of DDD. The potential to identify early disease processes and predict patient outcomes by the use of artificial intelligence (AI) is also briefly mentioned. Overall, the manuscript aims to spotlight advancements in imaging technologies for DDD, emphasizing their implications in refining both diagnosis and treatment strategies. The role of ongoing and future research is emphasized to validate these emerging techniques and overcome current limitations for more effective early detection and treatment.

RT is essential for the treatment of cancers; however, RIIs pose significant challenges in the clinical setting that require advanced imaging tools for optimal characterization. Cardiopulmonary PETCT-MRI imaging provides a novel avenue to visualize both acute and chronic damage from ionizing radiation, with quantitative PET providing a particularly valuable anatomic and structural complement to the metabolic changes seen in PET-CT, which further enhances the diagnostic process and accuracy with early and timely visualization of subclinical changes. Despite advances in recent imaging modalities, several challenges open the way for further research and exploration of clinical uses. Development of standardized protocols for PET metrics and the use of novel tracers tailored to individual pathologies may be crucial for maximizing diagnostic accuracy and widespread clinical practice for treatment across multiple organ systems. Future research can focus on the evolving applications of PET in injured tissues such as the neurovascular and gastrointestinal tissues. Although PET-CT-MRI still faces several limitations, such as accessibility and implementation, we expect the multi-modal integration of quantitative MRI with current PET/CT imaging will provide a more comprehensive diagnostic framework that will play a leading role in the prevention and early identification of RIIs to further improve patient's quality of life.

VaD is a significant cause of cognitive deterioration that is strongly associated with modifiable cardiovascular and atherosclerotic risk factors. PET imaging provides a novel avenue to visualize early-stage pathogenesis, characterized by potentially reversible neuronal and vascular changes that precede the onset of irreversible structural alterations and cognitive dysfunction. FDG PET captures patterns of metabolic activity in the brain that can aid in the identification of VaD and its subtypes, whereas NaF PET may capture subclinical atherosclerosis in the major arterial beds supplying the brain. Though PET faces several limitations, such as accessibility, implementation, and radiation exposure, we believe that the multi- modal integration of PET imaging will permit a comprehensive understanding of VaD pathophysiology and play a leading role in the future study of therapeutics.