A Study of the Feasibility of FDG-PET/CT to Systematically Detect and Quantify Differential Metabolic Effects of Chronic Tobacco Use in Organs of the Whole Body-A Prospective Pilot Study

Brain Glucose Metabolism as a Readout of the Central Nervous System Impact of Cigarette Smoke Exposure and Withdrawal and the Effects of NFL-101, as an Immune-Based Drug Candidate for Smoking Cessation Therapy

Neuroimaging biomarkers are needed to investigate the impact of smoking withdrawal on brain function. NFL-101 is a denicotinized aqueous extract of tobacco leaves currently investigated as an immune-based smoking cessation therapy in humans. However, the immune response to NFL-101 and its ability to induce significant changes in brain function remain to be demonstrated. Brain glucose metabolism was investigated using [18F]fluoro-deoxy-glucose ([18F]FDG) PET imaging in a mouse model of cigarette smoke exposure (CSE, 4-week whole-body inhalation, twice daily). Compared with control animals, the relative uptake of [18F]FDG in CSE mice was decreased in the thalamus and brain stem (p < 0.001, n = 14 per group) and increased in the hippocampus, cortex, cerebellum, and olfactory bulb (p < 0.001). NFL-101 induced a humoral immune response (specific IgGs) in mice and activated human natural-killer lymphocytes in vitro. In CSE mice, but not in control mice, single-dose NFL-101 significantly increased [18F]FDG uptake in the thalamus (p < 0.01), thus restoring normal brain glucose metabolism after 2-day withdrawal in this nicotinic receptor-rich region. In tobacco research, [18F]FDG PET imaging provides a quantitative method to evaluate changes in the brain function associated with the withdrawal phase. This method also showed the CNS effects of NFL-101, with translational perspectives for future clinical evaluation in smokers.

Preoperative Computed Tomography Morphological Features Indicative of Incisional Hernia Formation After Abdominal Surgery

OBJECTIVE

To investigate key morphometric features identifiable on routine preoperative computed tomography (CT) imaging indicative of incisional hernia (IH) formation following abdominal surgery.

BACKGROUND

IH is a pervasive surgical disease that impacts all surgical disciplines operating in the abdominopelvic region and affecting 13% of patients undergoing abdominal surgery. Despite the significant costs and disability associated with IH, there is an incomplete understanding of the pathophysiology of hernia.

METHODS

A cohort of patients (n=21,501) that underwent colorectal surgery was identified, and clinical data and demographics were extracted, with a primary outcome of IH. Two datasets of case-control matched pairs were created for feature measurement, classification, and testing. Morphometric linear and volumetric measurements were extracted as features from anonymized preoperative abdominopelvic CT scans. Multivariate Pearson testing was performed to assess correlations among features. Each feature's ability to discriminate between classes was evaluated using 2-sided paired t testing. A support vector machine was implemented to determine the predictive accuracy of the features individually and in combination.

RESULTS

Two hundred and twelve patients were analyzed (106 matched pairs). Of 117 features measured, 21 features were capable of discriminating between IH and non-IH patients. These features are categorized into three key pathophysiologic domains: 1) structural widening of the rectus complex, 2) increased visceral volume, 3) atrophy of abdominopelvic skeletal muscle. Individual prediction accuracy ranged from 0.69 to 0.78 for the top 3 features among 117.

CONCLUSIONS

Three morphometric domains identifiable on routine preoperative CT imaging were associated with hernia: widening of the rectus complex, increased visceral volume, and body wall skeletal muscle atrophy. This work highlights an innovative pathophysiologic mechanism for IH formation hallmarked by increased intra-abdominal pressure and compromise of the rectus complex and abdominopelvic skeletal musculature.

Impact of tobacco and/or nicotine products on health and functioning: a scoping review and findings from the preparatory phase of the development of a new self-report measure

BACKGROUND

Measuring self-reported experience of health and functioning is important for understanding the changes in the health status of individuals switching from cigarettes to less harmful tobacco and/or nicotine products (TNP) or reduced-risk products (RRP) and for supporting tobacco harm reduction strategies.

METHODS

This paper presents insights from three research activities from the preparatory phase of the development of a new self-report health and functioning measure. A scoping literature review was conducted to identify the positive and negative impact of TNP use on health and functioning. Focus groups (n = 29) on risk perception and individual interviews (n = 40) on perceived dependence in people who use TNPs were reanalyzed in the context of health and functioning, and expert opinion was gathered from five key opinion leaders and five technical consultants.

RESULTS

Triangulating the findings of the review of 97 articles, qualitative input from people who use TNPs, and expert feedback helped generate a preliminary conceptual framework including health and functioning and conceptually-related domains impacted by TNP use. Domains related to the future health and functioning measurement model include physical health signs and symptoms, general physical appearance, functioning (physical, sexual, cognitive, emotional, and social), and general health perceptions.

CONCLUSIONS

This preliminary conceptual framework can inform future research on development and validation of new measures for assessment of overall health and functioning impact of TNPs from the consumers' perspective.

Prevalence of overweight and obesity and associated risk factors among adult residents of northwest China: a cross-sectional study

OBJECTIVE

Overweight and obesity have been shown to be related to multiple chronic conditions, leading to a heavy economic burden on society throughout the world. This study aims to estimate the prevalence of overweight and obesity and determine potential influencing factors among adults in Xinjiang, northwest China.

DESIGN

A community-based observational study.

SETTING

The First Affiliated Hospital of Xinjiang Medical University.

METHODS

In total, 14 618 adult participants (7799 males; 6819 females) aged over 35 years were recruited from the Cardiovascular Risk Survey conducted in 2010. Data were obtained from face-to-face interviews and physical examinations. The sample was used to estimate the prevalence of overweight (body mass index (BMI) 24-28 kg/m²) and obesity (BMI ≥28 kg/m²) in Xinjiang Province. Influencing factors were analysed based on statistical methods.

RESULTS

In Xinjiang Province, the overall prevalence of overweight was 36.5% (male 40.1%; female 33.4%), and the prevalence of obesity was 26.5% (male 27.2%; female 25.8%). The prevalence of both overweight and obesity were higher in women than in men (p<0.001). The main influencing factors for overweight and obesity were sex, age, race, marital status, education level, occupation, smoking, drinking, hypertension, diabetes and dyslipidaemia (p<0.05).

CONCLUSIONS

This study estimated that the prevalence of overweight and obesity among adult residents of Xinjiang Province, northwest China, was high. These data suggest that efforts related to the prevention and control of overweight and obesity should be a public health priority in northwest China.

Performance Evaluation of a Semi-automated Method for [18F]FDG Uptake in Abdominal Visceral Adipose Tissue

PURPOSE

Severity of abdominal obesity and possibly levels of metabolic activity of abdominal visceral adipose tissue (VAT) are associated with an increased risk for cardiovascular disease (CVD). In this context, the purpose of the current study was to evaluate the reproducibility and repeatability of a semi-automated method for assessment of the metabolic activity of VAT using 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET)/x-ray computed tomography (CT).

PROCEDURES

Ten patients with lung cancer who underwent two baseline whole-body [¹⁸F]FDG PET/low-dose (LD) CT scans within 1 week were included. Abdominal VAT was automatically segmented using CT between levels L1-L5. The initial CT-based segmentation was further optimized using PET data with a standardized uptake value (SUV) threshold approach (range 1.0-2.5) and morphological erosion (range 0-5 pixels). The [¹⁸F]FDG uptake in SUV that was measured by the automated method was compared with manual analysis. The reproducibility and repeatability were quantified using intraclass correlation coefficients (ICCs).

RESULTS

The metabolic assessment of VAT on [¹⁸F]FDG PET/LDCT scans expressed as SUV_mean, using an automated method showed high inter and intra observer (all ICCs > 0.99) and overall repeatability (ICC = 0.98). The manual method showed reproducible inter observer (all ICCs > 0.92), but less intra observer (ICC = 0.57) and less overall repeatability (ICC = 0.78) compared with the automated method.

CONCLUSIONS

Our proposed semi-automated method provided reproducible and repeatable quantitative analysis of [¹⁸F]FDG uptake in VAT. We expect this method to aid future research regarding the role of VAT in development of CVD.

Increased white matter metabolic rates in autism spectrum disorder and schizophrenia

Both autism spectrum disorder (ASD) and schizophrenia are often characterized as disorders of white matter integrity. Multimodal investigations have reported elevated metabolic rates, cerebral perfusion and basal activity in various white matter regions in schizophrenia, but none of these functions has previously been studied in ASD. We used ¹⁸fluorodeoxyglucose positron emission tomography to compare white matter metabolic rates in subjects with ASD (n = 25) to those with schizophrenia (n = 41) and healthy controls (n = 55) across a wide range of stereotaxically placed regions-of-interest. Both subjects with ASD and schizophrenia showed increased metabolic rates across the white matter regions assessed, including internal capsule, corpus callosum, and white matter in the frontal and temporal lobes. These increases were more pronounced, more widespread and more asymmetrical in subjects with ASD than in those with schizophrenia. The highest metabolic increases in both disorders were seen in the prefrontal white matter and anterior limb of the internal capsule. Compared to normal controls, differences in gray matter metabolism were less prominent and differences in adjacent white matter metabolism were more prominent in subjects with ASD than in those with schizophrenia. Autism spectrum disorder and schizophrenia are associated with heightened metabolic activity throughout the white matter. Unlike in the gray matter, the vector of white matter metabolic abnormalities appears to be similar in ASD and schizophrenia, may reflect inefficient functional connectivity with compensatory hypermetabolism, and may be a common feature of neurodevelopmental disorders.

Global and regional brain hypometabolism on FDG-PET in treated HIV-infected individuals

OBJECTIVE

To quantitatively measure brain glucose metabolism in treated HIV-positive individuals with [¹⁸F]-labeled fluorodeoxyglucose (FDG) PET/CT.

METHODS

We performed a cross-sectional comparison of FDG uptake in 47 treated HIV+ individuals, 10 age-matched controls (HIV-) sharing many of the comorbid conditions seen in the HIV+ group, and 19 age-matched healthy controls (HCs). We compared whole-brain (WB) and regional FDG standardized uptake values (SUVs) of select subcortical/central structures among the groups and correlated the values to clinical and neuropsychological assessments. A variable selection model was used to predict SUVs in HIV+ (n = 47) and in combined HIV+ and HIV- participants (n = 57).

RESULTS

We found lower WB SUVmax in HIV+ participants compared to HCs but not to HIV- participants. Among the relative SUVmean measurements (regional SUVmean/WB SUVmean), only relative thalamic uptake values were lower in HIV+ compared to HIV- participants. When HIV+ and HIV- participants were grouped, cardiovascular disease risk scores best predicted WB SUVmean and SUVmax, while HIV status best predicted thalamic relative SUVmean.

CONCLUSIONS

We identified an important role for cardiovascular disease in neuronal loss/dysfunction, as measured by FDG-PET, in treated HIV+ patients. This underscores the need for shifting the focus of clinical intervention in this vulnerable population from HIV effects alone to a wider set of comorbid conditions, mainly cardiovascular disease. Only the thalamus showed significantly lower relative uptake in the HIV+ compared to the HC and HIV- groups. This needs to be further evaluated for underlying pathophysiology and potential association with memory, executive functioning, and attention deficits seen in the HIV+ population.

Regional Variation in Skeletal Muscle and Adipose Tissue FDG Uptake Using PET/CT and Their Relation to BMI

RATIONALE AND OBJECTIVES

Skeletal muscle metabolism is a primary contributor to whole-body energy expenditure. Currently, methods to measure changes in skeletal muscle metabolism in vivo are limited. Our objectives were to characterize the regional variation in skeletal muscle and adipose tissue (AT) FDG uptake as a surrogate for glycolytic metabolism using ¹⁸F-2-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in healthy men and to correlate these findings to body mass index (BMI).

MATERIALS AND METHODS

Eighteen healthy men were enrolled and underwent FDG-PET/CT. The mean standardized uptake value of 14 skeletal muscles and two AT regions was measured and linear regression analysis was performed to identify metabolic predictors of BMI.

RESULTS

FDG-PET/CT reliably detected changes in skeletal muscle and AT depot metabolic activity based on location. The most metabolically active muscles were those used for posture and breathing, which have the highest percentage of reported type I muscle myofiber content. Visceral AT tended to have a higher FDG uptake than subcutaneous AT. The mean standardized uptake value of VAT, pectoralis major, and gluteus maximus muscles accounted for 64% of the variance in BMI.

CONCLUSIONS

FDG-PET/CT can be used to quantify the regional variation in glucose metabolism of multiple skeletal muscle groups and AT depots.