Differences in muscle composition and functionality: Exploring CT anatomical points and SARC-F components.

PURPOSE: Our study aimed to 1) investigate the differences of muscle parameters in relation to each SARC-F component/question; and 2) explore the relationship between SARC-F score with these muscle parameters using various landmarks derived from computed tomography (CT) scans of patients with cancer. METHODS: This study is a cross-sectional analysis of a cohort comprised of consecutive patients with cancer, displaying CT scans. SARC-F questionnaire was utilized as a proxy for muscle functionality, with a score ≥4 indicating a poor status. Muscle assessment via CT measurements was performed using single cross-sectional images at the level of the third lumbar vertebrae (L3) in the abdominal region, the thigh region, and the total gluteal region at the level of the second sacral vertebrae. Skeletal muscle (SM) cross-sectional area, SM index (normalized to height2), and SM radiodensity (SMD) were evaluated for all anatomical landmarks. RESULTS: A total of 128 patients were included in this analysis (53.1% females, 61.7% older adults). Patients with SARC-F scores ≥4 demonstrated significantly lower values of SMD across all landmarks assessed. Those reporting difficulties related to strength (P = 0.039), requiring assistance in walking (P = 0.033), and climbing stairs (P = 0.012) exhibited significantly lower SMD values at the L3 landmark. At gluteus and thigh levels, only patients experiencing difficulty climbing stairs (P = 0.012) showed significantly lower values of SMD. Only SMD at gluteus level was independently associated with SARC-F score (ßadjusted -0.09, 95% CI -0.16 to -0.02). CONCLUSIONS: Our findings suggest that individuals with poor muscle composition may experience a higher risk of sarcopenia/poor muscle functionality.

Association between body composition phenotypes and treatment toxicity in women with cervical cancer undergoing chemoradiotherapy.

OBJECTIVE: To identify whether there is an association between body composition phenotypes and toxicity to chemoradiotherapy in women with cervical cancer. METHODS: This is a prospective cohort study that included 330 adult patients with cervical cancer treated with chemoradiotherapy. Computed tomography images were used to assess skeletal muscle index (SMI) and radiodensity (SMD), total adipose tissue index, and visceral adipose tissue index. Chemoradiotherapy toxicity was assessed weekly, and toxicity-induced modification of treatment (TIMT) was considered as any severe adverse event resulting in treatment interruption, delay, or dose reduction. RESULTS: Approximately 45% of the patients presented at least one unfavorable body composition parameter (lower SMI, lower SMD, higher total adipose tissue index, or higher visceral adipose tissue index), 23% had two conditions, and 3% had three conditions. The incidence of toxicity ≥ grade 3 and TIMT was 55% and 30%, respectively. For adverse events ≥ grade 3, lower SMI was the determining factor for worse outcomes when evaluated alone or combined with lower SMD and normal adiposity. All body composition phenotypes were associated with TIMT, increasing the risk when both conditions were present. CONCLUSIONS: Lower SMI was an independent factor for the higher number of adverse events, as it remained a risk factor when analyzed in isolation or in association with adipose tissue. Women with excess adipose tissue associated with lower muscle mass had a risk approximately 4 times higher of delaying or interrupting chemoradiotherapy. Furthermore, for the sum of unfavorable conditions, there was a progressive increase in the risk of TIMT.

Myosteatosis and muscle loss impact liver transplant outcomes in male patients with hepatocellular carcinoma.

BACKGROUND: Sarcopenia is associated with unfavourable long-term survival in patients undergoing liver transplantation (LT) for hepatocellular carcinoma (HCC). However, the impact of myosteatosis and muscle loss on patient prognosis has not been investigated. METHODS: Seven hundred fifty-six HCC patients who received LT at 3 transplant centres were included. Computed tomography (CT) images of recipients were collected to measure skeletal muscle index (SMI) and skeletal muscle radiodensity (SMRA). The impact of myosteatosis on the prognosis of sarcopenic and non-sarcopenic patients was studied separately. Muscle status was evaluated based on the presence of sarcopenia and myosteatosis. The muscle loss of 342 males was calculated as the relative change of SMI between pre- and post-LT evaluations. Cox regression models were used to identify predictors of overall survival (OS) and recurrence-free survival (RFS). RESULTS: The study comprised 673 males and 83 females. The median follow-up time was 31 months (interquartile range, 19-43 months). Prior to LT, 267 (39.7%) and 187 (27.8%) males were defined as sarcopenic (low-SMI) and myosteatotic (low-SMRA), respectively. For sarcopenic recipients, the presence of myosteatosis was followed by a 23.6% decrease in 5 year OS (P < 0.001) and a 15.0% decrease in 5 year RFS (P = 0.014). Univariate and multivariate analyses revealed that muscle status was an independent predictor of OS [hazard ratio (HR), 1.569; 95% confidence interval (CI), 1.317-1.869; P < 0.001] and RFS (HR, 1.369; 95% CI, 1.182-1.586; P < 0.001). Postoperatively, a muscle loss >14.2% was an independent risk factor for poor OS (HR, 2.286; 95% CI, 1.358-3.849; P = 0.002) and RFS (HR, 2.219; 95% CI, 1.418-3.471; P < 0.001) in non-sarcopenic recipients (N = 209). CONCLUSIONS: Pre-transplant myosteatosis aggravated the adverse impact of sarcopenia on liver transplant outcomes in male HCC patients. Post-transplant muscle loss might assist in prognostic stratification of recipients without pre-existing sarcopenia, intriguing new insights into individualized management.

Influence of periapical lesion volume on the radiodensity of surrounding bone: A CBCT study.

Aim: This study assesses if the size of periapical lesions has an effect on the bone immediately peripheral to an apical lesion. Methods: Cone-beam computed tomography (CBCT) images of 271 periapical lesions were analyzed using Mimics Research™ to determine the CBCT periapical lesion volume index (CBCTPAVI) score, along with the radiodensity of the lesion, lesion border, and surrounding bone in 0.5 mm increments up to 2.0 mm peripheral to the apical lesion. The one-way analysis of variance was used to assess for significant differences in the radiodensity of the lesion, border, and peripheral bone, as well as differences among CBCTPAVI scores. Results: The radiodensity of bone peripheral to the apical lesion increased significantly up to 1.0 mm around the lesion's perimeter. In addition, lesions with higher CBCTPAVI scores showed a significantly greater difference in the radiodensity from the lesion to the lesion border and the peripheral bone, compared to lesions with smaller CBCTPAVI scores. Conclusions: This study for the first time shows the influence of periapical lesion size on the radiodensity of bone peripheral to an apical lesion. Variations in radiodensity at the perimeter of a periapical lesion can be influenced by the size of the lesion, possibly indicating differences in defense response. Knowledge of these phenomena may provide information on bone healing and enhance our understanding of bone peripheral to a periapical lesion.

Glucose metabolism and radiodensity of abdominal adipose tissue: A 5-year longitudinal study in a large PET cohort.

OBJECTIVE: 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) allows noninvasive assessment of glucose metabolism and radiodensity in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). We aimed to address the effects of ageing and metabolic factors on abdominal adipose tissue. DESIGN, PATIENTS AND MEASUREMENTS: We retrospectively analyzed data from 435 healthy men (mean 42.8 years) who underwent a health check-up programme twice, at baseline and the 5-year follow-up. The mean standardized uptake value (SUV) was measured using SAT and VAT and divided by the liver SUV. The mean Hounsfield units (HU) of the SAT and VAT were measured from the CT scans. The effects of clinical variable clusters on SUVR were investigated using Bayesian hierarchical modelling; metabolic cluster (BMI, waist-to-hip ratio, fat percentage, muscle percentage*-1, HOMA-IR), blood pressure (systolic, diastolic), glucose (fasting plasma glucose level, HbA1c) and C-reactive protein. RESULTS: All the clinical variables changed during the 5-year follow-up period. The SUVR and HU of the VAT increased during follow-up; however, those of the SAT did not change. SUVR and HU were positively correlated with both VAT and SAT. SAT and VAT SUVR were negatively associated with metabolic clusters. CONCLUSIONS: Ageing led to increased glucose metabolism and radiodensity in VAT, but not in SAT. VAT may reflect the ageing process more directly than SAT. Glucose metabolism was higher and radiodensity was lower in VAT than in SAT, probably owing to differences in gene expression and lipid density. Both glucose metabolism and radiodensity of VAT and SAT reflect metabolic status.

Thigh muscle by CT images as a predictor of mortality in patients with newly diagnosed colorectal cancer.

This study aimed to evaluate the prognostic value of thigh muscle assessed by CT images to predict overall mortality in patients with colorectal cancer (CRC). This was a multicenter cohort study including adults (≥ 18 years old) newly diagnosed with CRC, who performed a diagnostic computed tomography (CT) exam including thigh regions. CT images were analyzed to evaluate skeletal muscle (SM in cm2), skeletal muscle index (SMI in cm2/m2), and skeletal muscle density (SMD in HU). Muscle abnormalities (low SM, SMI, and SMD) were defined as the values below the median by sex. Kaplan-Meyer curves and hazard ratios (HRs) for low SM, SMI and SMD were evaluated for overall mortality, stratified by sex. A total of 257 patients were included in the final analysis. Patients' mean age was 62.6 ± 12.1 years, and 50.2% (n = 129) were females. In males, low thigh SMI was associated with shorter survival (log-rank P = .02). Furthermore, this low thigh SMI (cm2/m2) was independently associated with higher mortality rates (HR adjusted 2.08, 95% CI 1.03-4.18). Our additional findings demonstrated that low SMD was independently associated with overall mortality among early-stage patients (I-III) (HR adjusted 2.78, 95% CI 1.26-6.15).

Interpretable machine learning model based on clinical factors for predicting muscle radiodensity loss after treatment in ovarian cancer.

PURPOSE: Muscle radiodensity loss after surgery and adjuvant chemotherapy is associated with poor outcomes in ovarian cancer. Assessing muscle radiodensity is a real-world clinical challenge owing to the requirement for computed tomography (CT) with consistent protocols and labor-intensive processes. This study aimed to use interpretable machine learning (ML) to predict muscle radiodensity loss. METHODS: This study included 723 patients with ovarian cancer who underwent primary debulking surgery and platinum-based chemotherapy between 2010 and 2019 at two tertiary centers (579 in cohort 1 and 144 in cohort 2). Muscle radiodensity was assessed from pre- and post-treatment CT acquired with consistent protocols, and a decrease in radiodensity ≥ 5% was defined as loss. Six ML models were trained, and their performances were evaluated using the area under the curve (AUC) and F1-score. The SHapley Additive exPlanations (SHAP) method was applied to interpret the ML models. RESULTS: The CatBoost model achieved the highest AUC of 0.871 (95% confidence interval, 0.870-0.874) and F1-score of 0.688 (95% confidence interval, 0.685-0.691) among the models in the training set and outperformed in the external validation set, with an AUC of 0.839 and F1-score of 0.673. Albumin change, ascites, and residual disease were the most important features associated with a higher likelihood of muscle radiodensity loss. The SHAP force plot provided an individualized interpretation of model predictions. CONCLUSION: An interpretable ML model can assist clinicians in identifying ovarian cancer patients at risk of muscle radiodensity loss after treatment and understanding the contributors of muscle radiodensity loss.

Association of muscle mass and radiodensity assessed by chest CT with all-cause and cardiovascular mortality in hemodialysis patients.

PURPOSE: This study investigates the prognostic value of skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD) measured by chest CT in relation to all-cause and cardiovascular disease (CVD) mortality among hemodialysis (HD) patients. METHODS: A retrospective study was conducted from January 2015 to December 2021 involving HD patients at a dialysis center. Chest CT scans at the twelfth thoracic vertebra level (T12) were analyzed to assess SMI and SMD. Sex-specific cut-off values for two metrics were determined using maximally selected rank statistics. Hazard ratios (HRs) were calculated to evaluate the associations of SMI and SMD with mortality. The discrimination of prognostic models was also compared. RESULTS: The study included 603 patients with a median age of 58 years. Of these, 187 (31.0%) patients with SMI < 30.00 cm2/m2 (male) or < 25.04 cm2/m2 (female) and 192 (31.8%) patients with SMD < 32.25 HU (male) or < 30.64 HU (female) were categorized as lower SMI and SMD, respectively. Over a median follow-up of 3.8 years, 144 deaths occurred. Multivariate Cox regression analysis showed that lower SMI and SMD were independently associated with all-cause mortality (SMI: HR = 1.47, 95% CI 1.03-2.10; SMD: HR = 1.75, 95% CI 1.20-2.54) and CVD mortality (SMI: HR = 1.74, 95% CI 1.03-2.94; SMD: HR = 1.72, 95% CI 1.02-2.95). Adding SMI and SMD to the established risk model improved the C-index from 0.82 to 0.87 (P < 0.001). Decision curve analysis showed that the prognostic model incorporating both SMI and SMD offered the highest net benefit for predicting all-cause mortality. CONCLUSIONS: Muscle metrics derived from CT scans at T12 level provide valuable prognostic information which could enhance the role of chest CT in muscle assessment among HD patients.

Inflammation, but not skeletal muscle index, is associated with coronavirus disease 2019 mortality in patients with cancer.

BACKGROUND & AIMS: Patients with cancer and coronavirus disease 2019 (COVID-19) have characteristics that can cause the most severe forms of the disease and higher mortality. We aimed to assess the association between computed tomography (CT)-derived muscle abnormalities, anthropometric parameters, inflammation, and mortality in patients with cancer and COVID-19. METHODS: This retrospective study included patients with cancer and COVID-19 admitted between March 1st and December 31st, 2020. All information was collected from medical records (clinical and nutritional parameters, serum albumin, and C-reactive protein [CRP]). Weight loss and body mass index (BMI) were assessed using Global Leadership Initiative on Malnutrition phenotypic criteria. Skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD) at the fourth thoracic vertebra level were assessed using computed tomography scans. RESULTS: This study included 80 patients (61% men, mean age: 58 ± 17 years). Of the patients analyzed, 49% had weight loss >5%, and 14% had low BMI. The median length of hospital stay was 7 (interquartile range: 4-14 days), 27% needed mechanical ventilation, 34% died as a direct consequence of COVID-19 infection and 15% to complications associated with cancer condition. In multivariate logistic regression analysis, low SMI was associated with increased in-hospital mortality [odds ratio (OR): 4.81; 95% confidence interval (95% CI): 1.63; 14.2; p = 0.005), while CRP was associated with COVID-19-related mortality (OR: 1.08; 95% CI: 1.01; 1.15, p = 0.018). CONCLUSION: SMI independently predicts in-hospital mortality in patients with cancer and COVID-19. Additionally, an independent association was observed between CRP and mortality specifically related to COVID-19.

Tumor metabolic activity is associated with subcutaneous adipose tissue radiodensity and survival in non-small cell lung cancer.

BACKGROUND: Cachexia-associated body composition alterations and tumor metabolic activity are both associated with survival of cancer patients. Recently, subcutaneous adipose tissue properties have emerged as particularly prognostic body composition features. We hypothesized that tumors with higher metabolic activity instigate cachexia related peripheral metabolic alterations, and investigated whether tumor metabolic activity is associated with body composition and survival in patients with non-small-cell lung cancer (NSCLC), focusing on subcutaneous adipose tissue. METHODS: A retrospective analysis was performed on a cohort of 173 patients with NSCLC. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scans obtained before treatment were used to analyze tumor metabolic activity (standardized uptake value (SUV) and SUV normalized by lean body mass (SUL)) as well as body composition variables (subcutaneous and visceral adipose tissue radiodensity (SAT/VAT radiodensity) and area; skeletal muscle radiodensity (SM radiodensity) and area). Subjects were divided into groups with high or low SAT radiodensity based on Youden Index of Receiver Operator Characteristics (ROC). Associations between tumor metabolic activity, body composition variables, and survival were analyzed by Mann-Whitney tests, Cox regression, and Kaplan-Meier analysis. RESULTS: The overall prevalence of high SAT radiodensity was 50.9% (88/173). Patients with high SAT radiodensity had shorter survival compared with patients with low SAT radiodensity (mean: 45.3 vs. 50.5 months, p = 0.026). High SAT radiodensity was independently associated with shorter overall survival (multivariate Cox regression HR = 1.061, 95% CI: 1.022-1.101, p = 0.002). SAT radiodensity also correlated with tumor metabolic activity (SULpeak rs = 0.421, p = 0.029; SUVpeak rs = 0.370, p = 0.048). In contrast, the cross-sectional areas of SM, SAT, and VAT were not associated with tumor metabolic activity or survival. CONCLUSION: Higher SAT radiodensity is associated with higher tumor metabolic activity and shorter survival in patients with NSCLC. This may suggest that tumors with higher metabolic activity induce subcutaneous adipose tissue alterations such as decreased lipid density, increased fibrosis, or browning.

Strength-to-muscle radiodensity: A potential new index for muscle quality.

BACKGROUND & AIMS: Although it is widely recognized that muscle quality significantly influences adverse outcomes in patients with cancer, the precise definition of muscle quality remains elusive. The muscle quality index (MQI), also known as muscle-specific strength, is a relatively recent functional concept of muscle quality. It is obtained through the ratio of muscle strength to muscle mass, but its predictive value in patients with cancer remains unknown. In this study, we explored the prognostic significance of MQI in patients with cancer. Furthermore, we introduce and assess the prognostic potential of a novel muscle quality metric: the strength-to-muscle-radiodensity index (SMRi). METHODS: A secondary analysis was conducted on a prospective cohort study. CT scans were opportunistically used to assess body composition parameters, including skeletal muscle mass (SM in cm2) and muscle radiodensity (SMD in HU) at the third lumbar vertebra (L3). Handgrip strength (HGS) was measured. MQICT was calculated using the ratio of HGS to SM (cm2). SMRi was calculated as the ratio of HGS to SMD (HU). For analysis purposes, low MQICT and SMRi were defined using two approaches: statistical cutoffs associated with survival, and median-based distribution data. RESULTS: A total of 250 patients were included (52.8% females, 52% adults, 20-90 years). Gastrointestinal tumors and stage III-IV were the most frequent diagnosis and stages. SMRi and MQICT were strongly positively correlated (ρ = 0.71 P < 0.001). Individual components of MQICT and SMRi were also positively correlated. Patients with both low MQICT and SMRi had shorter survival (log-rank P = 0.023 and P = 0.003, respectively). When applying median distribution cutoffs, SMRi emerged as the most accurate predictor of mortality (HR adjusted 3.18, 95% CI 1.50 to 6.75, C-index: 0.71), when compared to MQICT (HR adjusted 1.49, 95% CI 0.77 to 2.87, C-index: 0.68). CONCLUSION: This study introduces the concept and potential prognostic significance of the SMRi. The physiological and clinical implications of this new index warrant further investigation across a spectrum of diseases, including cancer.

Correlation of 18F-sodium fluoride uptake and radiodensity in extraosseous metastases of medullary thyroid carcinoma.

Objective: Although 18F-sodium fluoride (18F-NaF) uptake is frequently observed in extraosseous metastases of medullary thyroid carcinoma (MTC) with calcification, itcan also occur in metastatic sites without visible calcium deposition, leading to the hypothesis that visually undetectable calcium accumulation may be responsible for this uptake. The aim of this study was to indirectly support this hypothesis by analyzing the correlation between the degree of 18F-NaF uptake and radiodensity in extraosseous MTC metastases, since calcium deposition can increase attenuation even when not visually detectable. Subjects and methods: Extraosseous metastatic lesions of 15 patients with MTC were evaluated using 18F-NaF positron-emission tomography (PET)/computed tomography (CT)and segmented by levels of standardized uptake value (SUV). The correlation between mean SUV and mean Hounsfield unit (HU) values was assessed for the entire group of segments and for two subgroups with different mean HU values. Results: Very high correlations were observed between mean SUV and mean HU values for both the entire group of segments and the subgroup with a mean HU value greater than 130 (p = 0.92 and p = 0.95, respectively; p < 0.01). High correlation (p = 0.71) was also observed in the subgroup with mean HU values ranging from 20 to 130 (p < 0.01). Conclusion: The findings of the present study suggest that there is an association between 18F-NaF uptake and calcium deposition in extraosseous metastasesof MTC, supporting the hypothesis that visually undetectable calcium accumulation may be responsible for 18F-NaF uptake in regions without visible calcium deposition.

Mapping the Spatial Evolution of Proximal Femur Osteoporosis: A Retrospective Cross-Sectional Study Based on CT Scans.

Purpose: The purpose of this study was to quantify the modifications occurring in osteoporosis at the level of the human proximal femur throughout the trabecular structure, along with the identification of certain anatomic regions preferentially affected by osteoporosis. Another goal was to map the evolution of the radiodensity of the trabecular bone as osteoporosis progresses to an advanced stage. Methods: The study included CT scans (right femur) from 51 patients, out of which 40 had various degrees of osteoporosis, but no other local pathology. Ten regions of interest in two orthogonal slices have been identified and the differences in radiodensity as well as their evolution have been statistically analyzed in terms of relative and absolute changes. Results: A detailed spatial map showing the evolution of osteoporosis was obtained. As osteoporosis evolved, the relative decrease in radiodensity was inversely correlated to the radiodensity of the healthy bone. In particular, the region covering the Ward triangle decreased the most, by an average 61-62% in osteopenia and 101-106% in advanced osteoporosis, while the principal compressive group was affected the least, showing a decrease by an average 14-15% in osteopenia and 29-32% in advanced osteoporosis. The absolute decrease in radiodensity was not correlated to the radiodensity of the healthy bone and was shifted to the inferior-posterior edge of the femur. Inside the femoral head, the upper region was affected the most in absolute terms, while the greater trochanter was less affected than the femoral neck. The maximum metaphyseal cortical bone density was unaffected by the progression of osteoporosis. Conclusion: Significant differences were noticed in terms of the absolute and relative osteoporotic changes in radiodensity related to different anatomical regions of the human femoral bone. These differences become more pronounced as the disease progresses.

Complexed amino acid minerals vs. bis-glycinate chelated minerals: Impact on the performance of old laying hens.

The present study was to evaluate the effect of trace minerals (Zn, Mn, and Cu) from complexed amino acid minerals (ZMCAA) and bis-glycinate chelated minerals (ZMCGly) in laying hen diets on performance, internal and external egg quality, yolk mineral deposition, intestinal morphometry, and bone characteristics. From 78 to 98 weeks of age, 400 White LSL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per treatment. Treatments were distributed in a 2 × 2 factorial arrangement using either Zn, Mn, and Cu of ZMCAA or ZMCGly source at 2 levels: low (20, 20, and 3.5 mg/kg of Zn, Mn, and Cu, respectively) or high (40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively). The analysis of variance was performed, and in cases where differences were observed, the means were compared using Tukey's test (P < 0.05). The source and level of trace mineral supplementation had a significant impact on the performance of laying hens. Hens fed ZMCAA had higher egg production (P = 0.01), egg weight (P = 0.02), egg mass (P = 0.01), and lower feed conversion ratio (P = 0.05) compared to those fed ZMCGly. The ZMCAA supplementation showed higher albumen height (P = 0.01), albumen weight (P = 0.01), and eggshell thickness (P < 0.01). The deposition of Zn (P < 0.01), Mn (P < 0.01), and Cu (P < 0.01) in the egg yolk was greater for hens received ZMCAA. Tibia weight (P = 0.04) and bone densitometry (P < 0.01) in the tibia were higher with ZMCAA supplementation. In the small intestine, ZMCAA resulted in longer villi (P = 0.02) and shorter crypt depth (P = 0.01) in the duodenum. Jejunum and ileum measurements were influenced by the level and source of trace minerals (P < 0.05). Laying hens fed ZMCAA exhibited superior performance, egg quality, deposition of trace minerals in the egg yolk, and bone density compared to hens fed ZMCGly. In this study, older laying hens supplemented with ZMCAA at lower levels demonstrated adequate levels of supplementation.

Factors associated with variability in skeletal muscle radiodensity in patients with metastatic cancer.

OBJECTIVES: This study aimed to explore factors associated with skeletal muscle radiodensity (SMD) variability in patients with metastatic cancer. METHODS: This study included 393 patients (median age 61 y, 70% women) who had computed tomography (CT) scans within 30 days of inclusion in the study. SMD was evaluated from CT by averaging the Hounsfield unit value of the total muscle area. Skeletal muscle index (SMI), visceral adipose tissue index (VATI), subcutaneous adipose tissue index (SATI), and total adipose tissue index (TATI) were also assessed by CT. Additionally, age, sex, race/skin color, disease characteristics, comorbidities, inflammatory markers, handgrip strength (HGS), and body mass index (BMI) were recorded and evaluated in the linear regression analysis to identify factors associated with SMD variability. RESULTS: Multivariate explanatory models having SMD as an independent variable were performed and included BMI (model 1, r2 = 0.699), TATI (model 2, r2 = 0.712) or VATI and SATI (model 3, r2 = 0.706) in addition to age, race/skin color, tumor site, kidney disease, serum albumin, HGS, and SMI as dependent variables. For all models, lower SMD was associated with higher age, BMI, and adiposity measurements, kidney disease, White race/skin color, and lower serum albumin, HGS, and SMI. The primary tumor site also contributed to changes in SMD in all models, specifically those located in the gastrointestinal tract, gynecologic, and bone and connective tissue. CONCLUSION: In this group of patients with metastatic cancer, lower SMD was associated with older age, White race/skin color, and an overall worse clinical condition.

Skeletal muscle and visceral adipose radiodensities are pre-surgical, non-invasive markers of aggressive kidney cancer.

INTRODUCTION: Most studies on body composition in kidney cancer have been conducted among patients with metastatic disease. Given that aggressive tumours can adversely impact body composition and even non-metastatic tumours can be aggressive, we evaluated associations between pre-surgical body composition features and tumour pathological features in patients with non-metastatic clear cell renal cell cancer (ccRCC). METHODS: The Resolve Cohort consists of 1239 patients with non-metastatic ccRCC who underwent nephrectomy at Memorial Sloan Kettering Cancer Center between 2000 and 2020. The cross-sectional areas and radiodensities of skeletal muscle, visceral adipose, and subcutaneous adipose tissues were determined from pre-surgical computed tomography (CT) scans at the third lumbar vertebrae using Automatica software. Pearson's correlation coefficients describe inter-relationships among BMI and body composition variables, while odds ratios (OR) and 95% confidence intervals (CI) estimate associations between continuous body composition features (per 1-standard deviation) and advanced stage (Stage III vs. Stages I-II) and high Fuhrman grade (Grades 3-4 vs. 1-2) from multivariable logistic regression models that considered the potential impact of biological sex, contrast enhanced CTs, and early age at onset of ccRCC. RESULTS: The cohort was predominantly male (69%), white (89%), and had a median age of 58. The proportion of patients presenting with advanced stage and high-grade disease were 31% and 51%, respectively. In models that adjusted for demographics and all body composition variables simultaneously, decreasing skeletal muscle radiodensity (i.e., more fat infiltration) but increasing visceral adipose tissue radiodensity (i.e., more lipid depletion) were associated with advanced tumour features. Per 8.4 HU decrease in skeletal muscle radiodensity, the odds of presenting with advanced stage was 1.61 (95% CI: 1.34-1.93). Per 7.22 HU increase in visceral adipose tissue radiodensity, the odds of presenting with advanced stage was 1.45 (95% CI: 1.22-1.74). Skeletal muscle index (i.e., sarcopenia) was not associated with either tumour feature. Similar associations were observed for Fuhrman grade, a more direct marker of tumour aggressiveness. Associations did not differ by sex, contrast use, or age at onset of ccRCC. CONCLUSIONS: Lipid infiltrated skeletal muscle, but lipid depleted visceral adipose tissue were independently associated with advanced tumour features in non-metastatic ccRCC. Findings highlight the importance of evaluating the full range of body composition features simultaneously in multivariable models. Interpreting pre-surgical CTs for body composition for patients may be a novel and non-invasive way to identify patients with aggressive renal tumours, which is clinically relevant as renal biopsies are not routinely performed.

Adipose tissue composition determines its computed tomography radiodensity.

OBJECTIVES: Adipose tissue radiodensity in computed tomography (CT) performed before surgeries can predict surgical difficulty. Despite its clinical importance, little is known about what influences radiodensity. This study combines desorption electrospray ionization mass spectrometry imaging (DESI-MSI) and electrospray ionization (ESI) with machine learning to unveil how chemical composition of adipose tissue determines its radiodensity. METHODS: Patients in the study underwent abdominal surgeries. Before surgery, CT radiodensity of fat near operated sites was measured. Fifty-three fat samples were collected and analyzed by DESI-MSI, ESI, and histology, and then sorted by radiodensity, demographic parameters, and adipocyte size. A non-negative matrix factorization (NMF) algorithm was developed to differentiate between high and low radiodensities. RESULTS: No associations between radiodensity and patient age, gender, weight, height, or fat origin were found. Body mass index showed negative correlation with radiodensity. A substantial difference in chemical composition between adipose tissues of high and low radiodensities was observed. More radiodense tissues exhibited greater abundance of high molecular weight species, such as phospholipids of various types, ceramides, cholesterol esters and diglycerides, and about 70% smaller adipocyte size. Less radiodense tissue showed high abundance of short acyl-tail fatty acids. CONCLUSIONS: This study unveils the connection between abdominal adipose tissue radiodensity and its chemical composition. Because the radiodensity of the fat around the surgical site is associated with surgical difficulty, it is important to understand how adipose tissue composition affects this parameter. We conclude that fat tissue with a higher content of various phospholipids and waxy lipids is more CT radiodense. CLINICAL RELEVANCE STATEMENT: This study establishes the connection between the CT radiodensity of adipose tissue and its chemical composition. Clinicians may use this information for preoperative planning of surgical procedures, potentially modifying their surgical approach (for example, performing partial nephrectomy openly rather than laparoscopically). KEY POINTS: • Adipose tissue radiodensity values in computed tomography images taken prior to the surgery can potentially predict surgery difficulty. • Fifty-three human specimens were analyzed by advanced mass spectrometry, molecular imaging, and machine learning to establish the key features that determine Hounsfield units' values of adipose tissue. • The findings of this research will enable clinicians to better prepare for surgical procedures and select operative strategies.

The True-Blue technique: Enhanced chondral assessment of the chest wall.

There is a growing understanding and identification of costal cartilage injuries, however, diagnosis of these injuries remains difficult. We present a novel radiodensity based coloring technique, termed the True-Blue technique, to manipulate 3D CT imaging and more accurately diagnose costochondral injuries.

Correlation of 18F-sodium fluoride uptake and radiodensity in extraosseous metastases of medullary thyroid carcinoma

ABSTRACT Objective: Although 18F-sodium fluoride (18F-NaF) uptake is frequently observed in extraosseous metastases of medullary thyroid carcinoma (MTC) with calcification, it can also occur in metastatic sites without visible calcium deposition, leading to the hypothesis that visually undetectable calcium accumulation may be responsible for this uptake. The aim of this study was to indirectly support this hypothesis by analyzing the correlation between the degree of 18F-NaF uptake and radiodensity in extraosseous MTC metastases, since calcium deposition can increase attenuation even when not visually detectable. Subjects and methods: Extraosseous metastatic lesions of 15 patients with MTC were evaluated using 18F-NaF positron-emission tomography (PET)/computed tomography (CT) and segmented by levels of standardized uptake value (SUV). The correlation between mean SUV and mean Hounsfield unit (HU) values was assessed for the entire group of segments and for two subgroups with different mean HU values. Results: Very high correlations were observed between mean SUV and mean HU values for both the entire group of segments and the subgroup with a mean HU value greater than 130 (p = 0.92 and p = 0.95, respectively; p < 0.01). High correlation (p = 0.71) was also observed in the subgroup with mean HU values ranging from 20 to 130 (p < 0.01). Conclusion: The findings of the present study suggest that there is an association between 18F-NaF uptake and calcium deposition in extraosseous metastases of MTC, supporting the hypothesis that visually undetectable calcium accumulation may be responsible for 18F-NaF uptake in regions without visible calcium deposition.