Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography: A Systematic Review

Computed Tomography Assessment of Sarcopenic Myosteatosis for Predicting Overall Survival in Colorectal Carcinoma: Systematic Review

BACKGROUND

As the US population ages, cancer incidence and prevalence are projected to increase. In the last decade, there has been an increased interest in the opportunistic use of computed tomography (CT) scan data to predict cancer prognosis and inform treatment based on body composition measures, especially muscle measures for sarcopenia.

OBJECTIVE

This article aimed to perform a systematic review of current literature related to CT assessment of muscle attenuation values for myosteatosis in colorectal cancer (CRC) survival prediction.

RESULTS

Initial broad search of CT and CRC yielded 4234 results. A more focused search strategy narrowed this to 129 research papers, and 13 articles met the final inclusion criteria. Twelve of 13 studies found a statistically significant decrease in overall survival according to Hounsfield unit (HU)-based sarcopenia, with hazard ratios ranging from 1.36 to 2.94 (mean, 1.78). However, the specific criteria used to define myosteatosis by CT varied widely, with attenuation thresholds ranging from 22.5 to 47.3 HU, often further subdivided by sex and/or body mass index.

CONCLUSIONS

Current evidence suggests that a strong association between CT-based muscle attenuation values for myosteatosis assessment correlates with overall survival in CRC. However, more research is needed to verify these findings and determine appropriate threshold values for more diverse patient populations. Because CRC patients are staged and followed by CT, the opportunity exists for routine objective myosteatosis assessment in the clinical setting.

Sarcopenia in rheumatic disorders: what the radiologist and rheumatologist should know

Sarcopenia is defined as the loss of muscle mass, strength, and function. Increasing evidence shows that sarcopenia is common in patients with rheumatic disorders. Although sarcopenia can be diagnosed using bioelectrical impedance analysis or DXA, increasingly it is diagnosed using CT, MRI, and ultrasound. In rheumatic patients, CT and MRI allow "opportunistic" measurement of body composition, including surrogate markers of sarcopenia, from studies obtained during routine patient care. Recognition of sarcopenia is important in rheumatic patients because sarcopenia can be associated with disease progression and poor outcomes. This article reviews how opportunistic evaluation of sarcopenia in rheumatic patients can be accomplished and potentially contribute to improved patient care.

Sarcopenia: how to measure, when and why

Sarcopenia indicates a loss of skeletal muscle mass, a condition that leads to a decline in physical performance. In 2018, the European Working Group on Sarcopenia in Older People met to update the original definition of sarcopenia: New scientific and clinical insights were introduced to emphasize the importance of muscle strength loss as a prime indicator of probable sarcopenia. In addition, the skeletal muscle is not only the organ related to mobility, but it is recognized as a secondary secretory organ too, with endocrine functions influencing several systems and preserving health. In this perspective, radiology could have a major role in early detection of sarcopenia and guarantee improvement in its treatment in clinical practice. We present here an update of clinical knowledge about sarcopenia and advantages and limitations of radiological evaluation of sarcopenia focusing on major body composition imaging modalities such as dual-energy X-ray absorptiometry, CT, and MRI. In addition, we discuss controversial such as the lack of consensus or standardization, different measurement methods, and diagnostic radiological cutoff points. Sarcopenia evaluation with radiological methods could enhance the role of radiologist in performing studies with relevant impact on medical and social outcome, placing radiology at the pinnacle of quality in evidence-based practice with high-level studies.

Relation between skeletal muscle volume and prognosis in rectal cancer patients undergoing neoadjuvant therapy

The prognostic role of body composition indexes, and specifically sarcopenia, has recently been explored in different cancer types. However, conflicting results have been reported. Heterogeneity in cancer type, cancer stage or oncological treatments, as well as different methodology and definition of sarcopenia, could be accounted for different conclusions retrieved from literature. When focusing on colorectal cancer, it clearly appears that colon and rectal cancers are often treated as a single entity though they have different behaviors and treatments. Particularly, patients with advanced rectal cancer represent a peculiar group of patients that according to current guidelines are treated with neoadjuvant chemotherapy and radiotherapy followed by radical surgery. This review was restricted to a homogeneous group of patients with advanced lower rectal cancer and the aim of exploring whether there is a correlation between skeletal muscle depletion and prognosis. Literature was searched for articles related to patients with advanced rectal cancer undergoing neoadjuvant chemo-radiotherapy (NCRT) followed by radical surgery, in whom muscle mass and/or change in muscle mass during neoadjuvant treatment were measured. Eight full-text articles were selected and included in the present review. The main findings of our review were: (1) The majority of the studies defined sarcopenia as muscle mass alone over muscle strength or physical performance; (2) There was a great deal of heterogeneity in the definition and measures of sarcopenia, in the definition of cut-off values, and in the method to measure change in muscle mass; (3) There was not full agreement on the association between sarcopenia at baseline and/or after chemo-radiotherapy and prognosis, and only few studies found a significance in the multivariate analysis; and (4) It seems that a loss in skeletal muscle mass during NCRT is associated with the worst outcomes in terms of disease-free survival. In conclusion, analysis of muscle mass might provide prognostic information on patients with rectal cancer, however more robust evidence is needed to define the role of muscle depletion and/or muscle change during neoadjuvant treatments, related to this specific group of patients. If a prognostic role would be confirmed by future studies, the role of preoperative intervention aimed at modifying muscle mass could be explored in order to improve outcomes.

Nutritional status in the pediatric oncology patients

Nutritional status plays a vital role in the growth of children. In pediatric patients, disease-related malnutrition is a dynamic and multifactorial process supported by several factors such as inflammation, increased energy expenditure, decreased intake or reduced utilization of nutrients. In pediatric patients with malignancies, sarcopenia may coexist with malnutrition, amplifying its negative impact on prognosis. Careful monitoring of nutritional status both at diagnosis and during chemotherapy treatment allows early detection of the risk and/or presence of malnutrition. A rapid and personalized nutritional intervention can improve adherence to treatment, reduce complications and improve the patients' quality of life.

Recovery of Muscle Atrophy and Fatty Infiltration in Patients With Acetabular Dysplasia After Total Hip Arthroplasty

INTRODUCTION

Hip osteoarthritis (OA) with acetabular dysplasia negatively affects pelvic alignment and muscle function. We aimed to investigate the changes in muscle atrophy and fatty infiltration of the hip and trunk muscles 1 year after total hip arthroplasty (THA) in patients with hip OA with acetabular dysplasia.

METHODS

This study included 51 female patients who underwent THA for unilateral hip OA with acetabular dysplasia. The cross-sectional area (CSA) and muscle density of the gluteus maximus, gluteus medius, gluteus minimus, piriformis, iliopsoas, rectus abdominis, and abdominal oblique muscles using computer tomography and pelvic inclination angle using radiographs were assessed before and 1 year after THA.

RESULTS

At the 1-year follow-up, the CSA and muscle density of the gluteus medius (2,078 to 2,522 mm2 and 30.3 to 39.4 hounsfield units [HU]), iliopsoas (715 to 901 mm2 and 40.3 to 50.8 HU), and rectus abdominis (336 to 363 mm2 and 28.6 to 30.6 HU) of the affected limb had increased significantly (P < 0.05). The CSA and muscle density of the gluteus maximus (2,429 versus 2,884 mm2 and 23.7 versus 32.6 HU), gluteus minimus (636 versus 785 mm2 and 14.3 versus 37.1 HU), piriformis (505 versus 607 mm2 and 23.4 versus 31.6 HU), and iliopsoas (901 versus 997 mm2 and 50.8 versus 54.5 HU) in the affected limb were lower than those in the unaffected limb (P < 0.01). Postoperatively, the CSA and muscle density of the rectus abdominis were not significantly different between the limbs, and the pelvic inclination angle (35.2° to 32.1°, P < 0.01) was significantly decreased.

DISCUSSION

Compared with the nonoperated limb, substantial atrophy and fatty infiltration of most hip muscles persisted in the operated limb 1 year after THA in patients with acetabular dysplasia; asymmetry in the rectus abdominis muscle fully resolved. In patients with acetabular dysplasia, the surgical technique and postoperative rehabilitation should be further considered to optimize hip muscle recovery.

Myosteatosis as an independent risk factor for mortality after kidney allograft transplantation: a retrospective cohort study

BACKGROUND

Patients with end-stage renal disease may display both a loss of skeletal muscle mass and an increase in muscle fat deposits. We aimed to analyse the impact of low skeletal muscle mass index (SMI, surrogate marker of sarcopenia) and low muscle density (MD, surrogate marker of myosteatosis) on patient survival after kidney transplantation (KT).

METHODS

In a retrospective cohort of 200 kidney transplant recipients (KTr), we measured on an unenhanced cross-sectional computed tomography scan taken at the level of the third lumbar vertebra within the previous year or at the time of KT, both SMI (muscle cross-sectional area normalized for height² , reported in cm² /m² ) and MD (mean attenuation of muscle cross-sectional area, expressed in Hounsfield units). We determined age-specific and sex-specific normality thresholds on 130 healthy subjects. The baseline factors associated with low MD were assessed by logistic regression analysis. Cox proportional hazard univariable and multivariable models were constructed to identify predictive factors of patient survival.

RESULTS

Among the 200 patients of the cohort, 123 were male (62%), and mean age was 54.8 ± 13.8 years. A total of 181 KTr required renal replacement therapy before KT (91%), and 36 KTr (18%) received repeat kidney transplant after previous failed KT. Mean MD was 30.6 ± 9 HU in men and 29.7 ± 8.3 HU in women, whereas SMI was 49.7 ± 8.6 cm² /m² in men and 42.3 ± 7.3 cm² /m² in women. MD was below the 2.5th percentile for the healthy population in 49 KTr (25%), defining the myosteatosis group, while SMI was below the 2.5th percentile for the reference population in 10 KTr (5%). Independent risk factors for myosteatosis were two or more KT [adjusted odds ratio (aOR) 5.2, 95% confidence interval (95% CI): 2.22-12.4, P = 0.0001], a history of stroke (aOR 3.7, 95% CI: 1.30-10.7, P = 0.015), and body mass index > 25 kg/m² (aOR 2.94, 95% CI: 1.4-6.18, P = 0.004). Myosteatosis was independently associated with mortality [adjusted hazard ratio (aHR) 2.12, 95% CI: 1.06-4.24, P = 0.033], as were cardiovascular disease (HR 2.06, 95% CI: 1.02-4.15, P = 0.043) and age (aHR 1.06, 95% CI: 1.03-1.09, P = 0.0003). Low SMI was not associated with mortality.

CONCLUSIONS

Myosteatosis, which was more prevalent than low skeletal muscle mass, might be an important prognostic marker in patients undergoing KT.

A reliable and robust method for the upper thigh muscle quantification on computed tomography: toward a quantitative biomarker for sarcopenia

Background

We aimed to evaluate the feasibility of the upper thigh level as a landmark to measure muscle area for sarcopenia assessment on computed tomography (CT).

Methods

In the 116 healthy subjects who performed CT scans covering from mid-abdomen to feet, the skeletal muscle area in the upper thigh level at the inferior tip of ischial tuberosity (SMA_UT), the mid-thigh level (SMA_MT), and L3 inferior endplate level (SMA_L3) were measured by two independent readers. Pearson correlation coefficients between SMA_UT, SMA_MT, and SMA_L3 were calculated. Inter-reader agreement between the two readers were evaluated using intraclass correlation coefficient (ICC) and Bland-Altman plots with 95% limit of agreement (LOA).

Results

In readers 1 and 2, very high positive correlations were observed between SMA_UT and SMA_MT (r = 0.91 and 0.92, respectively) and between SMA_UT and SMA_L3 (r = 0.90 and 0.91, respectively), while high positive correlation were observed between SMA_MT and SMA_L3 (r = 0.87 and 0.87, respectively). Based on ICC values, the inter-reader agreement was the best in the SMA_UT (0.999), followed by the SMA_L3 (0.990) and SMA_MT (0.956). The 95% LOAs in the Bland-Altman plots indicated that the inter-reader agreement of the SMA_UT (− 0.462 to 1.513) was the best, followed by the SMA_L3 (− 9.949 to 7.636) and SMA_MT (− 12.105 to 14.605).

Conclusion

Muscle area measurement at the upper thigh level correlates well with those with the mid-thigh and L3 inferior endpoint level and shows the highest inter-reader agreement. Thus, the upper thigh level might be an excellent landmark enabling SMA_UT as a reliable and robust biomarker for muscle area measurement for sarcopenia assessment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05032-2.

Clinical Impact of Nutritional Status and Sarcopenia in Pediatric Patients with Bone and Soft Tissue Sarcomas: A Pilot Retrospective Study (SarcoPed)

BACKGROUND

We evaluated nutritional and sarcopenia status and their clinical impact in pediatric patients affected by bone and soft tissue sarcomas.

METHODS

Body mass index (BMI), prognostic nutritional index (PNI), and total psoas muscle area (tPMA) at diagnosis and after 12 months were analyzed. tPMA was measured from single cross-sectional computed tomography (CT) images at L4-L5. Age-specific and sex-specific tPMA Z-scores were retrieved from an online calculator.

RESULTS

A total of 21 patients were identified between February 2013 and December 2018. Twelve patients (57.1%) experienced sarcopenia at diagnosis, although not statistically associated with overall survival (OS) (p = 0.09). BMI Z-score, PNI, and tPMA Z-score significantly decreased between diagnosis and after 12 months of treatment (p < 0.05). Univariate analysis showed significant associations between poor OS and the presence of metastasis (p = 0.008), the absence of surgery (p = 0.005), PNI decrease (p = 0.027), and the reduction in tPMA > 25% (p = 0.042) over the 12 months.

CONCLUSIONS

Sarcopenia affects more than half of the patients at diagnosis. Decreased PNI during 12 months of treatment has significant predictive value for OS. The role of tPMA derived from CT scan among pediatric patients with sarcoma should be investigated in further prospective and larger studies.

Sarcopenia, Precardial Adipose Tissue and High Tumor Volume as Outcome Predictors in Surgically Treated Pleural Mesothelioma

BACKGROUND

We evaluated the prognostic value of Sarcopenia, low precardial adipose-tissue (PAT), and high tumor-volume in the outcome of surgically-treated pleural mesothelioma (PM).

METHODS

From 2005 to 2020, consecutive surgically-treated PM-patients having a pre-operative computed tomography (CT) scan were retrospectively included. Sarcopenia was assessed by CT-based parameters measured at the level of the fifth thoracic vertebra (TH5) by excluding fatty-infiltration based on CT-attenuation. The findings were stratified for gender, and a threshold of the 33rd percentile was set to define sarcopenia. Additionally, tumor volume as well as PAT were measured. The findings were correlated with progression-free survival and long-term mortality.

RESULTS

Two-hundred-seventy-eight PM-patients (252 male; 70.2 ± 9 years) were included. The mean progression-free survival was 18.6 ± 12.2 months, and the mean survival time was 23.3 ± 24 months. Progression was associated with chronic obstructive pulmonary disease (COPD) (p = <0.001), tumor-stage (p = 0.001), and type of surgery (p = 0.026). Three-year mortality was associated with higher patient age (p = 0.005), presence of COPD (p < 0.001), higher tumor-stage (p = 0.015), and higher tumor-volume (p < 0.001). Kaplan-Meier statistics showed that sarcopenic patients have a higher three-year mortality (p = 0.002). While there was a negative correlation of progression-free survival and mortality with tumor volume (r = 0.281, p = 0.001 and r = -0.240, p < 0.001; respectively), a correlation with PAT could only be shown for epithelioid PM (p = 0.040).

CONCLUSIONS

Sarcopenia as well as tumor volume are associated with long-term mortality in surgically treated PM-patients. Further, while there was a negative correlation of progression-free survival and mortality with tumor volume, a correlation with PAT could only be shown for epithelioid PM.

Quantitative assessment of muscle mass and gene expression analysis in dogs with glucocorticoid-induced muscle atrophy

The present study aimed to quantitatively evaluate muscle mass and gene expression in dogs with glucocorticoid-induced muscle atrophy. Five healthy beagles received oral prednisolone for 4 weeks (1 mg/kg/day), and muscle mass was then evaluated via computed tomography. Histological and gene expression analyses were performed using biopsy samples from the biceps femoris before and after prednisolone administration. The cross-sectional area of the third lumbar paraspinal and mid-femoral muscles significantly decreased after glucocorticoid administration (from 27.5 ± 1.9 to 22.6 ± 2.0 cm² and from 55.1 ± 4.7 to 50.7 ± 4.1 cm², respectively; P<0.01). The fast- and slow-twitch muscle fibers were both atrophied (from 2,779 ± 369 to 1,581 ± 207 μm² and from 2,871 ± 211 to 1,971 ± 169 μm², respectively; P<0.05). The expression of the growth factor receptor-bound protein 10 (GRB10) significantly increased after prednisolone administration (P<0.05). Because GRB10 suppresses insulin signaling and the subsequent mammalian target of rapamycin complex 1 activity, increased expression of GRB10 may have resulted in a decrease in protein anabolism. Taken together, 1 mg/kg/day oral prednisolone for 4 weeks induced significant muscle atrophy in dogs, and GRB10 might participate in the pathology of glucocorticoid-induced muscle atrophy in canines.

Sarcopenia: imaging assessment and clinical application

Sarcopenia is a progressive, generalized skeletal muscle disorder characterized by reduction of muscle mass and strength. It is associated with increased adverse outcomes including falls, fractures, physical disability, and mortality, particularly, in elderly patients. Nowadays, sarcopenia has become a specific imaging biomarker able to predict clinical outcomes of patients. Muscle fibre reduction has shown to be an unfavourable pre-operative predictive factor in patients with cancer, and is associated with worse clinical outcomes in terms of postoperative complications, morbidity, mortality, and lower tolerance of chemoradiation therapy. Several imaging modalities, including dual-energy X-ray absorptiometry, CT, MRI, and US can be used to estimate muscle mass and quality to reach the diagnosis of sarcopenia. This article reviews the clinical implications of sarcopenia, how this condition can be assessed through different imaging modalities, and future perspectives of imaging of sarcopenia.

Accelerated loss of trunk muscle density and size at L1 vertebral level in male patients with COPD

BACKGROUND AND PURPOSE

Weight loss and muscle mass loss are common in patients with chronic obstructive pulmonary disease (COPD). Muscle density and fat infiltration based on CT images may be more sensitive than muscle mass by DXA in the assessment of sarcopenia for COPD patients. However, the age-related changes of cross-sectional trunk muscle compositions based on lung CT scans are still unknown. Thus, we aimed to investigate over time the change in muscle density, size, and fat deposition of L1-level trunk muscles in patients with COPD.

MATERIALS AND METHODS

129 male COPD patients with a second chest CT scan (from 2013-2019 to 2014-2020) were enrolled. The CT images at first and second CT scans are analyzed by OsiriX software. Trunk muscles at the level of the 1st lumbar vertebrae were selected for analysis. Attenuation of lumbar vertebrae 1 was also measured from chest CT images. The pulmonary function values were calculated based on forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC).

RESULTS

The mean age of the 129 patients with COPD was 69.7 years. The durations of COPD of this cohort were from 8-17 years. The mean area and density of L1 trunk muscles were 85.5 cm² and 36.4 HU. At baseline, muscle area and density and vertebral density were negatively associated with age (p<0.0001), while the intermuscular fat area and the fat infiltration ratio were not significantly associated with age (p>0.05). The per-year loss of trunk muscle area was 2.83 cm² (p<0.0001) which accounts for 3.3% decrease per year, and the per-year decrease of trunk muscle density was 2.41 HU (p<0.0001) which accounts for 6.6% decrease per year. The per-year increase of intermuscular fat in trunk muscles was 0.57 cm² (p=0.006) which accounts for 11.1% increase per year. The bone density loss was 5.63 HU/per year (p<0.0001).

CONCLUSION

Men with COPD had accelerated muscle loss as well as increased fat infiltration. Compared to muscle quantity loss, the decline in muscle quality is much larger, indicating the importance of relevant interventions focusing on improving muscle quality.

Correlation Between Bioelectrical Impedance Analysis and Chest CT-Measured Erector Spinae Muscle Area: A Cross-Sectional Study

BACKGROUND

Skeletal muscle mass (SMM) plays an important part in diverse health and disease states. Bioelectrical impedance analysis (BIA) and computed tomography (CT) are available for its assessment. However, muscle mass assessed by BIA may be influenced by multiple factors. The erector spinae muscle area (ESA) on chest CT is recently presumed to be representative of SMM. This study aimed to derive BIA from the ESA and evaluate the magnitude of association (between ESA measured from chest CT) and BIA.

METHODS

Subjects hospitalized for health checkups between December 2020 and December 2021, having undergone both BIA (50 kHz, 0.8 mA) and chest CT, were included. ESA was quantified at the level of the 12th thoracic vertebra (T12-ESA) by a standardized semi-automated segmentation algorithm. Low SMM was defined using the Asian Working Group for Sarcopenia criteria. The association between T12-ESA and BIA was then evaluated. Stratified analyses by sex and BMI were also performed.

RESULTS

Among 606 included subjects (59.7 ± 16.6 years, 63.5% male), 110 (18.2%) had low SMM. BMI in low and normal SMM groups was 20.1 and 24.7 kg/m², respectively. Current smoking, drinking, chronic obstructive pulmonary disease, and chronic renal dysfunction were more frequently seen in the low SMM group than in the normal SMM group. The final regression model included T12-ESA, weight, BMI, and age, and had an adjusted R² of 0.806 with BIA. In the validation group, the correlation between T12-ESA-derived BIA and BIA remained high (Pearson correlation = 0.899). Stratified analysis disclosed a stronger correlation between T12-ESA and BIA in male subjects than in female subjects (adjusted R² = 0.790 vs. adjusted R² = 0.711, p < 0.05), and a better correlation was observed in obese (BMI ≥ 30 kg/m²) compared with underweight (BMI < 18.5 kg/m²) subjects (adjusted R^{2 =} 0.852 vs. adjusted R² = 0.723, p < 0.05). Additional analysis revealed a significant correlation between T12-ESA and skeletal muscle cross-sectional area at the 3rd lumbar vertebra (L3-CSA) (adjusted R² = 0.935, p < 0.001).

CONCLUSIONS

CT-based assessment of ESA at the T12 level is feasible and correlated well with BIA, especially in male subjects and obese subjects.

Malnutrition in Relation to Muscle Mass, Muscle Quality, and Muscle Strength in Hospitalized Older Adults

OBJECTIVES

Muscle quality is an essential muscle metric, which can be assessed by measuring intermuscular adipose tissue (IMAT) and skeletal muscle radiodensity (SMD) via computed tomography (CT) images. We aimed to explore the associations of Global Leadership Initiative on Malnutrition (GLIM)-defined malnutrition with muscle mass, muscle quality, and muscle strength in hospitalized older adults.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

Hospitalized older patients.

METHODS

Malnutrition was defined by the GLIM criteria after screening by the Mini Nutrition Assessment-Short Form (MNA-SF). Chest CT images were used to segment skeletal muscle area (SMA) and IMAT, and to measure SMD. Skeletal muscle index (SMI) was calculated by SMA (cm²)/body height squared (m²). Handgrip strength (HGS) was measured using a digital dynameter. Univariate and multivariate logistic regression models were performed to calculate odds ratios (ORs) and 95% CIs.

RESULTS

We included 1135 patients. The MNA-SF score is positively associated with SMI, SMD, and HGS, but negatively associated with IMAT. Compared to patients with normal nutrition, patients with malnutrition had significantly lower SMD and HGS in both men and women. Women with malnutrition had significantly higher IMAT than women with normal nutrition, whereas men with malnutrition had significantly lower SMI than men with normal nutrition. After adjustment for confounders, SMI (adjusted OR 0.95, 95% CI 0.93, 0.98), SMD (adjusted OR 0.94, 95% CI 0.93, 0.98), and HGS (adjusted OR 0.91, 95% CI 0.89, 0.94) were significantly and negatively associated with malnutrition. IMAT appeared to be positively associated with malnutrition, but the result was not statistically significant (adjusted OR 1.03, 95% CI 1.00, 1.07).

CONCLUSIONS AND IMPLICATIONS

Our study provides new evidence regarding the association between handgrip strength and malnutrition in older inpatients. Moreover, a small association of chest CT--derived muscle quality and mass with malnutrition is identified.

Skeletal muscle depletion predicts death in severe community-acquired pneumonia patients entering ICU

BACKGROUND

Sarcopenia, or skeletal muscle depletion, was common in the elderly and often led to a poor prognosis of diseases. The area of the psoas muscle in abdominal computed tomography (CT) is the most common used for diagnosing sarcopenia. However, patients with pneumonia routinely only undergo chest CT.

OBJECTIVES

This study aimed to determine whether paraspinal muscle area (PMA) obtained by chest CT can predict death for community-acquired pneumonia (SCAP) patients entering intensive care unit (ICU).

METHODS

This study enrolled 208 SCAP patients admitted to ICU after undergoing chest CT. PMA, paraspinal muscle radiodensity (PMD), and lean paraspinal muscle area (LPMA) were calculated on chest CT images. The main outcome was mortality during hospitalization. Logistic regression, receiver operating characteristic (ROC) curve, and Kaplan-Meier curves were used to evaluate forecasting effectiveness.

RESULTS

The primary outcome occurred in 76 (36.53%) patients. In multivariate logistic regression, PMA, lactic dehydrogenase (LDH), invasive mechanical ventilation (IMV), red blood cell (RBC) and age≥ 65 years were independent risk factors predicting death during hospitalization (adjusted Odds Ratio [OR]: 0.886, 1.002, 3.178, 0.612 and 2.003, respectively). The area under curve (AUC) of PMA to predict death was 0.720 (P< 0.001). During hospitalization, the median survival time of high-PMA (51.00 days) and low-PMA groups (20.00 days) was statistically significant (P< 0.001).

CONCLUSION

Lower PMA was associated with an increased risk of death for SCAP patients admitted to the ICU. In other words, PMA may help early identify adverse prognosis of SCAP patients admitted to ICU.

Subcutaneous fat area at the upper thigh level is a useful prognostic marker in the elderly with femur fracture

BACKGROUND

The aim of this study was to evaluate prognostic value of body tissue composition at the upper thigh level for 1 year mortality in elderly patients with proximal femur fracture.

METHODS

This retrospective cohort study included consecutive elderly (aged ≥65) patients diagnosed with proximal femur fracture based on the findings of pelvic bone computed tomography (CT) performed at the emergency department of a tertiary care hospital and treated with surgery between 2010 and 2017. The cross-sectional area of subcutaneous fat and skeletal muscle at the upper thigh level was measured using CT. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for 1 year mortality were estimated using a Cox proportional hazards model. Survival based on the SFA quartiles was assessed using nonparametric Kaplan-Meier survival analysis and compared used log-rank tests.

RESULTS

Among 876 elderly patients included in this study, the median age was 79.0 years, and 646 (73.7%) patients were female. A total of 93 (10.6%) died within 1 year after admission to the emergency department. Survivors had a significantly higher median subcutaneous fat area (SFA) than non-survivors (170.2 vs. 133.0 cm² , P < 0.001), but no significant difference was observed between the skeletal muscle area (median, 156.7 vs. 160.3 cm² , P = 0.504) and muscle density (median, 19.0 vs. 19.1 HU, P = 0.861) of both groups. After adjustment of other clinical characteristics and body compositions, the multivariate Cox proportional hazard analysis showed that SFA (adjusted HR, 0.987; 95% CI, 0.982-0.992; P < 0.001) was independently associated with 1 year mortality. With 384 deaths during 51 322 person-months of follow-up, the median estimated survival duration of all the patients was 92.8 months (95% CI, 80.8-104.7 months). The patients with SFA in the third (165.6-195.0 cm² ) and fourth (>195.0 cm² ) quartiles showed significantly longer survival duration than those with SFA in the first (<131.4 cm² ; median survival time, 51.3 months) and second (131.4-165.5 cm² ; median survival time, 88.7 months) quartiles (P < 0.001 by log-rank test).

CONCLUSIONS

The SFAs measured at the upper thigh level and 1 year mortality are positively associated in elderly patients with proximal femur fracture. SFA may be an independent prognostic biomarker for 1 year mortality of femur fracture.

Preoperative Muscle Strength Is a Predictor of Outcomes After Esophagectomy

BACKGROUND

Sarcopenia, loss of muscle mass and strength, has been associated with more frequent complications after esophagectomy. This study compared hand-grip strength, muscle mass, and intramuscular adipose tissue as predictors of postoperative outcomes and mortality after esophagectomy.

METHODS

Minimally invasive esophagectomy was performed on 175 patients with esophageal cancer. Skeletal muscle index and skeletal muscle density were derived from preoperative CTs. Hand-grip strength was measured using dynamometer. Univariate and multivariable analyses were performed.

RESULTS

Preoperative hand-grip strength was normal in 91 (52%), intermediate in 43 (25%), and weak in 41 (23%) patients. Hand-grip strength was significantly correlated with both skeletal muscle index and skeletal muscle density. Postoperative pneumonia occurred in 8/41 (20%) patients with weak strength compared to 4/91 (4%) with normal strength (p = 0.006; Cochran-Armitage Test). Prolonged postoperative ventilation occurred in 11/41 (27%) patients with weak strength compared to 11/91 (12%) with normal strength (p = 0.036). Median length of stay was 9 days in patients with weak strength compared to 7 days for those with normal strength (p = 0.005; Kruskal-Wallis Test). Discharge to non-home location occurred in 15/41 (37%) with weak strength compared to 8/91 (9%) with normal strength (p < 0.001). Postoperative mortality at 90 days was 4/41 (10%) with weak strength compared with no mortalities (0/91) in the normal strength group (p = 0.004). Mortality at 1 year was 18/39 (46%) in patients with weak strength compared to 6/81 (7%) with normal strength, among 158 patients with 1-year follow-up (p < 0.001).

CONCLUSIONS

Preoperative hand-grip strength was found to be a powerful predictor of postoperative pneumonia, length of stay, discharge to non-home location, and mortality after esophagectomy.

Reliability and Validity of Abdominal Skeletal Muscle Area Measurement Using Magnetic Resonance Imaging

RATIONALE AND OBJECTIVES

Skeletal muscle mass measurement is the most important element for diagnosing sarcopenia. MRI has an excellent soft-tissue contrast, which can non-invasively assess abdominal skeletal muscle area (SMA) as well as CT. This study aimed to assess the validity and reliability of abdominal SMA measurement by comparing CT and MRI based on the fat image of IDEAL-IQ sequence at the lumbar level mid-L3.

MATERIALS AND METHODS

CT and MRI images of 32 patients diagnosed with various kidney diseases were used to analyze intra-observer variability among abdominal SMA measurements. This was done to evaluate the correlation of SMA between CT and fat images of MRI. SMA images were segmented using Materialise Mimics software before quantification. Interobserver reliability and validation of measurements was evaluated by two independent investigators. Abdominal SMA reproducibility and correlation between CT and MRI were then assessed using the intraclass correlation coefficient (ICC), coefficient of variation (CV), Bland-Altman plot, and Pearson's correlation coefficient respectively.

RESULTS

The interobserver reliability of MRI was excellent. The CV value was 2.82% while the ICC values ranged between 0.996 and 0.999. Validity was high (CV was 1.7% and ICC ranged between 0.986 and 0.996) for measurements by MRI and CT. Bland Altman analysis revealed an average difference of 2.2% between MRI and CT. The Pearson's correlation coefficient was 0.995 (p < 0.0001). This result revealed that there was a strong correlation between the two technologies.

CONCLUSION

MRI exhibited good interobserver reliability and excellent agreement with CT for quantification of abdominal SMA.

Computed tomography-defined low skeletal muscle index and density in cancer patients: observations from a systematic review

BACKGROUND

Computed tomography (CT) analysis of body composition has garnered interest as a potential prognostic tool in those with cancer. A range of pre-defined thresholds currently exist within the literature to define low skeletal muscle mass and density. The aim of the present systematic review was to assess the prevalence of low skeletal muscle index (SMI) and density (SMD) within the literature, across a range of common solid tumours.

METHODS

A systematic search of PubMed was carried out to identify studies reporting CT analysis of SMI and SMD in patients with colorectal, oesophageal, gastric, hepatobiliary, pancreatic, breast, and lung cancer. The type of cancer, whether curative or non-curative disease, the anthropomorphic parameter studied, threshold used to define low SMI and SMD, and the prevalence of these anthropomorphic measurements within the population were recorded.

RESULTS

Of the 160 studies included, 156 reported an assessment of SMI and 35 reported assessment of SMD. The median prevalence of low SMI was 43% (30.1-57.1) and low SMD 49.4% (31.7-58.5) across the entire cohort. There was little variation in the prevalence of low SMI and SMD when studies were divided into curative and non-curative cohorts-40.7% (27.5-51.3) vs. 48.4% (30.9-60.1) and 37.8% (32.2-52.2) vs. 55.3% (38.5-64.7) respectively. When divided into colorectal, oesophageal, gastric, hepatobiliary, pancreatic, breast and lung cancers, similar prevalence of low SMI (46.0% %, 49.8%, 35.7%, 41.1%, 32.3%, 34%, and 49.5%) and low SMD were also observed (52.1%, 54.3%, 71.2%, 56.8%, 55.3%, and 52.6%). This was maintained when studies were stratified into cohorts by threshold used-low SMI (Martin 48.9%, Prado 49.9%, and Others 36.0%) and low SMD (Martin 52.4% and Others 48.6%).

CONCLUSIONS

Low SMI and SMD are endemic across a range of cancer types and disease stage, challenging pre-existing dogma of the determinants of prevalence.

Quality Matters as Much as Quantity of Skeletal Muscle: Clinical Implications of Myosteatosis in Cardiometabolic Health

Although age-related changes in skeletal muscles are closely associated with decreases in muscle strength and functional decline, their associations with cardiometabolic diseases in the literature are inconsistent. Such inconsistency could be explained by the fact that muscle quality-which is closely associated with fatty infiltration of the muscle (i.e., myosteatosis)-is as important as muscle quantity in cardiometabolic health. However, muscle quality has been less explored compared with muscle mass. Moreover, the standard definition of myosteatosis and its assessment methods have not been established yet. Recently, some techniques using single axial computed tomography (CT) images have been introduced and utilized in many studies, as the mass and quality of abdominal muscles could be measured opportunistically on abdominal CT scans obtained during routine clinical care. Yet, the mechanisms by which myosteatosis affect metabolic and cardiovascular health remain largely unknown. In this review, we explore the recent advances in the assessment of myosteatosis and its changes associated with aging. We also review the recent literature on the clinical implication of myosteatosis by focusing on metabolic and cardiovascular diseases. Finally, we discuss the challenges and unanswered questions that need addressing to set myosteatosis as a therapeutic target for the prevention or treatment of cardiometabolic diseases.

Methodology, clinical applications, and future directions of body composition analysis using computed tomography (CT) images: A review

PURPOSE OF THE REVIEW

We aim to review the methods, current research evidence, and future directions in body composition analysis (BCA) with CT imaging.

RECENT FINDINGS

CT images can be used to evaluate muscle tissue, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) compartments. Manual and semiautomatic segmentation methods are still the gold standards. The segmentation of skeletal muscle tissue and VAT and SAT compartments is most often performed at the level of the 3rd lumbar vertebra. A decreased amount of CT-determined skeletal muscle mass is a marker of impaired survival in many patient populations, including patients with most types of cancer, some surgical patients, and those admitted to the intensive care unit (ICU). Patients with increased VAT are more susceptible to impaired survival / worse outcomes; however, those patients who are critically ill or admitted to the ICU or who will undergo surgery appear to be exceptions. The independent significance of SAT is less well established. Recently, the roles of the CT-determined decrease of muscle mass and increased VAT area and epicardial adipose tissue (EAT) volume have been shown to predict a more debilitating course of illness in patients suffering from severe acute respiratory syndrome coronavirus 2 (COVID-19) infection.

SUMMARY

The field of CT-based body composition analysis is rapidly evolving and shows great potential for clinical implementation.

Associations of ADL Disability With Trunk Muscle Mass and Muscle Quality Indicators Measured by Opportunistic Chest Computed Tomography Imaging Among Older Inpatients

Objectives: Sarcopenia is an important predictor of dependence in activities of daily living (ADL disability); however, the association between muscle quality and ADL disability has not been established. We aimed (1) to assess the feasibility of measuring trunk muscle mass and muscle quality by chest CT images; and (2) to explore the possible associations of ADL disability with these muscle mass and muscle quality indicators among older inpatients. Methods: We included older patients in an acute care ward. ADL disability was defined as the Barthel Index (BI) score ≤ 60 points. Unenhanced chest CT images at the 12^th thorax (T12) vertebral level were used to segment skeletal muscle area (SMA) and intermuscular adipose tissue (IMAT) and to measure the mean skeletal muscle radiodensity (SMD). Skeletal muscle index (SMI), the muscle mass indicator, was calculated by SMA (cm²)/body height squared (m²). The percentage of IMAT (IMAT%) was calculated using the equation: IMAT% = IMAT/(SMA+ IMAT) ×100%. Skeletal muscle radiodensity, IMAT, and IMAT% were the muscle quality indicators. Kendall's tau rank correlation coefficients (τ) were calculated to explore the correlations. Univariate and multivariate logistic regression models were performed to calculate odds ratios (OR) and 95% confidence interval (CI). Results: We included 212 participants. Skeletal muscle index and SMD were positively and significantly associated with the BI score (τ = 0.14 and 0.31, respectively, both P < 0.001); whereas IMAT and IMAT% were negatively and significantly associated with the BI score (τ = -0.21, P < 0.001; τ = -0.21, P < 0.012). After adjusting for confounders, SMI (adjusted OR 1.03, 95% CI 0.97-1.09) was not independently associated with ADL disability; however, SMD (adjusted OR 0.94, 95% CI 0.88-0.99), IMAT (adjusted OR 1.11, 95% CI 1.03-1.20), and IMAT% (adjusted OR 1.09, 95% CI 1.02-1.16) were independently associated with ADL disability. Subgroup analysis found similar results in men; however, none of these indicators were independently associated with ADL disability in women. Conclusion: Trunk muscle quality indicators (SMD, IMAT, and IMAT%) measured by chest CT images, but not SMI, are independently associated with ADL disability in a single-center study population of older inpatients, especially in men. Further research is necessary to validate our findings.

Diagnosing sarcopenia and myosteatosis based on chest computed tomography images in healthy Chinese adults

BACKGROUND

Measuring muscle mass and muscle quality based on chest Computed Tomography (CT) images would facilitate sarcopenia and myosteatosis research. We aimed (1) to measure muscle mass and myosteatosis based on chest CT images at the 12th thoracic vertebra level and compare the relevant indicators with whole-body skeletal muscle mass (BSM) and whole-body fat mass (BFM) measured by bioelectrical impedance analysis; and (2) to determine the cut-off points of these indicators for diagnosing sarcopenia or myosteatosis in healthy Chinese adults.

METHODS

Chest CT images were analyzed using a segmentation software. Skeletal muscle area (SMA), skeletal muscle radiodensity (SMD), and intermuscular adiposity tissue (IMAT) were measured. Skeletal muscle indices (SMIs) and IMAT/SMA ratio were calculated.

RESULTS

We included 569 participants. SMA, SMA/height2, and SMA/BMI were strongly and positively correlated with BSM (r = 0.90, 0.72, and 0.69, respectively, all p < 0.001); whereas SMA/weight was moderately and positively correlated with BSM (r = 0.38, p < 0.001). IMAT and IMAT/SMA were strongly and positively correlated with BFM (r = 0.67 and 0.58, respectively, both p < 0.001). SMD was moderately and negatively correlated with BFM (r = - 0.40, p < 0.001). We suggest SMA/height2 (< 25.75 cm2/m2 in men and < 20.16 cm2/m2 in women) for diagnosing sarcopenia and SMD (< 37.42 HU in men and < 33.17 HU in women) or IMAT (> 8.72 cm2 in men and > 4.58 cm2 in women) for diagnosing myosteatosis.

CONCLUSIONS

Muscle mass indicators (SMA and SMIs) and muscle quality indicators (SMD, IMAT, and IMAT/SMA) measured by chest CT images are valuable for diagnosing sarcopenia and myosteatosis, respectively.

Psoriasis Is Associated With Myosteatosis but Not Sarcopenia: A Case-Control Study

Background: The link between psoriasis and body fat (or obesity) has been well established. However, there are no reports detailing the possible relationship between psoriasis and fat infiltration in skeletal muscle, also known as myosteatosis. A recent study reported the possible association between psoriasis, arthritis, and sarcopenia (the loss of skeletal muscle mass or function). The present study aimed to explore the possible associations of chronic plaque psoriasis with myosteatosis and sarcopenia.

Methods: We conducted a case-control study. In-patients with chronic plaque psoriasis were retrospectively recruited. Healthy controls were prospectively and continuously recruited. Unenhanced cross-sectional chest computed tomography images at the 12th thoracic vertebral level were analyzed using Mimics software. Skeletal muscle area (SMA), skeletal muscle radiodensity (SMD), and intermuscular adiposity tissue (IMAT) were measured. The skeletal muscle index (SMI) was calculated as SMA/height². The percentage of IMAT (IMAT%) was calculated as IMAT/SMA × 100%. Myosteatosis was defined by SMD or IMAT%, whereas sarcopenia was defined by SMI. Propensity score matching was performed to adjust for the main confounders. Logistic regression models were used to evaluate the associations of psoriasis with myosteatosis and sarcopenia.

Results: We included 155 psoriasis patients and 512 healthy controls. After propensity score matching, we retained 310 controls. The prevalence of sarcopenia was not significantly different between the psoriasis and control groups (men: 9.8% vs. 14.4%, p = 0.244; women: 7.0% vs. 11.7%, p = 0.548). Psoriasis patients were more prone to SMD-defined myosteatosis (men: 39.3% vs. 20.8%; women: 46.5% vs. 16.0%; both p < 0.001) and IMAT%-defined myosteatosis (men: 21.4% vs. 12.5%, p = 0.034; women: 46.5 vs. 28.7%, p = 0.042) than the control group. After adjustment for potential confounders, psoriasis was not significantly associated with sarcopenia (odds ratio [OR] 0.51, 95% confidence interval [CI] 0.25–1.19, p = 0.136). However, psoriasis was associated with SMD-defined myosteatosis (OR 3.16, 95% CI 1.86–5.37, p < 0.001) and IMAT%-defined myosteatosis (OR 1.76, 95% CI 1.04–3.00; p = 0.037).

Conclusions: Chronic plaque psoriasis is independently associated with myosteatosis but not sarcopenia. Since fat and muscle are considered endocrine organs and can drive the inflammatory process, further studies detailing the interaction between psoriasis, fat, and skeletal muscle are warranted.

Effects of Contrast Phases on Automated Measurements of Muscle Quantity and Quality Using CT

OBJECTIVE

Muscle quantity and quality can be measured with an automated system on CT. However, the effects of contrast phases on the muscle measurements have not been established, which we aimed to investigate in this study.

MATERIALS AND METHODS

Muscle quantity was measured according to the skeletal muscle area (SMA) measured by a convolutional neural network-based automated system at the L3 level in 89 subjects undergoing multiphasic abdominal CT comprising unenhanced phase, arterial phase, portal venous phase (PVP), or delayed phase imaging. Muscle quality was analyzed using the mean muscle density and the muscle quality map, which comprises normal and low-attenuation muscle areas (NAMA and LAMA, respectively) based on the muscle attenuation threshold. The SMA, mean muscle density, NAMA, and LAMA were compared between PVP and other phases using paired t tests. Bland-Altman analysis was used to evaluate the inter-phase variability between PVP and other phases. Based on the cutoffs for low muscle quantity and quality, the counts of individuals who scored lower than the cutoff values were compared between PVP and other phases.

RESULTS

All indices showed significant differences between PVP and other phases (p < 0.001 for all). The SMA, mean muscle density, and NAMA increased during the later phases, whereas LAMA decreased during the later phases. Bland-Altman analysis showed that the mean differences between PVP and other phases ranged -2.1 to 0.3 cm² for SMA, -12.0 to 2.6 cm² for NAMA, and -2.2 to 9.9 cm² for LAMA.The number of patients who were categorized as low muscle quantity did not significant differ between PVP and other phases (p ≥ 0.5), whereas the number of patients with low muscle quality significantly differed (p ≤ 0.002).

CONCLUSION

SMA was less affected by the contrast phases. However, the muscle quality measurements changed with the contrast phases to greater extents and would require a standardization of the contrast phase for reliable measurement.

Functional characteristics associated with hip abductor torque in severe hip osteoarthritis

BACKGROUND

Hip abductor weakness due to the progression of hip osteoarthritis (OA) commonly causes poor functional mobility. The hip abductor strength has also been identified as a clinically relevant factor for successful functional outcomes after total hip arthroplasty.

OBJECTIVES

This study aimed to examine the functional characteristics related to hip abductor torque in patients with hip OA.

DESIGN

A cross-sectional survey study.

METHODS

One hundred and eight female patients with severe unilateral hip OA participated in this study. Hip abductor torque and pain were measured. The muscle cross-sectional area (CSA) and skeletal muscle density (SMD) of the gluteal muscles were also measured using computed tomography. To identify the hip parameters associated with hip abductor torque, multiple regression analysis was performed. The healthy model included the CSA and SMD of gluteus maximus, gluteus medius, and gluteus minimus; range of motion in hip abduction; age; and body mass index. The affected model included hip pain in addition to the healthy model.

RESULTS

In the affected limb, multiple regression analysis identified pain and angle of hip abduction as factors that determine hip abductor torque (Adjusted R² = 0.39). In contrast, our analysis identified CSA and SMD of the gluteus medius and SMD of the gluteus minimus as the significant variables related to hip abductor torque in the healthy limb (Adjusted R² = 0.40).

CONCLUSION

The findings of this study indicated that it is necessary to consider that hip pain may inhibit muscle exertion and contraction while training to improve the hip abductor torque in the affected limb.

Factors That Improve Chest Computed Tomography-Defined Sarcopenia Prognosis in Advanced Non-Small Cell Lung Cancer

BACKGROUND

Whether muscle strength and physical performance should be components of sarcopenia remains controversial. This study evaluated the skeletal muscle index derived from computed tomography images at the 12th thoracic vertebra level (T12 SMI), handgrip strength, performance status, and their combination for predicting overall survival in patients with advanced non-small cell lung cancer.

METHODS

Chest computed tomography, handgrip strength measurement, and bioelectrical impedance analysis were performed. Sarcopenia was defined based on the T12 SMI alone or the T12 SMI, handgrip, and/or physical performance (i.e. Asian Working Group for Sarcopenia [AWGS]-defined sarcopenia or severe sarcopenia).

RESULTS

Overall, 639 participants were included; 488 (76.4%) died. At baseline, 160 (25.0%), 141 (22.1%), and 42 (6.6%) patients had computed tomography-defined sarcopenia, AWGS-defined sarcopenia, and AWGS-defined severe sarcopenia, respectively. Chest computed tomography-defined sarcopenia (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.65-2.43), AWGS-defined sarcopenia (HR, 2.00; 95% CI, 1.59-2.49), and AWGS-defined severe sarcopenia (HR, 3.01; 95% CI, 2.21-4.09) were more strongly associated with poor prognosis than a performance status score ≥2 (HR, 1.37; 95% CI, 1.10-1.73).

CONCLUSIONS

Adding handgrip strength and the performance status score to chest computed tomography-defined sarcopenia improved its prognostic ability. Oncological sarcopenia research should focus on muscle mass, strength, and function.

Myosteatosis reduces overall survival in patients with digestive system malignancies: a meta-analysis with trial sequential analysis

The impact of myosteatosis on the outcomes of digestive malignancies has gained great attention recently. However, studies on the impact of myosteatosis show inconsistent results. We conducted a meta-analysis to clarify the relationship between myosteatosis and the overall survival of digestive cancer patients. The systematic literature search was conducted on PubMed/MEDLINE, Web of Science, and Embase from inception through March 27, 2021. Meta-analysis was performed using the random-effects model. Out of 3451 studies screened, 47 studies including 21,194 patients passed the screening criteria. The average prevalence of myosteatosis was 46.4%. Patients with myosteatosis had 44% increased mortality risk compared with non-myosteatosis patients (HR: 1.44, 95% CI: 1.33-1.55, P < .05). The predictive value of myosteatosis held regardless of country zone, study design, statistical model, Newcastle-Ottawa Scale (NOS) scores, treatment, sample size, and tumor stage. Nevertheless, the predictive value of myosteatosis was only evident for patients with esophagogastric cancers, cholangiocarcinoma/pancreatic cancers, or colorectal cancers. Overall, the results of this meta-analysis were robust based on sensitivity, subgroup, meta-regression, and trial sequential analyses and suggested that myosteatosis predicted worse overall survival (OS) in digestive malignancies patients.

Usefulness of computed tomography-measured psoas muscle thickness per height for predicting mortality in patients undergoing hemodialysis

Computed tomography (CT)-measured psoas muscle thickness standardized for height (PMTH) has emerged as a promising predictor of mortality. The study aimed to investigate whether PMTH could accurately predict mortality in patients undergoing hemodialysis. We examined 207 patients (mean age: 63.1 years; men: 66.2%) undergoing hemodialysis for more than 6 months in hospital affiliated clinic. PMTH was calculated at the L3 vertebra level using CT. Patients were divided according to the PMTH cut-off points: 8.44 mm/m in women and 8.85 mm/m in men; thereafter, they were combined into low and high PMTH groups. PMTH was independently correlated with the simplified creatinine index (β = 0.213, P = 0.021) and geriatric nutritional risk index (β = 0.295, P < 0.0001) in multivariate regression analysis. During a median follow-up of 3.7 (1.8–6.4) years, 76 patients died, including 41 from cardiovascular causes. In the multivariate Cox regression analysis, low PMTH (adjusted hazard ratio, 2.48; 95% confidence interval, 1.36–4.70) was independently associated with an increased risk of all-cause mortality. The addition of binary PMTH groups to the baseline risk model tended to improve net reclassification improvement (0.460, p = 0.060). In conclusion, PMTH may be an indicator of protein energy wasting and a useful tool for predicting mortality in patients undergoing hemodialysis.

Evaluation of skeletal muscle mass using prediction formulas at the level of the 12th thoracic vertebra

OBJECTIVES

People with cancer have a high risk of cachexia and sarcopenia, which are associated with worse clinical outcomes. We evaluated the prediction accuracy of the Matsuyama et al. and Ishida et al. formulas using computed tomography (CT) slices from the twelfth thoracic vertebra (Th12) level in people with cancer.

METHODS

This retrospective study included patients with advanced cancer who underwent thoracic and abdominal CT scans (n = 173). The cross-sectional area (CSA) on CT images was measured at the levels of Th12 and the third lumbar vertebra (L3). The Matsuyama et al. formula used the Th12 CSA, whereas the Ishida et al. formula used only the Th12 CSA of the spinal erectors; thus, the measurements were performed separately. The correlation between predicted and actual L3 CSA was assessed using r and the intraclass correlation coefficient. A prediction-accuracy analysis of the predicted values was also performed.

RESULTS

The mean participant age was 66.2 ± 12.8 y; 50.3% of participants were women and 49.7% were men. Strong correlations were observed between the predicted and measured L3 values calculated from the two prediction formulas. The prediction-accuracy analysis using previously reported cutoff values showed that the Ishida et al. method had high sensitivity and the Matsuyama et al. method had high specificity for low skeletal muscle index determined by the predicted and measured L3 skeletal muscle index.

CONCLUSIONS

Both the Matsuyama et al. and Ishida et al. formulas had good reliability on CT slices at the Th12 level in people with advanced cancer, indicating that these formulas can be applied in clinical practice.

Updated systematic review and meta-analysis on diagnostic issues and the prognostic impact of myosteatosis: A new paradigm beyond sarcopenia

Myosteatosis, which is excessive fat infiltration in the skeletal muscle, is now considered a distinct disease from sarcopenia. Advances in imaging technique have made muscle parameters an evaluable biomarker, and many studies have proved association between myosteatosis and aging or disease process. However, the diagnosis and clinical impact of myosteatosis have not been well established. Thus, we aim to provide a systematic summary with a qualitive review of 73 eligible studies regarding these issues. First, the most widely used modality to diagnose myosteatosis is abdominal computed tomography, based on evaluation of the muscle radiodensity of the total abdominal muscle area predominantly at the L3 vertebral level. However, there was significant heterogeneity in the diagnostic methods and cutoff values used to diagnose myosteatosis (32 different cutoff values among 73 studies). Second, the clinical impact of myosteatosis on prognosis was very straightforward, and most studies have shown a negative impact of myosteatosis on overall survival and complications related to underlying diseases. However, the mechanism of the myosteatosis on mortality has not been explored well, and metabolic dysfunction (i.e. insulin resistance, systemic inflammation) would be a possible explanation. Providing systemic review of current issues can elucidate future directions for developing standardized diagnosis and management of myosteatosis.

Fully Automated Deep Learning Tool for Sarcopenia Assessment on CT: L1 Versus L3 Vertebral Level Muscle Measurements for Opportunistic Prediction of Adverse Clinical Outcomes

BACKGROUND. Sarcopenia is associated with adverse clinical outcomes. CT-based skeletal muscle measurements for sarcopenia assessment are most commonly performed at the L3 vertebral level. OBJECTIVE. The purpose of this article is to compare the utility of fully automated deep learning CT-based muscle quantitation at the L1 versus L3 level for predicting future hip fractures and death. METHODS. This retrospective study included 9223 asymptomatic adults (mean age, 57 ± 8 [SD] years; 4071 men, 5152 women) who underwent unenhanced low-dose abdominal CT. A previously validated fully automated deep learning tool was used to assess muscle for myosteatosis (by mean attenuation) and myopenia (by cross-sectional area) at the L1 and L3 levels. Performance for predicting hip fractures and death was compared between L1 and L3 measures. Performance for predicting hip fractures and death was also evaluated using the established clinical risk scores from the fracture risk assessment tool (FRAX) and Framingham risk score (FRS), respectively. RESULTS. Median clinical follow-up interval after CT was 8.8 years (interquartile range, 5.1-11.6 years), yielding hip fractures and death in 219 (2.4%) and 549 (6.0%) patients, respectively. L1-level and L3-level muscle attenuation measurements were not different in 2-, 5-, or 10-year AUC for hip fracture (p = .18-.98) or death (p = .19-.95). For hip fracture, 5-year AUCs for L1-level muscle attenuation, L3-level muscle attenuation, and FRAX score were 0.717, 0.709, and 0.708, respectively. For death, 5-year AUCs for L1-level muscle attenuation, L3-level muscle attenuation, and FRS were 0.737, 0.721, and 0.688, respectively. Lowest quartile hazard ratios (HRs) for hip fracture were 2.20 (L1 attenuation), 2.45 (L3 attenuation), and 2.53 (FRAX score), and for death were 3.25 (L1 attenuation), 3.58 (L3 attenuation), and 2.82 (FRS). CT-based muscle cross-sectional area measurements at L1 and L3 were less predictive for hip fracture and death (5-year AUC ≤ 0.571; HR ≤ 1.56). CONCLUSION. Automated CT-based measurements of muscle attenuation for myosteatosis at the L1 level compare favorably with previously established L3-level measurements and clinical risk scores for predicting hip fracture and death. Assessment for myopenia was less predictive of outcomes at both levels. CLINICAL IMPACT. Alternative use of the L1 rather than L3 level for CT-based muscle measurements allows sarcopenia assessment using both chest and abdominal CT scans, greatly increasing the potential yield of opportunistic CT screening.

Short-Term Changes in Skeletal Muscle Mass After Anthracycline Administration in Adolescent and Young Adult Sarcoma Patients

Identification of anthracycline-induced muscle loss is critical for maintaining health in adolescent and young adult (AYA) cancer patients. We used routine chest computed tomography (CT) scans to investigate changes in skeletal muscle of 16 AYA sarcoma patients at thoracic vertebrae 4 (T4) after anthracycline treatment. CT images were examined at three time points (prechemotherapy, postchemotherapy, and 1 year). Significant changes in total skeletal muscle index and density were seen after chemotherapy (p = 0.021 and p = 0.016, respectively) and at 1 year versus baseline (both p < 0.05). This study supports the use of T4 as an early indicator of skeletal muscle loss in AYAs.

Body Composition as an Independent Predictive and Prognostic Biomarker in Advanced Urothelial Carcinoma Patients Treated with Immune Checkpoint Inhibitors

BACKGROUND

Several immune checkpoint inhibitors (ICIs) are approved for the treatment of advanced urothelial carcinoma (UC). There are limited biomarkers for ICI-treated patients with UC. We investigated the association between body composition and clinical outcomes in ICI-treated UC patients.

MATERIALS AND METHODS

We conducted a retrospective analysis of 70 ICI-treated patients with advanced UC at Winship Cancer Institute from 2015 to 2020. Baseline computed tomography images within 2 months of ICI initiation were collected at mid-L3 and muscle and fat compartments (subcutaneous, intermuscular, and visceral) were segmented using SliceOMatic v5.0 (TomoVision, Magog, Canada). A prognostic body composition risk score (high: 0-1, intermediate: 2-3, or low-risk: 4) was created based on the β coefficient from the multivariate Cox model (MVA) following best-subset variable selection. Our body composition risk score was skeletal muscle index (SMI) + 2 × attenuated skeletal muscle (SM) mean + visceral fat index (VFI). Concordance statistics (C-statistics) were used to quantify the discriminatory magnitude of the predictive model.

RESULTS

Most patients (70%) were men and the majority received ICIs in the second- (46%) or third-line (21%) setting. High-risk patients had significantly shorter overall survival (OS; hazard ratio [HR], 6.72; p < .001), progression-free survival (HR, 5.82; p < .001), and lower chance of clinical benefit (odds ratio [OR], 0.02; p = .003) compared with the low-risk group in MVA. The C-statistics for our body composition risk group and myosteatosis analyses were higher than body mass index for all clinical outcomes.

CONCLUSION

Body composition variables such as SMI, SM mean, and VFI may be prognostic and predictive of clinical outcomes in ICI-treated patients with UC. Larger, prospective studies are warranted to validate this hypothesis-generating data.

IMPLICATIONS FOR PRACTICE

This study developed a prognostic body composition risk scoring system using radiographic biomarkers for patients with bladder cancer treated with immunotherapy. The study found that the high-risk patients had significantly worse clinical outcomes. Notably, the study's model was better at predicting outcomes than body mass index. Importantly, these results suggest that radiographic measures of body composition should be considered for inclusion in updated prognostic models for patients with urothelial carcinoma treated with immunotherapy. These findings are useful for practicing oncologists in the academic or community setting, particularly given that baseline imaging is routine for patients starting on treatment with immunotherapy.

Comparison of muscle mass and quality between metabolically healthy and unhealthy phenotypes

OBJECTIVE

The aim of this study was to examine whether higher skeletal muscle mass is associated with a metabolically healthy phenotype and whether muscle quality affects metabolic health.

METHODS

This cross-sectional analysis included 20,659 participants (7,966 women) who underwent abdominal computed tomography scans during health checkups. The total abdominal muscle area (TAMA) on the third lumbar vertebral level was demarcated. Intermuscular adipose tissue and skeletal muscle area were measured. The skeletal muscle area was divided into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). The NAMA/TAMA index was calculated. The metabolically unhealthy phenotype was defined as having two or more components of metabolic syndrome or the presence of hypertension or diabetes.

RESULTS

TAMA and skeletal muscle area were not significantly different or even lower in metabolically healthy phenotypes compared with metabolically unhealthy phenotypes. However, metabolically healthy phenotypes had significantly higher NAMA (except in women with obesity) and NAMA/TAMA index than in the metabolically unhealthy phenotypes. In people without obesity, lower NAMA/TAMA index was independently associated with higher risk of the metabolically unhealthy phenotype in the fully adjusted model.

CONCLUSIONS

The metabolically healthy phenotypes had more good-quality muscles than did the metabolically unhealthy phenotypes. These results suggest that not only muscle mass but also muscle quality (i.e., degree of myosteatosis) are associated with metabolic health.

Body composition in patients with type 2 intestinal failure

BACKGROUND

Measurement of body composition is a valuable clinical tool for nutrition assessments, but there are no data on the merits of assessment modalities in type 2 intestinal failure (IF). The aim of this study was to evaluate the prevalence of low muscle mass and quality in type 2 IF, comparing bioelectric impedance analysis (BIA) and computed tomography (CT) at the third lumbar vertebra level.

METHODS

Patients admitted with acute severe (type 2) IF to a national UK IF center who had BIA measurement and CT scan as part of routine care within 40 days of anthropometric measurement were included in this cross-sectional study. Data were also collected on patient demographics and clinical characteristics.

RESULTS

Forty-four patients meeting inclusion criteria were included. Low muscle mass was detected in 37 out of 44 (84.1%) patients by CT scan and in 30 of out 44 (68.2%) by BIA. Low muscle quality was detected in 22 out of 44 (50%) patients by CT scan and in 40 out of 44 (90.1%) by BIA. Comparison of CT and BIA measurements showed a moderate correlation of muscle, Spearman ρ 0.65 (95% CI, 0.42-0.81; P < 0.001), and a strong correlation of body fat mass measurements, Spearman ρ 0.79 (95% CI, 0.62-0.89; P < 0.001).

CONCLUSION

This is the first study to demonstrate that low muscle mass is common in patients with type 2 IF, regardless of body composition assessment modality. A larger cohort study is required to validate the impact of low muscle mass and quality on clinical outcomes and the role of targeted interventions to improve the care of patients with type 2 IF.

Muscle Mass Assessed by the D3-Creatine Dilution Method and Incident Self-reported Disability and Mortality in a Prospective Observational Study of Community-Dwelling Older Men

BACKGROUND

Whether low muscle mass is a risk factor for disability and mortality is unclear. Associations between approximations of muscle mass (including lean mass from dual-energy x-ray absorptiometry [DXA]), and these outcomes are inconsistent.

METHODS

Muscle mass measured by deuterated creatine (D3Cr) dilution and appendicular lean mass (ALM, by DXA) were assessed at the Year 14 Visit (2014-2016) of the prospective Osteoporotic Fractures in Men study (N = 1,425, age 77-101 years). Disability in activities of daily living (ADLs), instrumental ADLs, and mobility tasks was self-reported at the Year 14 visit and 2.2 years later; deaths were centrally adjudicated over 3.3 years. Relative risks and 95% confidence intervals (CI) were estimated per standard deviation decrement with negative binomial, logistic regression, or proportional hazards models.

RESULTS

In age- and clinical center-adjusted models, the relative risks per decrement in D3Cr muscle mass/wgt was 1.9 (95% CI: 1.2, 3.1) for incident self-reported ADL disability; 1.5 (95% CI: 1.3, 1.9) for instrumental ADL disability; and 1.8 (95% CI: 1.5, 2.2) for mobility disability. In age-, clinical center-, and weight-adjusted models, the relative risks per decrement in D3Cr muscle mass was 1.8 (95% CI: 1.5, 2.2) for all-cause mortality. In contrast, lower DXA ALM was not associated with any outcome. Associations of D3Cr muscle mass with these outcomes were slightly attenuated after adjustment for confounding factors and the potentially mediating effects of strength and physical performance.

CONCLUSIONS

Low muscle mass as measured by D3Cr dilution is a novel risk factor for clinically meaningful outcomes in older men.

Reference Data and T-Scores of Lumbar Skeletal Muscle Area and Its Skeletal Muscle Indices Measured by CT Scan in a Healthy Korean Population

BACKGROUND

Although computed tomography (CT) is considered the gold standard for investigating skeletal muscles, diagnostic cutoff points for sarcopenia have not been established. We therefore suggested clinically relevant diagnostic cutoff points for sarcopenia based on reference values of skeletal muscle area (SMA) measured by CT scan in a large-sized healthy Asian population.

METHODS

This cross-sectional analysis included 11,845 subjects (7,314 men, 4,531 women) who underwent abdominal CT scans in South Korea. SMA including all muscles on the selected axial images of the L3 lumbar vertebrae level was demarcated using predetermined thresholds (-29 to +150 Hounsfield units). SMA indices (height-, weight-, and body mass index [BMI]-adjusted) were calculated.

RESULTS

When T-score < -2.0 was used as the cutoff for defining sarcopenia, the sex-specific cutoff points of SMA, SMA/height2, SMA/weight, and SMA/BMI were 119.3 and 74.2 cm2, 39.8 and 28.4 cm2/m2, 1.65 and 1.38 cm2/kg, and 4.97 and 3.46 in men and women, respectively. In both sexes, the SMA/BMI values peaked in the 20s and decreased gradually. The SMA/BMI yielded the highest diagnostic rate of sarcopenia (4.2% in men, 8.7% in women), while SMA/height2 provided the lowest yield (2.8% in men, 1.0% in women).

CONCLUSIONS

This is the first study to report the reference values of SMA and skeletal muscle indices (SMIs) measured on CT scans and to suggest cutoff points for diagnosis of sarcopenia based on T-score in Asian subjects. BMI-adjusted index (SMA/BMI) was the best index of CT-measured SMA to reflect the age-related muscle changes and to maximize the diagnostic yield for sarcopenia.

Investigation of the prognostic value of psoas muscle area measurement in pediatric patients before liver transplantation: A single-center retrospective study

BACKGROUND

In this study, our aim is to investigate the prognostic value of psoas muscle area (PMA) evaluation before liver transplantation (LT) in pediatric patients.

METHODS

Two hundred seventy-six patients under 18 years of age who underwent LT between January 2012 and December 2019 were included in the study. The patients' demographic, laboratory, clinical, and imaging data were scanned retrospectively. PMA was measured at the L4/5 level using computed tomography images. To determine reproducibility, a different radiologist evaluated 30 randomly selected patients.

RESULTS

In patients with end-stage liver disease (ESLD), PMA was significantly lower than in patients with acute liver failure (P < .001). In patients with ESLD, a weakly significant correlation was found between PMA and 1-year survival after LT (r: .251, P = .030), hospitalization period (r: -.275, P = .039), and pediatric ESLD score (r: -.338, P < .001). Interobserver correlation was excellent (ICC: .941, 95% CI: .925, .971).

CONCLUSION

In children with ESLD, PMA evaluated before LT can be used as a negative prognostic factor.

Low skeletal muscle density combined with muscle dysfunction predicts adverse events after adult cardiovascular surgery

BACKGROUND AND AIMS

Although muscle dysfunctions are widely known as a poor prognostic factor in patients with cardiovascular disease, no study has examined whether the addition of low skeletal muscle density (SMD) assessed by computed tomography (CT) to muscle dysfunctions is useful. This study examined whether SMDs can strengthen the predictive ability of muscle dysfunctions for adverse events in patients who underwent cardiovascular surgery.

METHODS AND RESULTS

We retrospectively reviewed 853 patients aged ≥40 years who had preoperative CT for risk management purposes and who measured muscle dysfunctions (weakness: low grip strength and slowness: slow gait speed). Low SMD based on transverse abdominal CT images was defined as a mean Hounsfield unit of the psoas muscle <45. All definitions of muscle dysfunction (weakness only, slowness only, weakness or slowness, weakness and slowness), the addition of SMDs was shown to significantly improve the continuous net reclassification improvement and integrated discrimination improvement for adverse events in all analyses (p < 0.05). Low SMDs combined with each definition of muscle dysfunction had the highest risk of all-cause death (hazard ratio: lowest 3.666 to highest 6.002), and patients with neither low SMDs nor muscle dysfunction had the lowest risk of all-cause and cardiovascular-related events.

CONCLUSION

The addition of SMDs consistently increased the predictive ability of muscle dysfunctions for adverse events. Our results suggest that when CT is performed for any clinical investigation, the addition of the organic assessment of skeletal muscle can strengthen the diagnostic accuracy of muscle wasting.

Comparison of ultrasound speed-of-sound of the lower extremity and lumbar muscle assessed with computed tomography for muscle loss assessment

To compare the speed of propagation of ultrasound (US) waves (SoS) of the lower leg with the clinical reference standard computed tomography (CT) at the level of lumbar vertebra 3 (L3) for muscle loss assessment. Both calf muscles of 50 patients scheduled for an abdominal CT were prospectively examined with ultrasound. A plexiglas-reflector located on the opposite side of the probe with the calf in between was used as a timing reference for SoS (m/s). CT measurements were performed at the level of L3 and included area (cm2) and attenuation (HU) of the psoas muscle, abdominal muscles, subcutaneous fat, visceral fat and abdominal area. Correlations between SoS, body mass index (BMI) and CT were determined using Pearson's correlation coefficient. Based on reported CT sarcopenia threshold values, receiver operating characteristic (ROC) analysis was performed for SoS. Inter-examiner agreement was assessed with the median difference, inter-quartile range (IQR) and intraclass correlation coefficients. SoS of the calf correlated moderately with abdominal muscle attenuation (r = 0.48; P < .001), psoas muscle attenuation (r = 0.40; P < .01), abdominal area (r = -0.44; P < .01) and weakly with subcutaneous fat area (r = -0.37; P < .01). BMI correlated weakly with psoas attenuation (r = -0.28; P < .05) and non-significantly with abdominal muscle attenuation. Normalization with abdominal area resulted in moderate correlations with abdominal muscle area for SoS (r = 0.43; P < .01) and BMI (r = -0.46; P < .001). Based on sarcopenia threshold values for skeletal muscle attenuation (SMRA), area under curve (AUC) for SoS was 0.724. Median difference between both examiners was -3.4 m/s with IQR = 15.1 m/s and intraclass correlation coefficient = 0.794. SoS measurements of the calf are moderately accurate based on CT sarcopenia threshold values, thus showing potential for muscle loss quantification.

Computed tomography (CT)-defined sarcopenia and myosteatosis are prevalent in patients with neuroendocrine neoplasms (NENs) treated with peptide receptor radionuclide therapy (PRRT)

BACKGROUND/OBJECTIVES

Neuroendocrine neoplasms (NEN) may predispose patients to malnutrition. CT-defined sarcopenia and myosteatosis are common in other tumour types and recognized adverse prognostic factors. However, the prevalence and prognostic impact of sarcopenia and myosteatosis remain undetermined in NEN patients to date.

METHODS

A retrospective study of NEN patients treated with peptide receptor radionuclide therapy (PRRT) at a tertiary institution from 2012 to 2017. Patients with PET/CT imaging at baseline and follow-up were included. The L3 slice of the co-localizing CT was analysed using the Alberta Protocol. Skeletal muscle cross-sectional area and muscle attenuation were measured and compared with pre-defined cut-offs. The primary endpoint was the prevalence of sarcopenia and myosteatosis according to previously published cut-offs.

RESULTS

Fourty-nine patients (median age 64 (range 26-80) years) were included. The most common primary sites of tumour were the small bowel (51%) and pancreas (26%). Baseline sarcopenia was prevalent in 67% of patients and myosteatosis in 71%. Forty-five percent of patients gained weight over the course of PRRT. The presence of baseline sarcopenia was not associated with progression-free survival (20.8 mo vs. 20.7 mo, HR 0.86, p = 0.70) nor overall survival. Similarly, baseline myosteatosis (PFS 19.5 mo vs. 20.8 mo, HR 0.77, p = 0.47) was not significantly associated with survival outcomes. The mean (SD) age of those with myosteatosis was 60.8 ± 11.6 years compared to 49.7 ± 12.7 years for those without (p = 0.003).

CONCLUSIONS

Body composition analysis is feasible using routinely acquired PET/CT data for patients with NEN. CT-defined sarcopenia and myosteatosis are prevalent in NEN patients, although myosteatosis is more common with increasing age. These findings were not associated with worsened overall or progression-free survival in the current study.

Age-related changes in muscle quality and development of diagnostic cutoff points for myosteatosis in lumbar skeletal muscles measured by CT scan

BACKGROUND & AIMS

We have sought to develop proper and useful indices for muscle quality measurements other than muscle attenuation (Hounsfield unit; HU) and to determine the diagnostic cutoff points for myosteatosis by using those indices measured at the L3 lumbar vertebrae level by CT scan.

METHODS

This cross-sectional analysis included 20,664 healthy adult subjects (12,697 men and 7967 women) who underwent abdominal CT scans. Total abdominal muscle area (TAMA), on the L3 vertebra was demarcated using predetermined thresholds. Intermuscular adipose tissue area (IMAT) and skeletal muscle area (SMA) were measured. SMA was divided into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). Their various indices were calculated. We identified the sex-specific mean values of NAMA, LAMA, IMAT, and their indices and the cutoff points equivalent to the T-scores in the young reference group.

RESULTS

The mean values of the NAMA and NAMA indices decreased with age in both sexes, LAMA, IMAT, and their indices showed an increasing tendency with age in both sexes. When using T-score < -2.0 as the cutoff for myosteatosis, the sex-specific cutoff points of NAMA, NAMA/BMI, NAMA/TAMA index, and SMA and TAMA attenuation in men and women were 103.0 and 64.5 cm², 4.0 and 2.8, 66.4 and 65.1, 40.2 and 39.9 HU, and 34.1 and 33.5 HU, respectively. Using these cutoff points, the prevalence of myosteatosis by NAMA, NAMA/BMI, NAMA/TAMA index, or SMA or TAMA attenuation ranged from 5.9 to 8.8% in men and from 10.2 to 20.5% in women.

CONCLUSIONS

The NAMA/TAMA index developed in this study was useful for assessing myosteatosis. This is the first study to report the sex-specific diagnostic cutoff points for myosteatosis of trunk muscles based on T-scores measured by CT scans in healthy population. These diagnostic cutoff points may be particularly useful in the treatment and prevention of sarcopenia and myosteatosis.

Body composition by computed tomography vs. dual energy x-ray absorptiometry: Long-term prediction of all-cause mortality in the Health ABC cohort

BACKGROUND

Body composition assessment by computed tomography (CT) predicts health outcomes in diverse populations. However, its performance in predicting mortality has not been directly compared to dual-energy-X-ray-absorptiometry (DXA). Additionally, the association between different body compartments and mortality, acknowledging the compositional nature of human body, is not well-studied. Compositional Data Analysis, that is applied to multivariate proportion-type dataset, may help to account for the inter-relationships of body compartments by constructing log-ratios of components. Here, we determined the associations of baseline CT-based measures of mid-thigh cross-sectional areas vs. DXA measures of body composition with all-cause mortality in Health ABC cohort, using both traditional (individual body compartments) and Compositional Data Analysis (using ratios of body compartments) approaches.

METHODS

The Health ABC study assessed body composition in 2911 older adults in 1996-97. We investigated the individual and ratios of (by Compositional Analysis) body compartments assessed by DXA (lean, fat, and bone-mass) and CT (muscle, subcutaneous fat area, intermuscular fat (IMF), and bone) on mortality, using Cox proportional hazard models.

RESULTS

Lower baseline muscle area by CT (HRmen=0.56 [95%CI: 0.48-0.67], HRwomen=0.60 [0.48-0.74]), fat-mass by DXA (HRmen=0.48 [0.24-0.95]) were predictors of mortality in traditional Cox-regression analysis. Consistently, Compositional Data Analysis revealed that lower muscle area vs. IMF, muscle area vs. bone area, and lower fat-mass vs. lean-mass were associated with higher mortality in both sexes.

CONCLUSION

Both CT measure of muscle area and DXA fat-mass (either individually or relative to other body compartments) were strong predictors of mortality in both sexes in a community research setting.

Diagnosing sarcopenia at the point of imaging care: analysis of clinical, functional, and opportunistic CT metrics

OBJECTIVE

To determine the relationship between CT-derived muscle metrics and standardized metrics of sarcopenia in patients undergoing routine CT imaging.

MATERIALS AND METHODS

Data collected in 443 consecutive patients included body CT, grip strength, usual gait speed, and responses to SARC-F and FRAIL scale questionnaires. Functional and clinical metrics of sarcopenia were acquired at the time of CT. Metrics were analyzed using the diagnostic framework of the European Working Group on Sarcopenia in Older People (EWGSOP2). The skeletal muscle index (SMI) and skeletal muscle density (SMD) were measured at the T12 and L3 levels. Statistical methods include linear prediction models and ROC analysis.

RESULTS

T12-SMD and L3-SMD in women and T12-SMD and L3-SMI in men show weak but significant (p < 0.05) predictive value for gait speed, after adjusting for subject age and body mass index. The prevalence of abnormal CT SMI at T12 and L3 was 29% and 71%, respectively, corresponding to prevalences of confirmed sarcopenia by EWGSOP2 of 10% and 15%, respectively. The agreement of abnormal SARC-F and FRAIL scale screening and EWGSOP2 confirmed sarcopenia was slight to fair (kappa: 0.20-0.28). CT cutpoints, based on EWGSOP2 criteria for abnormal grip strength or gait speed, are generally lower than cutpoints based on normative population data.

CONCLUSION

Collection of clinical and functional sarcopenia information at the point of imaging care can be accomplished quickly and safely. CT-derived muscle metrics show convergent validity with gait speed. Only a minority of subjects with low CT metrics have confirmed sarcopenia by EWGSOP2 definition.

The Association Between Computed Tomography-Defined Sarcopenia and Outcomes in Adult Patients Undergoing Radiotherapy of Curative Intent for Head and Neck Cancer: A Systematic Review

BACKGROUND

Computed tomography (CT)-defined sarcopenia is a demonstrated poor prognostic factor in patients with cancer; however, its influence on outcomes for patients with head and neck cancer (HNC) has not been established.

OBJECTIVE

This review synthesizes current knowledge regarding the association between CT-defined sarcopenia and outcomes for adult patients undergoing radiotherapy with or without other treatment modalities of curative intent for HNC.

METHODS

A systematic review of the literature published between January 2004 and June 2019 was conducted in Medline, Embase, Cumulative Index of Nursing and Allied Health Literature, Allied and Complementary Medicine Database, and PubMed. Empirical studies of CT-defined sarcopenia in adult patients (≥18 years) with HNC who had completed radiotherapy of curative intent with or without other treatment modalities were included. Outcomes reported included survival, prolonged radiotherapy breaks, and chemotherapy toxicity. Study quality was assessed using the American Academy of Nutrition and Dietetics Quality Criteria Checklist. Synthesis of outcomes and clinical relevance was performed using the Grading of Recommendations Assessment, Development, and Evaluation system.

RESULTS

Of 11 studies (n = 3,461) identified, 3 were positive and 8 were neutral quality. Studies were heterogeneous in HNC diagnosis, ethnicity, definition of sarcopenia, CT level of evaluation, and skeletal muscle index threshold value. Eight definitions for sarcopenia were identified with pretreatment prevalence of 6.6% to 70.9% and posttreatment prevalence of 12.4% to 65.8%. Pretreatment sarcopenia was independently associated with reduced: overall survival (OS), 3-year OS, disease-free survival, prolonged radiotherapy breaks, and chemotherapy-related toxicities. Posttreatment sarcopenia was independently associated with reduced OS and 5-year OS. The overall certainty of evidence according to Grading of Recommendations Assessment, Development and Evaluation criteria was low for OS; 3-year, 5-year, and 10-year OS; locoregional control; locoregional failure; progression-free survival; metastasis-free survival, disease-specific survival; and disease-free survival and very low for distant metastasis, prolonged radiotherapy breaks, and chemotherapy toxicity-related outcomes.

CONCLUSIONS

CT-defined sarcopenia is independently associated with reduced OS and treatment completion in patients with HNC and holds a clinically meaningful prognostic value. The certainty of the evidence requires strengthening with further research. Understanding the impact sarcopenia has on outcomes for these patients has implications for informing potential nutrition interventions and facilitating individualized care.

Trunk Skeletal Muscle Changes on CT with Long-Duration Spaceflight

Astronauts exposed to microgravity for extended time are susceptible to trunk muscle atrophy, which may compromise strength and function on mission and after return. This study investigates changes in trunk skeletal muscle size and composition using computed tomography (CT) and dual-energy X-ray absorptiometry (DXA) among 16 crewmembers (1 female, 15 male) on 4-6 month missions. Muscle cross-sectional area and muscle attenuation were measured using abdominal CT scans at pre-flight, post-flight return, 1 year post-flight, and 2-4 years post-flight. Longitudinal muscle changes were analyzed using mixed models. In six crewmembers, CT and DXA data were used to calculate subject height-normalized skeletal muscle indices. Changes in these indices were analyzed using paired t-tests and compared by imaging modality using Pearson correlations. Trunk muscle area decreased at post-flight return (- 4.7 ± 1.1%, p < 0.001) and recovered to pre-flight values at 1-4 years post-flight. Muscle attenuation changes were not significant. Skeletal muscle index from CT decreased (- 5.2 ± 1.0%, p = 0.004) while appendicular skeletal muscle index from DXA did not change significantly. In summary, trunk muscle atrophies with long-duration microgravity exposure but recovers to pre-flight values within 1-4 years. The CT measures highlight size decreases not detected with DXA, emphasizing the importance of advanced imaging modalities in assessing muscle health with spaceflight.

Development and validation of nomograms for the prediction of low muscle mass and radiodensity in gastric cancer patients

BACKGROUND

The skeletal muscle mass index (SMI) and skeletal muscle radiodensity (SMD) are important components of sarcopenia and malnutrition. However, their assessment requires additional resources in cancer patients, which is inconvenient for the early detection of sarcopenia and malnutrition.

OBJECTIVES

This study aimed to develop and validate nomograms for the prediction of low muscle mass and muscle radiodensity and to examine the application value of the nomograms in the diagnoses of sarcopenia and malnutrition.

METHODS

A total of 1315 patients diagnosed with gastric cancer between July 2014 and May 2019 were included. Random resampling with an 80/20 split ratio was performed to obtain a training cohort (n = 1056) and a validation cohort (n = 259). Nomograms were separately constructed for low SMI (LSMI) and low SMD (LSMD) in the training cohort based on prospectively collected preoperative data. The performance of the nomograms was assessed using the AUC, calibration curve, and Hosmer-Lemeshow test. The application values of the nomograms in the diagnoses of sarcopenia and malnutrition were also evaluated.

RESULTS

Age, BMI, hemoglobin concentration, and gait speed were included in the nomogram for LSMI predictions. These variables, in addition to sex, were included in the nomogram for LSMD predictions. The diagnostic nomograms exhibited good discrimination, with AUCs of 0.818 (95% CI, 0.791-0.845) for the LSMI nomogram and 0.788 (95% CI, 0.761-0.815) for the LSMD diagnostic nomogram in the training cohort. Calibration was also excellent. The agreement ratios between the nomograms and actual observations in the total population were 92.3% and 95.6% for sarcopenia and malnutrition, respectively. Prognostic nomograms exhibited similar performance in the validation cohort.

CONCLUSIONS

Diagnostic nomograms consisting of preoperative factors can successfully predict LSMI and LSMD. These models facilitate early identification and timely interventions for at-risk populations.