Feasibility of assessment of skeletal muscle mass on a single cross-sectional image at the level of the fourth thoracic vertebra

Vertebral HU value and the pectoral muscle index based on chest CT can be used to opportunistically screen for osteoporosis

BACKGROUND

Existing studies have shown that computed tomography (CT) attenuation and skeletal muscle tissue are strongly associated with osteoporosis; however, few studies have examined whether vertebral HU values and the pectoral muscle index (PMI) measured at the level of the 4th thoracic vertebra (T4) are strongly associated with bone mineral density (BMD). In this study, we demonstrate that vertebral HU values and the PMI based on chest CT can be used to opportunistically screen for osteoporosis and reduce fracture risk through prompt treatment.

METHODS

We retrospectively evaluated 1000 patients who underwent chest CT and DXA scans from August 2020-2022. The T4 HU value and PMI were obtained using manual chest CT measurements. The participants were classified into normal, osteopenia, and osteoporosis groups based on the results of dual-energy X-ray (DXA) absorptiometry. We compared the clinical baseline data, T4 HU value, and PMI between the three groups of patients and analyzed the correlation between the T4 HU value, PMI, and BMD to further evaluate the diagnostic efficacy of the T4 HU value and PMI for patients with low BMD and osteoporosis.

RESULTS

The study ultimately enrolled 469 participants. The T4 HU value and PMI had a high screening capacity for both low BMD and osteoporosis. The combined diagnostic model-incorporating sex, age, BMI, T4 HU value, and PMI-demonstrated the best diagnostic efficacy, with areas under the receiver operating characteristic curve (AUC) of 0.887 and 0.892 for identifying low BMD and osteoporosis, respectively.

CONCLUSIONS

The measurement of T4 HU value and PMI on chest CT can be used as an opportunistic screening tool for osteoporosis with excellent diagnostic efficacy. This approach allows the early prevention of osteoporotic fractures via the timely screening of individuals at high risk of osteoporosis without requiring additional radiation.

Sarcopenia as a Predictor of Feeding Tube Placement in Individuals with Oropharyngeal Cancer

Purpose

In oropharyngeal squamous cell carcinoma (OPSCC), systemic loss of skeletal muscle mass (SMM), or sarcopenia, is a strong prognostic predictor of survival outcomes. However, the relationship between sarcopenia and nutrition-related outcomes is not well understood. This investigation evaluated the prognostic significance of sarcopenia for feeding tube (FT) placement in a cohort of OPSCC patients.

Methods and Materials

A retrospective cohort study was conducted with data collected from 194 OPSCC patients treated with definitive radiation therapy (RT) or chemoradiation therapy (CRT). Sarcopenia was assessed from computed tomography imaging at the level of the third cervical (C3) and fourth thoracic (T4) vertebrae. The prognostic nature of pretreatment sarcopenia and its relationship with FT placement was explored using logistic regression.

Results

The median age of patients included was 61.0 years, and the majority were male (83%). In this patient cohort, 87.6% underwent concurrent CRT, and 30.9% received a FT over the course of treatment. Sarcopenia was identified at baseline in 72.7% of patients based on C3 SMM measurements and in 41.7% based on measures at the level of T4. Based on measures at both C3 and T4, those with sarcopenia were significantly more likely to receive a FT and had significantly worse freedom from FT placement compared with patients without sarcopenia. Sarcopenia assessed at T4 was a significant predictor of FT placement.

Conclusions

SMM measured at T4 may represent a novel and practical biomarker for sarcopenia detection that is associated with the need for FT placement. These findings suggest that the detection of baseline sarcopenia could guide decision-making related to the need for nutritional support in OPSCC patients undergoing RT/CRT.

Cardiovascular Imaging-Derived Skeletal Muscle Mass Correlates With Fitness and Survival in Patients With Univentricular Circulation

Aims This study aims to retrospectively quantify skeletal muscle mass from cardiovascular imaging studies in total cavopulmonary connection (TCPC) patients and to correlate calculated muscle mass with clinical outcomes. Materials and methods Ninety-one TCPC patients at a mean age of 24.0 ±5.5 years (37 women; 40.7%) who underwent chest computed tomography (CT) or cardiac magnetic resonance imaging (MRI) as part of their follow-up were identified in a single-center database. The cross-sectional skeletal muscle index (SMI) at the Th4 and Th12 levels was calculated from CT images, and the dorsal skeletal muscle area (SMA) at the Th12 level was measured from an MRI. Results Calculated SMI at Th12 level was 38.0 (34.5; 42.0) cm2.m-2 or 89.6 (81.9; 101.6) % of predicted values. The median follow-up from CT was 5.9 (3.1; 8.5) years, and the composite endpoint (death N=5, heart transplant N=6) was reached in a total of 11 (26.8%) patients. Patients with SMI (Th12) less than 90% of predicted values had a hazard ratio of 5.8 (95% CI: 1.2; 28.3) (p=0.03) for endpoint achievement. In the MRI group, dorsal SMA at the Th12 level was 27.6 ±5.1 cm2 in men and 20.0 ±5.8 cm2 in women. Correlations were found between SMA/kg and peak oxygen uptake (VO2 peak) (r=0.48, p=0.0005) and fat-free mass (r=0.63, p<0.0001), respectively. Conclusions A low SMI at the Th12 level was associated with a higher risk of death or cardiac transplantation. Evaluation of skeletal muscle mass using cardiovascular imaging methods allows rapid identification of individuals at risk of sarcopenia.

Combined Prognostic Impact of Low Muscle Mass and Hypoalbuminemia in Patients Hospitalized for Heart Failure: A Retrospective Cohort Study

BACKGROUND

Sarcopenia and hypoalbuminemia have been identified as independent predictors of increased adverse outcomes, including mortality and readmissions, in hospitalized older adults with acute decompensated heart failure (ADHF). However, the impact of coexisting sarcopenia and hypoalbuminemia on morbidity and death in adults with ADHF has not yet been investigated. We aimed to investigate the combined effects of lower muscle mass (LMM) as a surrogate for sarcopenia and hypoalbuminemia on in-hospital and postdischarge outcomes of patients hospitalized for ADHF.

METHODS AND RESULTS

A total of 385 patients admitted for ADHF between 2017 and 2020 at a single institution were retrospectively identified. Demographic and clinical data were collected, including serum albumin levels at admission and discharge. Skeletal muscle indices were derived from semi-automated segmentation software analysis on axial chest computed tomography at the twelfth vertebral level. Our analysis revealed that patients who had LMM with admission hypoalbuminemia experienced increased diagnoses of infection and delirium with longer hospital length of stay and more frequent discharge to a facility. Upon discharge, 27.9% of patients had higher muscle mass without discharge hypoalbuminemia (reference group), 9.7% had LMM without discharge hypoalbuminemia, 38.4% had higher muscle mass with discharge hypoalbuminemia, and 24.0% had LMM with discharge hypoalbuminemia; mortality rates were 37.6%, 51.4%, 48.9%, and 63.2%, respectively. 1- and 3-year mortality risks were highest in those with LMM and discharge hypoalbuminemia; this relationship remained significant over a median 23.6 (3.1-33.8) months follow-up time despite multivariable adjustments (hazard ratio, 2.03 [95% CI, 1.31-3.16]; P=0.002).

CONCLUSIONS

Hospitalization with ADHF, LMM, and hypoalbuminemia portend heightened mortality risk.

Significance of Adipose Tissue Quantity and Distribution on Obesity Paradox in Heart Failure

Obesity is a predictor of the development of systolic and diastolic heart failure (HF), but once established, patients with HF and obesity have better outcomes than their leaner counterparts, a phenomenon termed the "obesity paradox." We sought to investigate the impact of adipose tissue quantity and distribution, measured by way of computed tomography, on outcomes in patients with HF. Patients admitted for acute decompensated HF between January 2017 to December 2018 were retrospectively analyzed. Body composition measurements were made on computed tomography of the abdomen/pelvis. Visceral, subcutaneous, and intermuscular adipose tissues were measured at the mid-third lumbar vertebra, along with skeletal muscle and waist circumference. Paracardial (pericardial and epicardial) adipose tissue was measured at the mid-eight thoracic vertebra. Visceral adipose tissue index (VATI) and subcutaneous adipose tissue index (SATI), along with skeletal muscle index, were indexed for patient height. A total of 200 patients were included, 44.5% female. Body mass index and waist circumference did not significantly predict outcomes. Patients with high SATI (highest sex-stratified tertile) had significantly better survival (hazard ratio 0.58, 95% confidence interval 0.39 to 0.87, p = 0.009), whereas high VATI was nonsignificant. Patients were further divided into 4 groups based on both VATI and SATI. One- and 4-year mortality risks were lowest in those with low VATI high SATI compared with the other groups; this persisted after multivariable adjustment for covariates, including albumin and skeletal muscle index. In conclusion, the "obesity paradox" appears to be largely driven by subcutaneous adipose tissue, independent of nutrition or skeletal muscle.

The use of the second thoracic vertebral landmark for skeletal muscle assessment and computed tomography-defined sarcopenia evaluation in patients with head and neck cancer

BACKGROUND

The cross-sectional area (CSA) of skeletal muscle (SM) at the third lumbar vertebra (L3) is used to determine computed tomography (CT)-defined sarcopenia. We investigated the feasibility of SM assessment at the second thoracic vertebra (T2) in patients with head and neck cancer (HNC).

METHODS

Diagnostic PET-CT scans were used to develop a prediction model for L3-CSA using T2-CSA. Effectiveness of the model and cancer-specific survival (CSS) were investigated.

RESULTS

Scans of 111 patients (85% male) were evaluated. The predictive formula: L3-CSA (cm² ) = 174.15 + [0.212 × T2-CSA (cm² )] - [40.032 × sex] - [0.928 × age (years)] + [0.285 × weight (kg)] had good correlation r = 0.796, ICC = 0.882 (p < 0.001). SM index (SMI) mean difference (bias) was -3.6% (SD 10.2, 95% CI -8.7% to 1.3%). Sensitivity (82.8%), specificity (78.2%), with moderate agreement (ƙ = 0.540, p < 0.001). Worse 5-year CSS with lower quartile T2-SMI (51%, p = 0.003).

CONCLUSIONS

SM at T2 can be effectively used for CT-defined sarcopenia evaluation in HNC.

Comparison of Skeletal Muscle Changes at Three Vertebral Levels Following Radiotherapy in Patients With Oropharyngeal Carcinoma

Evaluation of skeletal muscle (SM) depletion, or sarcopenia, utilizes the cross-sectional area (CSA) of computed tomography (CT) scans at the lumbar level L3. However, alternate vertebral landmarks are used in patients with head and neck cancer due to scan unavailability. Muscle changes following radiotherapy at cervical (C3) and thoracic (T2) levels were compared to L3 in patients with oropharyngeal carcinoma. Muscle density data were derived retrospectively from diagnostic PET-CT scans at C3, T2 and L3 pretreatment, and up to six months post. CSA changes were compared to L3 in scans of 33 patients (88% male, mean age 61 (SD 8.5) years). On matched pair analysis; mean L3-CSA change -12.1 cm² (SD 9.7, 95%CI -15.5 to -8.6, and p < 0.001), T2-CSA -30.5 cm² (SD 34.8, 95%CI -42.8 to -18.1, and p < 0.001) and C3-CSA +2.1 cm² (SD 4.1, 95%CI 0.63 to 3.5, and p < 0.00). No difference was found in the percentage change of T2-CSA with L3-CSA (mean -2.2%, SD 10.6, 95%CI -6.0 to 1.6, and p = 0.240), however, was significantly different to C3-CSA (mean 13.2%, SD 11.6, 95%CI 9.1 to 17.3, and p < 0.001). Results suggest SM at C3 does not change proportionately and may not be a reliable representation of whole-body SM change over time.

The validation of low-dose CT scans from the [18F]-FDG PET-CT scan to assess skeletal muscle mass in comparison with diagnostic neck CT scans

PURPOSE

Radiologically defined sarcopenia, or a low skeletal muscle index (SMI), is an emerging biomarker for adverse clinical outcomes in head and neck cancer (HNC) patients. Recently, SMI measurements have been validated at the level of the third cervical vertebra (C3) on diagnostic neck CT scans but are not yet validated on low-dose (LD) neck CT scans from the [¹⁸F]-FDG PET-CT. This hampers SMI analysis in HNC patients without a diagnostic neck CT but with a [¹⁸F]-FDG PET-CT scan. Therefore, the aim was to study whether (low) SMI based on LD CT scan from [¹⁸F]-FDG PET-CT is comparable to those derived from diagnostic neck CT scans.

METHODS

HNC patients with both diagnostic CT and [¹⁸F]-FDG PET-CT of the neck were prospectively included into the OncoLifeS data-biobank. Skeletal muscle was retrospectively delineated at the level of the third cervical vertebra (C3), and (low) SMI (cm²/m²) was calculated for diagnostic and LD neck CTs. (Low) SMI from the diagnostic neck CT was considered the reference standard. Intra-class correlation coefficient (ICC), Bland-Altman plots, and Cohen's Kappa analysis were performed.

RESULTS

The cohort (n = 233) mean age was 66.2 ± 12.8 years, and 74.2% of patients were male. Inter-rater reliability was excellent (ICC > 0.990, 95% confidence interval 0.975-0.996, p < 0.001). The agreement of SMI between both modalities was high according to the Bland-Altman plot (mean ΔSMI =  - 0.19 cm²/m²), and there was no substantial bias. Cohen's Kappa analysis showed an almost perfect agreement of low SMI between the two modalities (κ = 0.911, p < 0.001). The position of arms didn't affect the high agreement of (low) SMI.

CONCLUSION

Skeletal muscle mass, as measured with (low) SMI, remains constant irrespective of CT acquisition parameters (diagnostic neck CT scans versus LD neck scans of the [18F]-FDG PET-CT scan), positioning of arms, and observers. These findings contribute to the construction of a clinically useful radiological biomarker for SMI and therefore identify patients at risk for adverse clinical outcomes.

Comparison of CT derived body composition at the thoracic T4 and T12 with lumbar L3 vertebral levels and their utility in patients with rectal cancer

BACKGROUND

Computed tomography (CT) derived body composition measurements of sarcopenia are an emerging form of prognostication in many disease processes. Although the L3 vertebral level is commonly used to measure skeletal muscle mass, other studies have suggested the utilisation of other segments. This study was performed to assess the variation and reproducibility of skeletal muscle mass at vertebral levels T4, T12 and L3 in pre-operative rectal cancer patients. If thoracic measurements were equivalent to those at L3, it will allow for body composition comparisons in a larger range of cancers where lumbar CT images are not routinely measured.

RESEARCH METHODS

Patients with stage I - III rectal cancer, undergoing curative resection from 2010 - 2014, were assessed. CT based quantification of skeletal muscle was used to determine skeletal muscle cross sectional area (CSA) and skeletal muscle index (SMI). Systematic differences between the measurements at L3 with T4 and T12 vertebral levels were evaluated by percentile rank differences to assess distribution of differences and ordinary least product regression (OLP) to detect and distinguish fixed and proportional bias.

RESULTS

Eighty eligible adult patients were included. Distribution of differences between T12 SMI and L3 SMI were more marked than differences between T4 SMI and L3 SMI. There was no fix or proportional bias with T4 SMI, but proportional bias was detected with T12 SMI measurements. T4 CSA duplicate measurements had higher test-retest reliability: coefficient of repeatability was 34.10 cm² for T4 CSA vs 76.00 cm² for T12 CSA. Annotation time (minutes) with L3 as reference, the median difference was 0.85 for T4 measurements and -0.03 for T12 measurements. Thirty-seven patients (46%) had evidence of sarcopenia at the L3 vertebral level, with males exhibiting higher rates of sarcopenia. However, there was no association between sarcopenia and post-operative complications, recurrence or hospital LOS (length of stay) in patients undergoing curative resection.

CONCLUSIONS

Quantifying skeletal muscle mass at the T4 vertebral level is comparable to measures achieved at L3 in patients with rectal cancer, notwithstanding annotation time for T4 measurements are longer.

Musculoskeletal Manifestations of COVID-19: Currently Described Clinical Symptoms and Multimodality Imaging Findings

COVID-19, the clinical syndrome produced by infection with SARS-CoV-2, can result in multisystem organ dysfunction, including respiratory failure and hypercoagulability, which can lead to critical illness and death. Musculoskeletal (MSK) manifestations of COVID-19 are common but have been relatively underreported, possibly because of the severity of manifestations in other organ systems. Additionally, patients who have undergone sedation and who are critically ill are often unable to alert clinicians of their MSK symptoms. Furthermore, some therapeutic measures such as medications and vaccinations can worsen existing MSK symptoms or cause additional symptoms. Symptoms may persist or occur months after the initial infection, known as post-COVID condition or long COVID. As the global experience with COVID-19 and the vaccination effort increases, certain patterns of MSK disease involving the bones, muscles, peripheral nerves, blood vessels, and joints have emerged, many of which are likely related to a hyperinflammatory host response, prothrombotic state, or therapeutic efforts rather than direct viral toxicity. Imaging findings for various COVID-19–related MSK pathologic conditions across a variety of modalities are being recognized, which can be helpful for diagnosis, treatment guidance, and follow-up.

The online slide presentation from the RSNA Annual Meeting is available for this article.

^©RSNA, 2022

Nutritional Risk Assessment Scores Effectively Predict Mortality in Critically Ill Patients with Severe COVID-19

Background: Malnutrition predicts a worse outcome for critically ill patients. However, quick, easy-to-use nutritional risk assessment tools have not been adequately validated. Aims and Methods: The study aimed to evaluate the role of four biological nutritional risk assessment instruments (the Prognostic Nutritional Index—PNI, the Controlling Nutritional Status Score—CONUT, the Nutrition Risk in Critically Ill—NUTRIC, and the modified NUTRIC—mNUTRIC), along with CT-derived fat tissue and muscle mass measurements in predicting in-hospital mortality in a consecutive series of 90 patients hospitalized in the intensive care unit for COVID-19-associated ARDS. Results: In-hospital mortality was 46.7% (n = 42/90). Non-survivors had a significantly higher nutritional risk, as expressed by all four scores. All scores were independent predictors of mortality on the multivariate regression models. PNI had the best discriminative capabilities for mortality, with an area under the curve (AUC) of 0.77 for a cut-off value of 28.05. All scores had an AUC above 0.72. The volume of fat tissue and muscle mass were not associated with increased mortality risk. Conclusions: PNI, CONUT, NUTRIC, and mNUTRIC are valuable nutritional risk assessment tools that can accurately predict mortality in critically ill patients with COVID-19-associated ARDS.

Measurement of Sarcopenia in Head and Neck Cancer Patients and Its Association With Frailty

In head and neck cancer (HNC) there is a need for more personalized treatment based on risk assessment for treatment related adverse events (i.e. toxicities and complications), expected survival and quality of life. Sarcopenia, defined as a condition characterized by loss of skeletal muscle mass and function, can predict adverse outcomes in HNC patients. A review of the literature on the measurement of sarcopenia in head and neck cancer patients and its association with frailty was performed. Skeletal muscle mass (SMM) measurement only is often used to determine if sarcopenia is present or not. SMM is most often assessed by measuring skeletal muscle cross-sectional area on CT or MRI at the level of the third lumbar vertebra. As abdominal scans are not always available in HNC patients, measurement of SMM at the third cervical vertebra has been developed and is frequently used. Frailty is often defined as an age-related cumulative decline across multiple physiologic systems, with impaired homeostatic reserve and a reduced capacity of the organism to withstand stress, leading to increased risk of adverse health outcomes. There is no international standard measure of frailty and there are multiple measures of frailty. Both sarcopenia and frailty can predict adverse outcomes and can be used to identify vulnerable patients, select treatment options, adjust treatments, improve patient counselling, improve preoperative nutritional status and anticipate early on complications, length of hospital stay and discharge. Depending on the definitions used for sarcopenia and frailty, there is more or less overlap between both conditions. However, it has yet to be determined if sarcopenia and frailty can be used interchangeably or that they have additional value and should be used in combination to optimize individualized treatment in HNC patients.