Temporalis muscle morphomics: the psoas of the craniofacial skeleton

High correlation of temporal muscle thickness with lumbar skeletal muscle cross-sectional area in patients with brain metastases

Objectives

This study aimed to assess the correlation of temporal muscle thickness (TMT), measured on routine cranial magnetic resonance (MR) images, with lumbar skeletal muscles obtained on computed tomography (CT) images in brain metastasis patients to establish a new parameter estimating skeletal muscle mass on brain MR images.

Methods

We retrospectively analyzed the cross-sectional area (CSA) of skeletal muscles at the level of the third lumbar vertebra on computed tomography scans and correlated these values with TMT on MR images of the brain in two independent cohorts of 93 lung cancer and 61 melanoma patients (overall: 154 patients) with brain metastases.

Results

Pearson correlation revealed a strong association between mean TMT and CSA in lung cancer and melanoma patients with brain metastases (0.733; p<0.001). The two study cohorts did not differ significantly in patient characteristics, including age (p = 0.661), weight (p = 0.787), and height (p = 0.123). However, TMT and CSA measures differed significantly between male and female patients in both lung cancer and melanoma patients with brain metastases (p<0.001).

Conclusion

Our data indicate that TMT, measured on routine cranial MR images, is a useful surrogate parameter for the estimation of skeletal muscle mass in patients with brain metastases. Thus, TMT may be useful for prognostic assessment, treatment considerations, and stratification or a selection factor for clinical trials in patients with brain metastases. Further studies are needed to assess the association between TMT and clinical frailty parameters, and the usefulness of TMT in patients with primary brain tumors.

Computed Tomography Evidence of Psoas Muscle Atrophy Without Concomitant Tendon Wasting in Early Sepsis

BACKGROUND

Morphomic studies have demonstrated a correlation between sarcopenia and clinical outcomes in septic patients. However, tendon morphomics has not yet been studied in this context. The purpose of the present study was to evaluate tendon morphology in septic patients through analytic morphomics. We hypothesized that morphomic analyses would reveal concomitant muscle and tendon wasting in sepsis patients. The results of this study may help to implement different rehabilitation modalities for critically ill patients.

MATERIALS AND METHODS

The volume and fat content of bilateral psoas muscles and tendons were measured on abdominal computed tomography scans of 25 ICU septic and 25 control trauma patients admitted to the University of Michigan between 2011 and 2012. Univariate and multivariate analyses were performed to determine the relationship between psoas muscle and tendon morphometric data, and the association with clinical variables such as smoking and comorbidities.

RESULTS

Average psoas muscle volume was 12.21 ± 5.6 cm³ for control patients and 9.318 ± 3.3 cm³ in septic patients (P = 0.0023). The average psoas muscle/fat ratio for septic patients was 0.0288 ± 0.071 cm³, compared with 0.0107 ± 0.008 cm³ in the control group (P = 0.075). Average tendon volume in the septic population (0.508 ± 0.191 cm³) was not different than the control cohort (0.493 ± 0.182 cm³) (P = 0.692).

CONCLUSIONS

Our results demonstrate significantly smaller psoas muscle volume in septic patients than in age-, gender-, and BMI-matched trauma patients but no demonstrable change in tendon morphology between patient groups. These findings begin to define the boundaries of clinical application within the field of morphomics.

Temporal muscle thickness is an independent prognostic marker in melanoma patients with newly diagnosed brain metastases

Objectives

The purpose of this study was to evaluate the prognostic relevance of temporal muscle thickness (TMT) in melanoma patients with newly diagnosed brain metastases.

Methods

TMT was retrospectively assessed in 146 melanoma patients with newly diagnosed brain metastases on cranial magnetic resonance images. Chart review was used to retrieve clinical parameters, including disease-specific graded prognostic assessment (DS-GPA) and survival times.

Results

Patients with a TMT > median showed a statistically significant increase in survival time (13 months) compared to patients with a TMT < median (5 months; p < 0.001; log rank test). A Cox regression model revealed that the risk of death was increased by 27.9% with every millimeter reduction in TMT. In the multivariate analysis, TMT (HR 0.724; 95% 0.642–0.816; < 0.001) and DS-GPA (HR 1.214; 95% CI 1.023–1.439; p = 0.026) showed a statistically significant correlation with overall survival.

Conclusion

TMT is an independent predictor of survival in melanoma patients with brain metastases. This parameter may aid in patient selection for clinical trials or to the choice of different treatment options based on the determination of frail patient populations.

Can Sarcopenia Quantified by Ultrasound of the Rectus Femoris Muscle Predict Adverse Outcome of Surgical Intensive Care Unit Patients as well as Frailty? A Prospective, Observational Cohort Study

OBJECTIVE

To compare sarcopenia and frailty for outcome prediction in surgical intensive care unit (SICU) patients.

BACKGROUND

Frailty has been associated with adverse outcomes and describes a status of muscle weakness and decreased physiological reserve leading to increased vulnerability to stressors. However, frailty assessment depends on patient cooperation. Sarcopenia can be quantified by ultrasound and the predictive value of sarcopenia at SICU admission for adverse outcome has not been defined.

METHODS

We conducted a prospective, observational study of SICU patients. Sarcopenia was diagnosed by ultrasound measurement of rectus femoris cross-sectional area. Frailty was diagnosed by the Frailty Index Questionnaire based on 50 variables. Relationship between variables and outcomes was assessed by multivariable regression analysis NCT02270502.

RESULTS

Sarcopenia and frailty were quantified in 102 patients and observed in 43.1% and 38.2%, respectively. Sarcopenia predicted adverse discharge disposition (discharge to nursing facility or in-hospital mortality, odds ratio 7.49; 95% confidence interval 1.47-38.24; P = 0.015) independent of important clinical covariates, as did frailty (odds ratio 8.01; 95% confidence interval 1.82-35.27; P = 0.006); predictive ability did not differ between sarcopenia and frailty prediction model, reflected by χ values of 21.74 versus 23.44, respectively, and a net reclassification improvement (NRI) of -0.02 (P = 0.87). Sarcopenia and frailty predicted hospital length of stay and the frailty model had a moderately better predictive accuracy for this outcome.

CONCLUSIONS

Bedside diagnosis of sarcopenia by ultrasound predicts adverse discharge disposition in SICU patients equally well as frailty. Sarcopenia assessed by ultrasound may be utilized as rapid beside modality for risk stratification of critically ill patients.

Personalized medicine: Enhancing our understanding of pediatric growth with analytic morphomics

BACKGROUND/PURPOSE

Analytic morphomics is being used to identify 3-D biologic measures with superior clinical utility and risk stratification over traditional factors such as age, height, and weight. The purpose of this study is to define age and gender specific Pediatric Reference Analytic Morphomics Population (PRAMP™) growth charts.

METHODS

This retrospective study population contains 2591 individual CT scans of a normative reference population of males and females (1-20years old). Growth curves were constructed at the 5th, 25th, 50th, 75th, and 95th quantiles for morphomic variables, including psoas muscle area, trabecular bone density, and visceral fat area by age and gender.

RESULTS

Total psoas muscle area increases over time until late adolescence. Trabecular bone density remains stable until adolescence, decreases during adolescence, and increases in young adulthood. Visceral fat area increases over time with greater variation between the 5th and 95th percentile with increasing age.

CONCLUSIONS

The PRAMP™ data have been used to construct age- and sex-specific reference growth curves. This may be used to better define "abnormal" in efforts to create unique risk-categorization algorithms specific to particular clinical and global health investigations.

LEVEL OF EVIDENCE

Level II.

Survival prediction using temporal muscle thickness measurements on cranial magnetic resonance images in patients with newly diagnosed brain metastases

Objectives

To evaluate the prognostic relevance of temporal muscle thickness (TMT) in brain metastasis patients.

Methods

We retrospectively analysed TMT on magnetic resonance (MR) images at diagnosis of brain metastasis in two independent cohorts of 188 breast cancer (BC) and 247 non-small cell lung cancer (NSCLC) patients (overall: 435 patients).

Results

Survival analysis using a Cox regression model showed a reduced risk of death by 19% with every additional millimetre of baseline TMT in the BC cohort and by 24% in the NSCLC cohort. Multivariate analysis included TMT and diagnosis-specific graded prognostic assessment (DS-GPA) as covariates in the BC cohort (TMT: HR 0.791/CI [0.703–0.889]/p < 0.001; DS-GPA: HR 1.433/CI [1.160–1.771]/p = 0.001), and TMT, gender and DS-GPA in the NSCLC cohort (TMT: HR 0.710/CI [0.646–0.780]/p < 0.001; gender: HR 0.516/CI [0.387–0.687]/p < 0.001; DS-GPA: HR 1.205/CI [1.018–1.426]/p = 0.030).

Conclusion

TMT is easily and reproducibly assessable on routine MR images and is an independent predictor of survival in patients with newly diagnosed brain metastasis from BC and NSCLC. TMT may help to better define frail patient populations and thus facilitate patient selection for therapeutic measures or clinical trials. Further prospective studies are needed to correlate TMT with other clinical frailty parameters of patients.

Key Points

• TMT has an independent prognostic relevance in brain metastasis patients.

• It is an easily and reproducibly parameter assessable on routine cranial MRI.

• This parameter may aid in patient selection and stratification in clinical trials.

• TMT may serve as surrogate marker for sarcopenia.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4707-6) contains supplementary material, which is available to authorized users.

Early Development of the Mouse Morphome

INTRODUCTION

Analytical morphomics focuses on extracting objective and quantifiable data from clinical computed tomography (CT) scans to measure patients' frailty. Studies are currently retrospective in nature; therefore, it would be beneficial to develop animal models for well-controlled, prospective studies. The aim of this study is to develop an in vivo microCT protocol for the longitudinal acquisition of whole-body images suitable for morphomic analyses of bone.

METHODS

The authors performed phantom studies on 2 microCT systems (Inveon and CT120) to study tissue radiodensity and further characterize system performance for collecting animal data. The authors also describe their design of a phantom-immobilization device using phantoms and an ovariectomized (OVX) mouse.

RESULTS

The authors discovered increased consistency along the z-axis for scans acquired on the Inveon compared with CT120, and calibration by individual slice reduces variability. Objects in the field of view had more impact on measurement acquired using the CT120 compared with the Inveon. The authors also found that using the middle 80% of slices for data analysis further decreased variability, on both systems. Moreover, bone-mineral-density calibration using the QCT Pro Mini phantom improved bone-mineral-density estimates across energy spectra, which helped confirm our technique. Comparison of weekly body weights and terminal uterine mass between sham and OVX groups validated our model.

DISCUSSION

The authors present a refined microCT protocol to collect reliable and objective data. This data will be used to establish a platform for research animal morphomics that can be used to test hypotheses developed from clinical human morphomics.

Morphomic analysis as an aid for preoperative risk stratification in patients undergoing major head and neck cancer surgery

BACKGROUND

Patients undergoing major head and neck cancer surgery (MHNCS) may develop significant postoperative complications. To minimize the risk of complications, clinicians often assess multiple measures of preoperative health in terms of medical comorbidities. One emerging method to decrease surgical complications is preoperative assessment of patient frailty measured by specific tissue characteristics. We hypothesize that morphomic characteristics of the temporalis region serve as predictive markers for the development of complications after MHNCS.

METHODS

We performed a retrospective review of 69 patients with available computed tomography (CT) imaging who underwent MHNCS from 2006-2012. To measure temporalis region characteristics, we used morphomic analysis of available preoperative CT scans to map out the region. All available CT scans had been performed as part of the patient's routine work-up and were not ordered for morphomic analysis. We describe the correlation among temporalis fat pad volume (TFPV), mean zygomatic arch thickness, and incidence of postoperative complications.

RESULTS

We noted significant difference in the zygomatic bone thickness and TFPV between patients who had medical complications, surgical complications, or total major complications and those who did not. Furthermore, by use of binary logistic regression, our data suggest decreased TFPV and zygomatic arch thickness are stronger predictors of developing postoperative complications than previously studies preoperative characteristics.

CONCLUSIONS

We describe morphomic analysis of the temporalis region in patients undergoing MHNCS to identify patients at risk for complications. Regional anatomic morphology may serve as a marker to objectively determine a patient's overall health. Use of the temporalis region is appropriate in patients undergoing MHNCS because of the availability of preoperative scans as part of routine work up for head and/or neck cancer.