Img-06. Imaging-Based, Temporalis Muscle Thickness as a Biomarker in Children With Gliomas

BACKGROUND Sarcopenia, or lean muscle loss, causes morbidity and early mortality in pediatric cancer patients and survivors. Sarcopenic patients who are also obese have a particularly morbid metabolic condition that cannot be identified by body mass index (BMI) alone. Temporalis muscle thickness (TMT) on T1-weighted MRI provides a direct assessment of lean muscle mass. In this study, we determined how TMT was associated with nutritional and survival outcomes in children with gliomas using an automated deep-learning pipeline that calculates TMT on MRI and provides age-and sex-specific TMT percentiles (iTMT). METHODS We analyzed a cohort of 343 patients and 1,673 scans (244 low-grade gliomas(LGG) and 99 high-grade gliomas (HGG)) diagnosed between 2000-2023 at Boston Children’s Hospital/Dana-Farber Cancer Institute, who had linked longitudinal MRI and clinical data available. We calculated and compared age-adjusted iTMT, BMI, weight percentiles, and serum albumin. Sarcopenic obesity in glioma survivors was defined as sarcopenic iTMT (<5th %tile) and obese BMI (>95th %tile). RESULTS iTMT was significantly correlated with BMI (N=1,574 scans, Spearman r=0.34, p=4e-45) and weight (N=1,574 scans, r=0.21, p=1e-17), but not serum albumin (N=84 scans, r=-0.04, p=0.66) at any given time point. Of all patients, 113(36.4%) had sarcopenic obesity during at least one time point. For HGG patients, those with less than the median survival time (550 days) had significantly lower baseline iTMT (median: 6th %tile vs. 33rd %tile, p=0.01). For LGG patients, symptoms of malnutrition at diagnosis were associated with a trend toward lower iTMT (N=244, 19th %tile vs.28th %tile, p=0.07). CONCLUSION Our study demonstrates that iTMT is an independent biomarker for malnutrition and survival for pediatric gliomas and can identify patients with sarcopenic obesity. iTMT assessment on routine clinical MRI could be a practical way to monitor muscle status and guide supportive interventions in children with brain tumors.