Standard values for temporal muscle thickness in the Japanese population who undergo brain check-up by magnetic resonance imaging

Background: Skeletal muscle mass is an important factor for various diseases’ outcomes. The psoas muscle cross-sectional area on the abdominal computed tomography (CT), gait speed, and handgrip strength is used to measure it. However, it is difficult to measure the neurological patients’ muscle mass or function because (1) we do not perform abdominal CT. (2) Such patients have impaired consciousness, gait disturbance, paresis, and need of rest. Temporal muscle thickness (TMT) on magnetic resonance imaging (MRI) is now attractive for skeletal muscle volume indicator, but the reference values are not established. We herein investigated the standard value of the Japanese TMT using the brain check-up database by MRI. Methods: We retrospectively investigated 360 Japanese individuals from two institutions between 2017 and 2019. We measured TMT on the T1-weighted images in the previously reported way. The associations between TMT and other variables were analyzed. Results: TMT of 214 women and 146 men, ranging from 35 to 84 years old, was investigated. TMT ranged from 3.69 to 16.90 mm. Mean TMT values were significantly higher in men compared to women except for the over 70-year-old cohort. TMT was correlated to weight and body mass index in both sexes. Conclusion: This is the first retrospective study on the standard TMT values from the Japanese brain check-up database. Our results were just reference values, but these would be useful for further investigation in other neurosurgical and neurological diseases regarding muscle volume or sarcopenia.

COT-12 CLINICAL MANAGEMENT AND TIMING OF SURGICAL TREATMENT FOR ASYMPTOMATIC GLIOMA

BACKGROUND In Japan, there are many cases where intracranial diseases are found accidentally due to the widespread use of MRI and brain check-up. Unruptured cerebral aneurysms and asymptomatic cerebral infarctions are often diagnosed, but asymptomatic glioma is rarely diagnosed. We analyzed the asymptomatic gliomas retrospectively among grade 2 or higher gliomas that had undergone diagnostic imaging or surgical treatment in our institution. MATERIAL AND METHODS Of 166 adults with grade 2 or higher grade glioma treated in our institution between 2007 and 2018, 15 cases were asymptomatic. Twelve cases were males and 3 were females, with an average age of 55.1 years (34–79 years). There were 7 cases found in brain check-up, 6 cases in the follow-up of other intracranial diseases, and 2 cases in migraine. Twelve patients, except 3 patients, have undergone surgical treatment, and the average time from an initial imaging to surgical treatment was 51.1 weeks (2 to 329 weeks). Eight patients were treated after radiological follow-up and 4 cases are treated within 2 months after the tumor was discovered. The pathological diagnosis was grade 2: 5 cases, grade 3: 2 cases, and grade 4: 5 cases. Three patients without surgical treatment were diagnosed as grade 2 on MRI. Six patients died during follow-up. The median survival time from the first surgical treatment for grade 3 and 4 glioma was 17 months. CONCLUSION Incidence of asymptomatic glioma is very rare. Even for asymptomatic gliomas, the prognosis is not so good due to malignant transformation and disease progression. It is important to explain the natural course of disease and treatment strategy accurately.