AUTHOR=Chu Xujun , Du Kang , Tang Yuwei , Zhao Xutong , Yu Meng , Zheng Yiming , Deng Jianwen , Lv He , Zhang Wei , Wang Zhaoxia , Yuan Yun , Meng Lingchao 

TITLE=Skeletal Muscle Involvement Pattern of Hereditary Transthyretin Amyloidosis: A Study Based on Muscle MRI

JOURNAL=Frontiers in Neurology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.851190

DOI=10.3389/fneur.2022.851190

ISSN=1664-2295

ABSTRACT=Objects: This study was intended to explore the characteristics of muscle magnetic resonance imaging (MRI) of patients with hereditary transthyretin amyloidosis (ATTRv amyloidosis) prospectively.
Methods: The clinical data on 20 patients with ATTRv amyloidosis at our hospital between July 2020 and August 2021 was analyzed. MRI of lower limbs including calf muscles was performed in all these 20 patients and MRI of thigh muscles was performed in sixteen of them.
Results: The mean age of the 20 ATTRv amyloidosis patients was 44.2 years (ranging from 26 to 60) whose mean duration of weakness was 23.3±23.0 (ranging from 0 to 84 months) months. All the patients presented with polyneuropathy, and eighteen of them with weakness of lower limbs. Muscle involvement was selective in these patients with ATTRv amyloidosis. The posterior group of muscles was heavily fatty, and the soleus muscle was the most heavily involved. The proportion of fatty infiltration scores at the calf level was higher than at the thigh level with paired comparison for most patients. Three of these patients (patient 5, 8, 17) had more severe fatty infiltration of muscles at the thigh level. The fatty infiltration of posterior compartments at the calf level was highly consistent with neuropathy impairment scores of lower limbs (weakness), strength of ankle plantar flexion muscles and amplitude of compound muscle action potentials of the common peroneal nerve.
Conclusions: It was found that the pattern of muscle fatty infiltration was consistent with a distal -to- proximal gradient on the whole, and that proximal involvements in MRI of lower limbs in some patients could also be observed. Selective fatty infiltration of muscles of posterior compartments and fatty infiltration of the soleus muscle might be typical of ATTRv amyloidosis.