» Articles » PMID: 38010923

Improved Fascicle Length Estimates From Ultrasound Using a U-net-LSTM Framework

Overview
Authors
Affiliations
Soon will be listed here.
Abstract

Brightness-mode (B-mode) ultrasound has been used to measure in vivo muscle dynamics for assistive devices. Estimation of fascicle length from B-mode images has now transitioned from time-consuming manual processes to automatic methods, but these methods fail to reach pixel-wise accuracy across extended locomotion. In this work, we aim to address this challenge by combining a U-net architecture with proven segmentation abilities with an LSTM component that takes advantage of temporal information to improve validation accuracy in the prediction of fascicle lengths. Using 64,849 ultrasound frames of the medial gastrocnemius, we semi-manually generated ground-truth for training the proposed U-net-LSTM. Compared with a traditional U-net and a CNNLSTM configuration, the validation accuracy, mean square error (MSE), and mean absolute error (MAE) of the proposed U-net-LSTM show better performance (91.4%, MSE =0.1± 0.03 mm, MAE =0.2± 0.05 mm). The proposed framework could be used for real-time, closed-loop wearable control during real-world locomotion.

References
1.
Zhao H, Zhang L . Automatic tracking of muscle fascicles in ultrasound images using localized Radon transform. IEEE Trans Biomed Eng. 2011; 58(7):2094-101. DOI: 10.1109/TBME.2011.2144593. View

2.
Drazan J, Hullfish T, Baxter J . An automatic fascicle tracking algorithm quantifying gastrocnemius architecture during maximal effort contractions. PeerJ. 2019; 7:e7120. PMC: 6611451. DOI: 10.7717/peerj.7120. View

3.
Zhou Y, Zheng Y . Estimation of muscle fiber orientation in ultrasound images using revoting hough transform (RVHT). Ultrasound Med Biol. 2008; 34(9):1474-81. DOI: 10.1016/j.ultrasmedbio.2008.02.009. View

4.
Lai A, Lichtwark G, Schache A, Lin Y, Brown N, Pandy M . In vivo behavior of the human soleus muscle with increasing walking and running speeds. J Appl Physiol (1985). 2015; 118(10):1266-75. DOI: 10.1152/japplphysiol.00128.2015. View

5.
Bohm S, Mersmann F, Santuz A, Arampatzis A . The force-length-velocity potential of the human soleus muscle is related to the energetic cost of running. Proc Biol Sci. 2019; 286(1917):20192560. PMC: 6939913. DOI: 10.1098/rspb.2019.2560. View