Determination of three‐dimensional muscle architectures: validation of the DTI‐based fiber tractography method by manual digitization

Abstract

In the last decade, diffusion tensor imaging (DTI) has been used increasingly to investigate three-dimensional (3D) muscle architectures. So far there is no study that has proved the validity of this method to determine fascicle lengths and pennation angles within a whole muscle. To verify the DTI method, fascicle lengths of m. soleus as well as their pennation angles have been measured using two different methods. First, the 3D muscle architecture was analyzed in vivo applying the DTI method with subsequent deterministic fiber tractography. In a second step, the muscle architecture of the same muscle was analyzed using a standard manual digitization system (MicroScribe MLX). Comparing both methods, we found differences for the median pennation angles (P < 0.001) but not for the median fascicle lengths (P = 0.216). Despite the statistical results, we conclude that the DTI method is appropriate to determine the global fiber orientation. The difference in median pennation angles determined with both methods is only about 1.2°(median pennation angle of MicroScribe: 9.7°; DTI: 8.5°) and probably has no practical relevance for muscle simulation studies. Determining fascicle lengths requires additional restriction and further development of the DTI method.

Force reduction induced by unidirectional transversal muscle loading is independent of local pressure

“…Therefore, it seems important to examine the intermuscular pressure in muscle groups and threedimensional muscle deformations during contraction (Böl et al, 2015Röhrle et al, 2012;Rupp et al, 2015) in more detail. With such studies, questions related to evolution of sometimescomplex muscle architecture (e.g., distributions of varying fiber lengths and pennation angles or inner tendon sheets (Gorb and Fischer, 2000;Hiepe et al, 2014;Schenk et al, 2013;Siebert et al, 2015;Stark and Schilling, 2010)) could be addressed. However, it is also possible that transversal pressure is not a bad thing per se.…”

Correlation of diffusion tensor imaging parameters and Gleason scores of prostate cancer

“…This technique is widely used for imaging in the central nervous system and skeletal muscle system (15,16); however, the use of DTI for the diagnosis, classification and evaluation of PCa remains unknown (17)(18)(19).…”

A computational approach to calculate personalized pennation angle based on MRI: effect on motion analysis

“…Previous studies reported the pennation angle based on 2D and 3D ultrasound images [24,44], cadavers measurements [46], and DTI [39]. However, the 2D ultrasound uses only 2D information, restricting the access to the volumetric geometrical data, and is very sensitive to the plane alignment, while DTI acquisitions are still tedious to perform accurately for musculoskeletal applications due to low spatial resolution and low signal-to-noise ratio.…”

“…Recently, more complex techniques such as diffusion tensor imaging (DTI) [39] or 3D ultrasound devices [35] were used to quantify the PA. However, these modalities give noisy data and require additional post-processing steps, which are not always robust.…”