Diffusion Tensor Imaging of Skeletal Muscle Contraction Using Oscillating Gradient Spin Echo

Abstract

Diffusion tensor imaging (DTI) measures water diffusion in skeletal muscle tissue and allows for muscle assessment in a broad range of neuromuscular diseases. However, current DTI measurements, typically performed using pulsed gradient spin echo (PGSE) diffusion encoding, are limited to the assessment of non-contracted musculature, therefore providing limited insight into muscle contraction mechanisms and contraction abnormalities. In this study, we propose the use of an oscillating gradient spin echo (OGSE) diffusion encoding strategy for DTI measurements to mitigate the effect of signal voids in contracted muscle and to obtain reliable diffusivity values. Two OGSE sequences with encoding frequencies of 25 and 50 Hz were tested in the lower leg of five healthy volunteers with relaxed musculature and during active dorsiflexion and plantarflexion, and compared with a conventional PGSE approach. A significant reduction of areas of signal voids using OGSE compared with PGSE was observed in the tibialis anterior for the scans obtained in active dorsiflexion and in the soleus during active plantarflexion. The use of PGSE sequences led to unrealistically elevated axial diffusivity values in the tibialis anterior during dorsiflexion and in the soleus during plantarflexion, while the corresponding values obtained using the OGSE sequences were significantly reduced. Similar findings were seen for radial diffusivity, with significantly higher diffusivity measured in plantarflexion in the soleus muscle using the PGSE sequence. Our preliminary results indicate that DTI with OGSE diffusion encoding is feasible in human musculature and allows to quantitatively assess diffusion properties in actively contracting skeletal muscle. OGSE holds great potential to assess microstructural changes occurring in the skeletal muscle during contraction, and for non-invasive assessment of contraction abnormalities in patients with muscle diseases.

Inter-vendor and inter-observer reliability of diffusion tensor imaging in the musculoskeletal system: a multiscanner MR study

“…Muscle contraction induces muscle fibre shortening and increases cross-sectional area (CSA), producing higher MD and lower FA values. Mazzoli et al [31] performed MRI examinations of the lower leg on five volunteers during muscle contraction and found lower FA values of anterior tibialis in dorsiflexion compared with plantarflexion contraction and no contraction. The assessment of DTI values during muscle contraction is complex due to the length of current MRI sequences, which do not allow for constant, homogeneous fibre contraction.…”

A registration strategy to characterize DTI-observed changes in skeletal muscle architecture due to passive shortening

“…With this approach, it may be possible to answer previously unrealizable questions in the study of muscle structure-function relationships. To realize such possibilities, DTI data would ideally be acquired during a muscle contraction; but this is challenging due to long scan times required for muscle DTI, the potential for motion artefacts, and signal voids that may occur when diffusion-weighted images are acquired during contraction (31)(32)(33). This challenge is amplified by the fact that whole muscle DTI is required to provide a complete understanding of the architectural changes during contraction, which typically requires multi-stack acquisitions thereby increasing the total acquisition time in direct proportion to the number of stacks acquired.…”

Impact of Deep Learning Denoising Algorithm on Diffusion Tensor Imaging of the Growth Plate on Different Spatial Resolutions

“…Ample studies have used DL to optimize DTI in the central nervous system, from basic denoising to using denoising algorithms to minimize the diffusion weighted data requirements, and even to asses sensitivity and specificity of the technique for classification of white matter disorders [ 14 , 15 , 16 , 17 , 18 ]. However, only a few studies have investigated the effects of varying acquisition parameters on DTI metrics in the orthopedic field, which were predominantly performed on adults or animal models, primarily focusing on adult muscle fibers or articular structures in rat knees [ 19 , 20 , 21 , 22 , 23 , 24 ]. These studies highlighted the sensitivity of knee connective tissues, specifically ligaments, to changes in spatial resolution [ 24 ].…”