Diffusion tensor imaging in the musculoskeletal and peripheral nerve systems: from experimental to clinical applications

Abstract

Magnetic resonance imaging (MRI) is a well-established imaging modality which is used in all districts of the musculoskeletal and peripheral nerve systems. More recently, initial studies have applied multiparametric MRI to evaluate quantitatively different aspects of musculoskeletal and peripheral nerve diseases, thus providing not only images but also numbers and clinical data. Besides ¹H and ³¹P magnetic resonance spectroscopy, diffusion-weighted imaging (DWI) and blood oxygenation level-dependent imaging, diffusion tensor imaging (DTI) is a relatively new MRI-based technique relying on principles of DWI, which has traditionally been used mainly for evaluating the central nervous system to track fibre course. In the musculoskeletal and peripheral nerve systems, DTI has been mostly used in experimental settings, with still few indications in clinical practice. In this review, we describe the potential use of DTI to evaluate different musculoskeletal and peripheral nerve conditions, emphasising the translational aspects of this technique from the experimental to the clinical setting.

Keywords: Diffusion tensor imaging; Magnetic resonance imaging; Muscle; Tendon; Tractography.

Fig. 1

a Axial fat-saturated proton-density image of the middle third of the leg of a 29-year-old male patient who sustained a grade 2c tear of the medial gastrocnemius muscle (asterisks). T tibia, arrows normal tibialis anterior muscle. b Tractography of the tibialis anterior muscle, showing normally oriented and arranged fibres. c Regions of interest are placed on the torn muscle (1) and healthy muscle tissue (2). d Quantitative analysis shows different values in the torn muscle compared to healthy tissue, in particular a lower FA (0.17) compared to that of healthy fibres (0.27)

Fig. 2

Magnetic resonance of the thigh performed on a 42-year-old male aptient with mild limb-girdle muscular dystrophy. a Morphological appearance on axial T1-weighted image (arrows). F femur. b The corresponding tractography image shows fibres which are decreased in number, length and organisation due to partial fatty replacement. This appearance can be particularly appreciated if compared to Fig. 1b, which shows a normal participant

Fig. 3

Magnetic resonance of the knee performed on a 24-year-old male patient two months after soccer injury. a Sagittal T1-weighted image shows that the anterior cruciate ligament is remarkably inhomogeneous due a partial tear (arrows). F femur, T tibia. b The corresponding tractography image shows that fibres are partially interrupted and architecture is disrupted (arrows)

Fig. 4

Magnetic resonance of the lumbar spine performed on a of 31-year-old man. a Sagittal T2-weighted image shows protrusion of a thinned and dehydrated intervertebral disc (Pfirrmann IV, arrows) at L5-S1. b Tractograpy shows irregular, disordered and thin fibres