Diffusion tensor imaging in cubital tunnel syndrome

Abstract

Cubital tunnel syndrome (CuTS) is the 2nd most common compressive neuropathy. To improve both diagnosis and the selection of patients for surgery, there is a pressing need to develop a reliable and objective test of ulnar nerve ‘health’. Diffusion tensor imaging (DTI) characterises tissue microstructure and may identify differences in the normal ulnar from those affected by CuTS. The aim of this study was to compare the DTI metrics from the ulnar nerves of healthy (asymptomatic) adults and patients with CuTS awaiting surgery. DTI was acquired at 3.0 T using single-shot echo-planar imaging (55 axial slices, 3 mm thick, 1.5 mm2 in-plane) with 30 diffusion sensitising gradient directions, a b-value of 800 s/mm2 and 4 signal averages. The sequence was repeated with the phase-encoding direction reversed. Data were combined and corrected using the FMRIB Software Library (FSL) and reconstructed using generalized q-sampling imaging in DSI Studio. Throughout the length of the ulnar nerve, the fractional anisotropy (FA), quantitative anisotropy (QA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were extracted, then compared using mixed-effects linear regression. Thirteen healthy controls (8 males, 5 females) and 8 patients with CuTS (6 males, 2 females) completed the study. Throughout the length of the ulnar nerve, diffusion was more isotropic in patients with CuTS. Overall, patients with CuTS had a 6% lower FA than controls, with the largest difference observed proximal to the cubital tunnel (mean difference 0.087 [95% CI 0.035, 0.141]). Patients with CuTS also had a higher RD than controls, with the largest disparity observed within the forearm (mean difference 0.252 × 10–4 mm2/s [95% CI 0.085 × 10–4, 0.419 × 10–4]). There were no significant differences between patients and controls in QA, MD or AD. Throughout the length of the ulnar nerve, the fractional anisotropy and radial diffusivity in patients with CuTS are different to healthy controls. These findings suggest that DTI may provide an objective assessment of the ulnar nerve and potentially, improve the management of CuTS.

Meta-analysis of the normal diffusion tensor imaging values of the peripheral nerves in the upper limb

“…In the region of the elbow, the ulnar nerve appeared to have a 12% lower FA than the median and radial nerves (CI − 0.25, 0.00; p < 0.001, I 2 96%). The normal MD of the median 51 , 52 , radial 51 and ulnar 39 , 41 , 44 , 46 , 49 , 51 , 52 , 54 , 54 nerves in the elbow region was 1.01 × 10 –3 mm 2 /s (CI 0.68, 1.34), 0.71 × 10 –3 mm 2 /s (CI 0.64, 0.78) and 1.11 × 10 –3 mm 2 /s (CI 1.01, 1.20), respectively (eFigure S12 ). The radial nerve had lower MD than the ulnar nerve (− 0.40 × 10 –3 mm 2 /s CI − 0.76, − 0.04]; p < 0.001, I 2 93%) but was similar to the median nerve.…”

“…Around the elbow, the normal FA of the median 51 , 52 , radial 51 and ulnar 38 , 39 , 41 , 44 , 46 , 49 , 51 , 52 , 54 nerves are shown in Fig. 2 .…”

Efficacy of Nerve-Derived Hydrogels to Promote Axon Regeneration Is Influenced by the Method of Tissue Decellularization

“…The diffusion data was reconstructed and analysed in DSI Studio (13 December 2018 Build) using generalized q-sampling imaging (GQI) [ 71 ] with a diffusion sampling length ratio of 0.6. GQI is a model-free approach with outputs comparable to complex q-space methods, and produces quantitative anisotropy (QA) maps with better contrast than traditional fractional anisotropy (FA) maps when identifying peripheral nerves [ 72 ]. It produces the traditional diffusion parameters FA, mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).…”

Intraoperative electrical stimulation promotes the short-term recovery of patients with cubital tunnel syndrome after surgery

“…The main cause of cubital tunnel syndrome is the enduring, repetitive flexion of elbow that raises the pressure inside the cubital tunnel and strains the ulnar nerve, affecting the microcirculation within the nerve and causing ischemia and hypoxia resulting in nerve damage [ 4 ]. Chronic compression leads to demyelination and the distortion of axonal structures, followed by undesirable remyelination [ 5 ]. The motor symptoms include dyspraxia and weakness of the hand and the sensory symptoms include pain, hypoesthesia or anesthesia, and cutaneous dysesthesias [ 5 ].…”

“…Chronic compression leads to demyelination and the distortion of axonal structures, followed by undesirable remyelination [ 5 ]. The motor symptoms include dyspraxia and weakness of the hand and the sensory symptoms include pain, hypoesthesia or anesthesia, and cutaneous dysesthesias [ 5 ]. For patients with mild symptoms, they can heal spontaneously without surgery [ 6 ].…”