Diffusion tensor imaging and tractography of the median nerve in carpal tunnel syndrome: preliminary results

Abstract

The purpose was to demonstrate the feasibility of in vivo diffusion tensor imaging (DTI) and tractography of the human median nerve with a 1.5-T MR scanner and to assess potential differences in diffusion between healthy volunteers and patients suffering from carpal tunnel syndrome. The median nerve was examined in 13 patients and 13 healthy volunteers with MR DTI and tractography using a 1.5-T MRI scanner with a dedicated wrist coil. T1-weighted images were performed for anatomical correlation. Mean fractional anisotropy (FA) and mean apparent diffusion coefficient (ADC) values were quantified in the median nerve on tractography images. In all subjects, the nerve orientation and course could be detected with tractography. Mean FA values were significantly lower in patients (p=0.03). However, no statistically significant differences were found for mean ADC values. In vivo assessment of the median nerve in the carpal tunnel using DTI with tractography on a 1.5-T MRI scanner is possible. Microstructural parameters can be easily obtained from tractography images. A significant decrease of mean FA values was found in patients suffering from chronic compression of the median nerve. Further investigations are necessary to determine if mean FA values may be correlated with the severity of nerve entrapment.

Quantitative Evaluation and Visualization of Lumbar Foraminal Nerve Root Entrapment by Using Diffusion Tensor Imaging: Preliminary Results

“…MR neurography by using DWI can clearly show lumbar nerve roots, and the mean ADC in nerve root entrapment with foraminal stenosis is higher than in intact nerve roots in approximately a 10-minute scan time by using MR imaging at 1.5 T. 20 The ADC map is limited because the tissue contrast between nerves and surrounding tissues is poor. 15 In this study, we have shown that DTI can clearly show tractograms of lumbar nerve roots and determine FA values of the nerve roots in patients and healthy volunteers in approximately a 5-minute scan time by using MR imaging at 3T.…”

“…Recently, several studies have shown that DTI is useful for the evaluation and visualization of peripheral nerves 15 and the measurement of axon regeneration in rat 16 and mouse 17 sciatic nerves, demonstrating that a decrease in mean FA values was observed in injured nerves with demyelination. [15][16][17][18] Imaging of the spinal cord is challenging because of technical limitations such as the relatively small size of the cord, susceptibility artifacts because of tissue-bone interfaces, and the motion artifacts arising from respiratory activity.…”

“…[15][16][17][18] Imaging of the spinal cord is challenging because of technical limitations such as the relatively small size of the cord, susceptibility artifacts because of tissue-bone interfaces, and the motion artifacts arising from respiratory activity. 19 Although we reported previously that DWI of lumbar nerves by using 1.5T MR imaging could visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis, 20 to date, quantitative DTI has not been applied to evaluate the pathology of lumbar nerve root entrapment.…”

Cerebral Diffusion Tensor MR Tractography in Tuberous Sclerosis Complex: Correlation with Neurologic Severity and Tract-Based Spatial Statistical Analysis

“…As a result, the major white matter tracts of each subject were reconstructed in 3 sessions: 2 yielding the PF and 1 yielding the CF. Quantitative results of the generated fibers, including the right and left PF, CF, and the summation of these tracts (MWT), were automatically obtained by the software, 26 initiated by right-clicking with the mouse on the fibers. The results include the FA, NOP, and NOF.…”

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

“…DWI has been widely used for clinical applications in evaluation of the central nervous system for the diagnosis of diseases such as acute brain stroke [14]. Recently, it has been reported that DWI is useful for the evaluation and diagnosis of lesions such as multiple sclerosis [15,16] and peripheral nerve compression disorders such as carpal tunnel syndrome [17][18][19], using diffusion values such as ADC. An increase in the mean diffusivity (ADC) values was observed in injured nerves with demyelination [15,16,19,20].…”