T2 mapping of the median nerve in patients with carpal tunnel syndrome and healthy volunteers

Abstract

Introduction We investigated the changes in MRI T2 mapping values in subjects with carpal tunnel syndrome (CTS) compared to healthy controls. Methods We enrolled 71 patients with CTS and 26 healthy controls. Median nerve T2 values were measured at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels. These were compared between patients and controls and correlated with median nerve cross‐sectional area (CSA) and nerve conduction measurements. Results The mean T2 values at the proximal carpal tunnel levels were higher in the CTS group (56.7 ms) than in the control group (51.2 ms, P = .02) and also were higher than at the distal carpal tunnel (51.0 ms, P < .001) and forearm levels (47.6 ms, P < .001). T2 values were not significantly associated with CSA or nerve conduction measurements. Discussion T2 mapping of the carpal tunnel provides qualitative information on median nerve pathology but does not reflect CTS severity.

Feasibility of simultaneous high‐resolution anatomical and quantitative magnetic resonance imaging of sciatic nerves in patients with Charcot–Marie–Tooth type 1A (CMT1A) at 7T

“…T2 relaxation has been explored as a biomarker for estimating the breakdown of the extracellular matrix in cartilage, 18 muscle inflammation, 19 and peripheral nerves. [20][21][22] T2 relaxation in a relatively bidirectional structure such as a peripheral nerve could represent the degree of structural integrity. 23 The ability to estimate T2 in single fascicles, in combination with anatomical images acquired concurrently, presents a future direction of using fascicle size and T2 value in a complimentary manner for assessing the health of peripheral nerves and surrounding muscles.…”

“…T2 relaxation is a common measure in MR, describing how fast the signal decays due to spin–spin interaction. T2 relaxation has been explored as a biomarker for estimating the breakdown of the extracellular matrix in cartilage, 18 muscle inflammation, 19 and peripheral nerves 20–22 . T2 relaxation in a relatively bidirectional structure such as a peripheral nerve could represent the degree of structural integrity 23 .…”

Quantitative double echo steady state T2 mapping of upper extremity peripheral nerves and muscles

“…Based on a previous study involving T2 mapping in forearm nerve compression ( 5 ), it was calculated that the current study would require a sample size of 16 to achieve a power of 80% and a level of significance of 5% (two-sided) for detecting a mean T2 difference of 5.5 msec between pairs, assuming the standard deviation of the differences was 6.9 msec.…”

“…Conventional T2 mapping provides quantitative information with potentially less bias than qualitative evaluation of T2-weighted signal intensity ( 4 ). T2 mapping can quantify neuropathy-related changes in nerve ( 5 , 6 ) and has demonstrated correlation with electrodiagnostic results in muscles including those of the upper extremity ( 4 , 7 ).…”

“…While T2 values may be obtained using a number of different methods, including fast spin-echo (FSE)/turbo spin-echo (TSE) at multiple echo times (5) and T2-prepared TSE (8), the most commonly-used method for T2-mapping is the conventional multi-echo spin-echo (MESE) method. While T2 mapping using MESE has been readily applied in muscle (7,9), it is limited in nerve imaging because (i) as a 2D acquisition, MESE typically has poor slice-resolution (3-6 mm) and may not be readily reformatted in different planes for nerve evaluation, and (ii) MESE has poor scan efficiency, requiring multiple echoes (8)(9)(10)(11)(12)(13)(14)(15)(16)) and often long scan times (>8 min) for acquiring high in-plane resolution (0.3 mm) (10).…”