Feasibility of sagittal T2 mapping of the median nerve in patients with carpal tunnel syndrome

Abstract

Purpose: To evaluate patients with carpal tunnel syndrome (CTS) by using 3-Tesla magnetic resonance imaging (MRI) sagittal T2 mapping of the median nerve for localization of abnormal regions. Material and Methods: Nine hands of seven patients with CTS and five hands of five healthy volunteers were evaluated using sagittal T2 mapping and axial spoiled gradient-echo (SPGR) images. Three regions of interest (ROIs) at the carpal tunnel (ROI-1 to ROI-3) and one control ROI distal to the carpal tunnel (ROIC) were defined on the median nerve and T2-ratios at ROI-1 to ROI-3 relative to ROI-C were calculated. The flattening ratio (F-ratio; width/height of the median nerve) was also calculated from the axial SPGR images. Results: On sagittal T2 mapping, the medial nerve of normal volunteers showed constant T2 values at all ROIs. In the patients with CTS, there was large variation in T2 among the ROIs and the region of highest T2 value varied among the patients. T2-ratios at ROI-2 and -3 and the F-ratios along all carpal tunnel levels were significantly higher in the patients with CTS than in the normal volunteers. A significant correlation was found between terminal latency and T2-ratio at ROI-2 but not between terminal latency and F-ratio. Conclusion: Sagittal T2 mapping was feasible for the localization of abnormal T2 regions of the median nerve in patients with CTS.

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

“…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 (8–16) and often long scan times (>8 min) for acquiring high in-plane resolution (0.3 mm) ( 10 ). Nevertheless, promising findings of correlation between nerve MESE T2 and electrodiagnostic results have been observed ( 4 , 11 ), which motivate improving the spatial resolution of T2 mapping in peripheral nerve assessment.…”