Added Value of Morphological and Functional Magnetic Resonance Neurography in Assessment of Carpal Tunnel Syndrome in Correlation with Nerve Conduction Studies

Abstract

Background: To study the value of morphological and functional MRI criteria in diagnosis of carpal tunnel syndrome (CTS) and determine cut-off values between normal individuals and CTS patients. Patients and methods: Forty wrists were examined in 24 patients with CTS diagnosis confirmed by nerve conduction studies (NCS) and in 10 healthy subjects. Cross-sectional area (CSA), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured at three levels as well as signal intensity ratio (SIR), flattening ratio (FR) and retinacular bowing ratio. Comparison between the two groups was done. Results: CSA is increased in CTS patients compared to healthy controls. The cut off value for CSA at pisiform bone was little more sensitive than maximum CSA. SIR & FR showed no significant difference between CTS patients and control groups. RBR is increased in CTS patients. FA is decreased in CTS patients. A significant positive correlation was found between maximum CSA & highest ADC, and the findings of NCS. A significant negative correlation was found between lowest FA and the findings of NCS. Conclusions: CSA, RBR, FA & ADC are highly significant predictors of carpal tunnel syndrome. FR and SIR are not reliable for diagnosis of carpal tunnel syndrome. Maximum CSA, lowest FA & highest ADC can be used for grading of CTS severity.