Abstract Details

Title Multiparametric Quantitative MRI of Peripheral Nerves to Differentiate Axonal from Demyelinating Neuropathies

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P11 - Poster Session 11 (11:45 AM-12:45 PM)

Poster/Presentation
Number 10-002

Objective To develop a multiparametric quantitative MRI (qMRI) method to track pathological changes of peripheral nerves in patients with peripheral neuropathies.

Background Irrespective of the causes or types of polyneuropathies, peripheral nerves are mainly afflicted by two kinds of pathologies – axonal loss and demyelination. It is critical to differentiate the two as treatments are different for the two conditions. While nerve conduction studies (NCS) have been used to differentiate the two pathologies in the distal nerves, there are no tools to probe the pathologies in the proximal peripheral nerves. This is particularly needed when distal nerves become non-responsive in NCS.

Design/Methods We have developed a multiparametric qMRI method that quantifies the sciatic and tibial nerves with 10 parameters that are sensitive to different aspects of myelin and axonal pathologies: magnetization transfer ratio (MTR), magnetization transfer saturation index (MTsat), longitudinal relaxation time (T1), proton density (PD), effective transverse relaxation time (T2*), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and nerve fascicular volume (fVol). In this pilot study, we studied 4 patients with Charcot-Marie-Tooth type-1A (CMT1A), 2 patients with CMT type-2S (CMT2S), and 17 healthy controls.

Results Compared with healthy controls, patients with CMT2S (reportedly as axonal type) had comparable MTR, MTsat, T1, PD and fVol, but reduced T2*. While patients with CMT1A (dysmyelinating type) had reduced MTR and MTsat, increased fVol, T1 and PD, and comparable T2*. All the 6 patients shared changes of reduced FA which was driven by a reduced AD and an increased RD.

Conclusions The data show different qMRI patterns between axonal and demyelinating neuropathies. The differential changes will be further verified in a larger cohort of patients with peripheral neuropathies.

Authors/Disclosures
Yongsheng Chen, PhD (Wayne State University) PRESENTER	Dr. Chen has nothing to disclose.
Jacob D. Baraz	Mr. Baraz has nothing to disclose.
	No disclosure on file
	No disclosure on file
Xue Yang, MD, PhD (Wayne State University/Detroit Medical Center)	Dr. Yang has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Jun Li, MD, PhD, FAAN (Harris Methodist Hospital)	The institution of Dr. Li has received personal compensation in the range of $500-$4,999 for serving as a Consultant for FDA. The institution of Dr. Li has received research support from NIH. Dr. Li has a non-compensated relationship as a Associate Editor of ACTN journal with ANA that is relevant to AAN interests or activities.

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