In vivo detection of XXXX in @entity14755 by magnetic resonance neurography.

@entity1 @entity66 @entity16 @entity4218 @entity128 @entity305 @entity14755 @entity74 @entity20117 @entity1930
UNASSIGNED: @entity20117 @entity14755 is a rare, @entity74 usually manifesting with a rapidly progressive, axonal, distally-symmetric @entity305 . The detection of @entity128 by nerve conduction studies is limited, due to preferential involvement of small-fibres in early stages. We investigated whether lower limb @entity128 can be detected, localized and quantified in vivo by high-resolution magnetic resonance neurography. We prospectively included 20 @entity1 (12 male and eight female @entity1 , mean age 47.9 years, range 26-66) with confirmed mutation in the @entity20117 gene: 13 with symptomatic @entity305 and seven asymptomatic gene carriers. A large age- and sex-matched cohort of healthy volunteers served as controls (20 male and 20 female, mean age 48.1 years, range 30-73). All @entity1 received detailed neurological and electrophysiological examinations and were scored using the @entity16 Score-Lower Limbs, @entity16 and @entity16 Symptom Score. Magnetic resonance neurography (3 T) was performed with large longitudinal coverage from proximal thigh to ankle-level and separately for each leg (140 axial slices/leg) by using axial T2-weighted (repetition time/echo time = 5970/55 ms) and dual echo (repetition time 5210 ms, echo times 12 and 73 ms) turbo spin echo 2D sequences with spectral fat saturation. A 3D T2-weighted inversion-recovery sequence (repetition time/echo time 3000/202 ms) was acquired for imaging of the spinal nerves and lumbar plexus (50 axial slice reformations). Precise @entity1930 was performed on each slice. Histogram-based normalization of nerve-voxel signal intensities was performed using the age- and sex-matched control group as normative reference. Nerve-voxels were subsequently classified as lesion-voxels if a threshold of >1.2 (normalized signal-intensity) was exceeded. At distal thigh level, where a predominant @entity66 was observed, signal quantification was performed by calculating proton spin density and T2-relaxation time as microstructural markers of nerve tissue integrity. The total number of @entity66 voxels (cumulated from proximal-to-distal) was significantly higher in symptomatic @entity1 (20 405    1586) versus asymptomatic gene carriers (12 294    3199; P = 0.036) and versus controls (6536    467; P < 0.0001). It was also higher in asymptomatic carriers compared to controls (P = 0.043). The number of @entity66 voxels was significantly higher at thigh level compared to more distal levels (lower leg/ankle) of the lower extremities (f-value = 279.22, P < 0.0001). Further signal-quantification at this proximal site (thigh level) revealed a significant increase of proton-density (P < 0.0001) and T2-relaxation-time (P = 0.0011) in symptomatic @entity1 , whereas asymptomatic gene-carriers presented with a significant increase of proton-density only. Lower @entity4218 could be detected and quantified in vivo on microstructural level by magnetic resonance neurography in symptomatic @entity14755 , and also in yet asymptomatic gene carriers, in whom imaging detection precedes clinical and electrophysiological manifestation. Although symptoms start and prevail distally, the focus of @entity128 and injury progression was found proximally at thigh level with strong and unambiguous lesion-contrast. Imaging of proximal nerve lesions, which are difficult to detect by nerve conduction studies, may have future implications also for other distally-symmetric @entity305 .
