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Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA.

El Mendili MM, Lenglet T, Stojkovic T, Behin A, Guimarães-Costa R, Salachas F, Meininger V, Bruneteau G, Le Forestier N, Laforêt P, Lehéricy S, Benali H, Pradat PF - PLoS ONE (2016)

Bottom Line: Patients were scored on manual muscle testing and functional scales.RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10-5).There were no correlations between atrophy measurements, strength and disability scores.

View Article: PubMed Central - PubMed

Affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, F-75013, Paris, France.

ABSTRACT

Purpose: The mechanisms underlying the topography of motor deficits in spinal muscular atrophy (SMA) remain unknown. We investigated the profile of spinal cord atrophy (SCA) in SMN1-linked SMA, and its correlation with the topography of muscle weakness.

Materials and methods: Eighteen SMN1-linked SMA patients type III/V and 18 age/gender-matched healthy volunteers were included. Patients were scored on manual muscle testing and functional scales. Spinal cord was imaged using 3T MRI system. Radial distance (RD) and cord cross-sectional area (CSA) measurements in SMA patients were compared to those in controls and correlated with strength and disability scores.

Results: CSA measurements revealed a significant cord atrophy gradient mainly located between C3 and C6 vertebral levels with a SCA rate ranging from 5.4% to 23% in SMA patients compared to controls. RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10-5). There were no correlations between atrophy measurements, strength and disability scores.

Conclusions: Spinal cord atrophy in adult SMN1-linked SMA predominates in the segments innervating the proximal muscles. Additional factors such as neuromuscular junction or intrinsic skeletal muscle defects may play a role in more complex mechanisms underlying weakness in these patients.

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Related in: MedlinePlus

Spinal cord segmentation, cord straightening and radial distance illustration.(A) Preprocessed T2-weighted mid-sagittal section in an SMA patient. The yellow dashed lines delimit the cervical spinal cord region. (B) Resulted segmentation mask (orange). (C) Cervical spinal cord straightening. (D) Mask straightening (orange). (E) Radial distance measurements. A, anterior; I, inferior; L, left, P, posterior, R, right, S, superior.
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pone.0152439.g001: Spinal cord segmentation, cord straightening and radial distance illustration.(A) Preprocessed T2-weighted mid-sagittal section in an SMA patient. The yellow dashed lines delimit the cervical spinal cord region. (B) Resulted segmentation mask (orange). (C) Cervical spinal cord straightening. (D) Mask straightening (orange). (E) Radial distance measurements. A, anterior; I, inferior; L, left, P, posterior, R, right, S, superior.

Mentions: Data were corrected for non-uniformity intensity using Minc-Toolkit N3 [10]. Two landmarks have been manually defined in the sagittal slice where the spinal cord was the most median in the FOV by an experienced operator on spinal cord MRI segmentation techniques (M.-M. E. M., 5 years of experience, among the authors), to delimit the cervical spinal cord (i.e. from the upper limit of the odontoid process of the C2 vertebrae to the middle vertebral body C7/T1) [11, 12]. Data were cropped and resampled to a voxel size of 0.3×0.3×0.3 mm3 using 3D cubic interpolation in order to maximize segmentation accuracy [12–14]. Fig 1A shows a preprocessed mid-sagittal section in an SMA patient.


Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA.

El Mendili MM, Lenglet T, Stojkovic T, Behin A, Guimarães-Costa R, Salachas F, Meininger V, Bruneteau G, Le Forestier N, Laforêt P, Lehéricy S, Benali H, Pradat PF - PLoS ONE (2016)

Spinal cord segmentation, cord straightening and radial distance illustration.(A) Preprocessed T2-weighted mid-sagittal section in an SMA patient. The yellow dashed lines delimit the cervical spinal cord region. (B) Resulted segmentation mask (orange). (C) Cervical spinal cord straightening. (D) Mask straightening (orange). (E) Radial distance measurements. A, anterior; I, inferior; L, left, P, posterior, R, right, S, superior.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835076&req=5

pone.0152439.g001: Spinal cord segmentation, cord straightening and radial distance illustration.(A) Preprocessed T2-weighted mid-sagittal section in an SMA patient. The yellow dashed lines delimit the cervical spinal cord region. (B) Resulted segmentation mask (orange). (C) Cervical spinal cord straightening. (D) Mask straightening (orange). (E) Radial distance measurements. A, anterior; I, inferior; L, left, P, posterior, R, right, S, superior.
Mentions: Data were corrected for non-uniformity intensity using Minc-Toolkit N3 [10]. Two landmarks have been manually defined in the sagittal slice where the spinal cord was the most median in the FOV by an experienced operator on spinal cord MRI segmentation techniques (M.-M. E. M., 5 years of experience, among the authors), to delimit the cervical spinal cord (i.e. from the upper limit of the odontoid process of the C2 vertebrae to the middle vertebral body C7/T1) [11, 12]. Data were cropped and resampled to a voxel size of 0.3×0.3×0.3 mm3 using 3D cubic interpolation in order to maximize segmentation accuracy [12–14]. Fig 1A shows a preprocessed mid-sagittal section in an SMA patient.

Bottom Line: Patients were scored on manual muscle testing and functional scales.RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10-5).There were no correlations between atrophy measurements, strength and disability scores.

View Article: PubMed Central - PubMed

Affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, F-75013, Paris, France.

ABSTRACT

Purpose: The mechanisms underlying the topography of motor deficits in spinal muscular atrophy (SMA) remain unknown. We investigated the profile of spinal cord atrophy (SCA) in SMN1-linked SMA, and its correlation with the topography of muscle weakness.

Materials and methods: Eighteen SMN1-linked SMA patients type III/V and 18 age/gender-matched healthy volunteers were included. Patients were scored on manual muscle testing and functional scales. Spinal cord was imaged using 3T MRI system. Radial distance (RD) and cord cross-sectional area (CSA) measurements in SMA patients were compared to those in controls and correlated with strength and disability scores.

Results: CSA measurements revealed a significant cord atrophy gradient mainly located between C3 and C6 vertebral levels with a SCA rate ranging from 5.4% to 23% in SMA patients compared to controls. RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10-5). There were no correlations between atrophy measurements, strength and disability scores.

Conclusions: Spinal cord atrophy in adult SMN1-linked SMA predominates in the segments innervating the proximal muscles. Additional factors such as neuromuscular junction or intrinsic skeletal muscle defects may play a role in more complex mechanisms underlying weakness in these patients.

Show MeSH
Related in: MedlinePlus