Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Feb 1;39(2):423-8.
doi: 10.5665/sleep.5456.

Microstructure of the Midbrain and Cervical Spinal Cord in Idiopathic Restless Legs Syndrome: A Diffusion Tensor Imaging Study

Klaas Lindemann  1 , Hans-Peter Müller  1 , Albert C Ludolph  1 , Magdolna Hornyak  1   2 , Jan Kassubek  1
Affiliations

Microstructure of the Midbrain and Cervical Spinal Cord in Idiopathic Restless Legs Syndrome: A Diffusion Tensor Imaging Study

Klaas Lindemann et al. Sleep. .

Abstract

Study objectives: Diffusion tensor imaging (DTI) allows the study of white matter microstructure in the central nervous system. The aim of this study was to examine the DTI metrics of the cervical spinal cord and the brainstem up to the midbrain in patients with idiopathic restless legs (RLS) compared to matched healthy controls.

Methods: DTI analysis of the cervical spinal cord and the brainstem up into the midbrain was performed in 25 patients with idiopathic RLS and 25 matched healthy controls. Data analysis in the brain was performed by voxelwise comparison of fractional anisotropy (FA) maps at group level. Cervical spinal cord data analysis was performed by slicewise analysis of averaged FA values in axial slices along the spinal cord.

Results: Voxelwise comparison of FA maps in the brainstem showed significant microstructural alterations in two clusters in the midbrain bilaterally. Slicewise comparison of the FA maps in the cervical spinal cord showed a trend for lower FA values at the level of the second and third vertebra area in the patient sample.

Conclusions: The imaging data suggest that significant alterations in the midbrain in RLS can be visualized by DTI and might correlate to a macroscopically subtle process with changes of the tissue microstructure in the corresponding tracts. An additional area of interest is regionally clustered in the upper cervical spinal cord with a tendency toward altered diffusion metrics. These results might be addressed by further studies, e.g., at higher magnetic field strengths.

Keywords: diffusion tensor imaging; magnetic resonance imaging; midbrain; restless legs syndrome; spinal cord; substantia nigra.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Illustration of the normalization process. (A) Sagittal reconstruction of axial DTI scans – FA map (blue = apical-basal), crosshairs at apex dentis. Background is the (b = 0)-scan. (B) Sagittal morphological T1w scan to calculate the distance between apex dentis and seventh vertebra, as indicated by lines. (C) Axially normalized FA map of (A). (D) Template obtained from axially normalized FA maps; slices of interest (SOIs) are indicated by horizontal lines. DTI, diffusion tensor imaging; FA, fractional anisotrophy.
Figure 2
Figure 2
Voxelwise comparison of fractional anisotrophy (FA) maps (whole brain-based spatial statistics [WBSS]) of patients and controls with significance level at P < 0.05. Values are false discovery rate (FDR)-corrected and revealed two significant clusters in the midbrain bilaterally.
Figure 3
Figure 3
(A) Group differences between patients with restless legs syndrome (RLS) and controls of fractional anisotrophy (FA) values in operator-defined slices of interest (SOI) within the spinal cord. (B) Group averaged slicewise FA values along the cervical spinal cord for patients with RLS (red) and controls (blue). (C) Differences along the cervical spinal cord (T test values, significance level P < 0.05, uncorrected).
See this image and copyright information in PMC

References

    1. Berger K, Kurth T. RLS epidemiology - frequencies, risk factors and methods in population studies. Mov Disord. 2007;18:S420–3. - PubMed
    1. Allen RP, Picchietti D, Hening WA, Trenkwalder C, Walters AS, Montplaisir J. Restless legs syndrome: diagnostic criteria, special considerations and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med. 2003;4:101–19. - PubMed
    1. Trenkwalder C, Paulus W, Walters AS. The restless legs syndrome. Lancet Neurol. 2005;4:465–75. - PubMed
    1. Ondo WG, He Y, Rajasekaran S, Le WD. Clinical correlates of 6-hydroxydopamine injections into A11 dopaminergic neurons in rats: a possible model for restless legs syndrome. Mov Disord. 2000;15:154–8. - PubMed
    1. Allen RP, Barker PB, Wehrl F, Song HK, Earley CJ. MRI measurement of brain iron in patients with restless legs syndrome. Neurology. 2001;56:263–5. - PubMed