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
. 2017 Oct 26;17(1):194.
doi: 10.1186/s12883-017-0975-2.

Ultra high-field SWI of the substantia nigra at 7T: reliability and consistency of the swallow-tail sign

Manuel A Schmidt  1 , Tobias Engelhorn  2 , Franz Marxreiter  3 , Juergen Winkler  3 , Stefan Lang  2 , Stephan Kloska  2 , Philipp Goelitz  2 , Arnd Doerfler  2
Affiliations

Ultra high-field SWI of the substantia nigra at 7T: reliability and consistency of the swallow-tail sign

Manuel A Schmidt et al. BMC Neurol. .

Abstract

Background: The loss of the swallow-tail sign of the substantia nigra has been proposed for diagnosis of Parkinson's disease. Aim was to evaluate, if the sign occurs consistently in healthy subjects and if it can be reliably detected with high-resolution 7T susceptibility weighted imaging (SWI).

Methods: Thirteen healthy adults received SWI at 7T. 3 neuroradiologists, who were blinded to patients' diagnosis, independently classified subjects regarding the swallow-tail sign to be present or absent. Accuracy, positive and negative predictive values (PPV and NPV) as well as inter- and intra-rater reliability and internal consistency were analyzed.

Results: The sign could be detected in 81% of the cases in consensus reading. Accuracy to detect the sign compared to the consensus was 100, 77 and 96% for the three readers with PPV reader 1/2/3 = 1/0.45/0.83 and NPV = 1/1/1. Inter-rater reliability was excellent (inter-class correlation coefficient = 0.844, alpha = 0.871). Intra-rater reliability was good to excellent (reader 1 R/L = 0.625/0.786; reader 2 = 0.7/0.64; reader 3 = 0.9/1).

Conclusion: The swallow-tail sign can be reliably detected. However, our data suggest its occurrence is not consistent in healthy subjects. It may be possible that one reason is an individually variable molecular organization of nigrosome 1 so that it does not return a uniform signal in SWI.

Keywords: 7 tesla; Nigrosome 1; Parkinson’s disease; SWI; Swallow-tail sign; Ultra high-field MRI.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

The Clinical Investigation Ethics Committee of the University of Erlangen-Nuremberg approved the protocol of this prospective study and the research was conducted in accordance with the Declaration of Helsinki. All participants gave written informed consent prior to all measurements and agreed upon publication.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
a Oblique-axial 1 mm MPR depicting the SN in two healthy subjects. Different slices for demonstration purposes. b Nigrosome 1 and consequently the swallow-tail sign can be readily visualized (filled arrow). c Absent swallow-tail sign (arrow)
Fig. 2
Fig. 2
Inconsistent occurrence of the swallow-tail sign in healthy subjects. a-c Clearly definable swallow-tail of the dorsolateral SNc. d The swallow-tail can only be identified on the right side (filled arrow). e-f No swallow-tail sign can be detected (arrows)
Fig. 3
Fig. 3
Healthy subject. Pulsation artifacts of the superior cerebelli artery could potentially disguise the swallow-tail sign (despite being recognizable in this case) leading to misclassification
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Vaillancourt DE, Spraker MB, Prodoehl J, Abraham I, Corcos DM, Zhou XJ, Comella CL, Little DM. High-resolution diffusion tensor imaging in the substantia nigra of de novo Parkinson disease. Neurology. 2009;72(16):1378–1384. doi: 10.1212/01.wnl.0000340982.01727.6e. - DOI - PMC - PubMed
    1. Schwarz ST, Abaei M, Gontu V, Morgan PS, Bajaj N, Auer DP. Diffusion tensor imaging of nigral degeneration in Parkinson's disease: a region-of-interest and voxel-based study at 3 T and systematic review with meta-analysis. NeuroImage Clin. 2013;3:481–488. doi: 10.1016/j.nicl.2013.10.006. - DOI - PMC - PubMed
    1. Lotfipour AK, Wharton S, Schwarz ST, Gontu V, Schafer A, Peters AM, Bowtell RW, Auer DP, Gowland PA, Bajaj NP. High resolution magnetic susceptibility mapping of the substantia nigra in Parkinson's disease. J Magn Reson Imaging. 2012;35(1):48–55. doi: 10.1002/jmri.22752. - DOI - PubMed
    1. Damier P, Hirsch EC, Agid Y, Graybiel AM. The substantia nigra of the human brain. I. Nigrosomes and the nigral matrix, a compartmental organization based on calbindin D(28K) immunohistochemistry. Brain. 1999;122(Pt 8):1421–1436. doi: 10.1093/brain/122.8.1421. - DOI - PubMed
    1. Blazejewska AI, Schwarz ST, Pitiot A, Stephenson MC, Lowe J, Bajaj N, Bowtell RW, Auer DP, Gowland PA. Visualization of nigrosome 1 and its loss in PD: pathoanatomical correlation and in vivo 7 T MRI. Neurology. 2013;81(6):534–540. doi: 10.1212/WNL.0b013e31829e6fd2. - DOI - PMC - PubMed