Correlating Function and Imaging Measures of the Medial Longitudinal Fasciculus

PLoS One. 2016 Jan 22;11(1):e0147863. doi: 10.1371/journal.pone.0147863. eCollection 2016.

Abstract

Objective: To test the validity of diffusion tensor imaging (DTI) measures of tissue injury by examining such measures in a white matter structure with well-defined function, the medial longitudinal fasciculus (MLF). Injury to the MLF underlies internuclear ophthalmoparesis (INO).

Methods: 40 MS patients with chronic INO and 15 healthy controls were examined under an IRB-approved protocol. Tissue integrity of the MLF was characterized by DTI parameters: longitudinal diffusivity (LD), transverse diffusivity (TD), mean diffusivity (MD) and fractional anisotropy (FA). Severity of INO was quantified by infrared oculography to measure versional disconjugacy index (VDI).

Results: LD was significantly lower in patients than in controls in the medulla-pons region of the MLF (p < 0.03). FA was also lower in patients in the same region (p < 0.0004). LD of the medulla-pons region correlated with VDI (R = -0.28, p < 0.05) as did FA in the midbrain section (R = 0.31, p < 0.02).

Conclusions: This study demonstrates that DTI measures of brain tissue injury can detect injury to a functionally relevant white matter pathway, and that such measures correlate with clinically accepted evaluation indices for INO. The results validate DTI as a useful imaging measure of tissue integrity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain Injuries / pathology*
  • Diffusion Tensor Imaging*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Ophthalmoplegia / pathology
  • White Matter / pathology

Grants and funding

The authors gratefully acknowledge support from the National Multiple Sclerosis Society (RG 4091 A3/1) and from the DADs Foundation. Philips Medical system provided support in the form of salary for Dr. Dimitrov, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of Dr. Diomitrov are articulated in the "author contributions" section. Dr. Fox received research grant funding from Novartis.