Elsevier

Epilepsy Research

Volume 108, Issue 2, February 2014, Pages 336-339
Epilepsy Research

Short communication
Advanced diffusion imaging sequences could aid assessing patients with focal cortical dysplasia and epilepsy

https://doi.org/10.1016/j.eplepsyres.2013.11.004Get rights and content
Under a Creative Commons license
open access

Highlights

  • Malformations of cortical development are a common cause of refractory epilepsy.

  • They are often invisible on structural imaging and only detected following surgery.

  • We assess a novel diffusion imaging technique (NODDI) in patients with dysplasia.

  • This shows more conspicuous changes than other clinical or diffusion scans.

  • This technique may assist the identification of FCD in patients with epilepsy.

Summary

Malformations of cortical development (MCD), particularly focal cortical dysplasia (FCD), are a common cause of refractory epilepsy but are often invisible on structural imaging. NODDI (neurite orientation dispersion and density imaging) is an advanced diffusion imaging technique that provides additional information on tissue microstructure, including intracellular volume fraction (ICVF), a marker of neurite density.

We applied this technique in 5 patients with suspected dysplasia to show that the additional parameters are compatible with the underlying disrupted tissue microstructure and could assist in the identification of the affected area.

The consistent finding was reduced ICVF in the area of dysplasia. In one patient, an area of reduced ICVF and increased fibre dispersion was identified that was not originally seen on the structural imaging. The focal reduction in ICVF on imaging is compatible with previous iontophoretic data in surgical specimens, was more conspicuous than on other clinical or diffusion images (supported by an increased contrast-to-noise ratio) and more localised than on previous DTI studies.

NODDI may therefore assist the clinical identification and localisation of FCD in patients with epilepsy. Future studies will assess this technique in a larger cohort including MRI negative patients.

Abbreviations

CNR
contrast-to-noise ratio
CSF
cerebrospinal fluid
FA
fractional anisotropy
FCD
focal cortical dysplasia
FLAIR
fluid-attenuated inversion recovery
ICVF
intracellular volume fraction
ITG
inferior temporal gyrus
MCD
malformations of cortical development
MD
mean diffusivity
MFG
middle frontal gyrus
MRI
magnetic resonance imaging
NODDI
neurite orientation dispersion and density imaging
ODI
orientation dispersion index
PROPELLER
periodically rotated overlapping parallel lines with enhanced reconstruction

Keywords

Diffusion imaging
Focal cortical dysplasia
Epilepsy surgery
NODDI
Neurite density

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