Abstract Details

Title Myelin Mapping in Trigeminal Neuralgia: Standardizing Conventional MR Images Enables Quantitative Comparison of Myelin Content

Topic Multiple Sclerosis

Presentation(s) P15 - Poster Session 15 (5:30 PM-6:30 PM)

Poster/Presentation
Number 12-003

Background Novel magnetic resonance (MR) imaging techniques prompted the development of MMs to estimate myelin content in vivo. However, acquisition-related variations in MR intensities prevent meaningful comparisons between MMs. We propose an improved pipeline to standardize MMs that is applied to patients with classic trigeminal neuralgia (CTN) and trigeminal neuralgia secondary to multiple sclerosis (MSTN).

Objective

1) To develop an improved pipeline that standardizes T1-w/T2-w images or "myelin maps (MM)".

2) To validate this pipeline in patients with classic trigeminal neuralgia (CTN) and trigeminal neuralgia secondary to multiple sclerosis (MSTN).

Design/Methods

T1-w and T2-w images were obtained for 17 CTN and 17 MSTN patients. Multiple sclerosis (MS) plaques and normal-appearing white matter (NAWM) were labelled in MSTN patients. Template images, gray matter (GM) masks, and white matter (WM) masks were acquired from the ICBM152 database. For each patient image, a Gaussian curve-fit was applied to the histogram of the intensity distribution and transformed to match the Gaussian curve-fit of its template image. Gaussian curve-fits were also performed to obtain the mean intensities of GM, WM, MS plaques, and NAWM.

Results Qualitatively, the standardized patient image and its histogram better resembled the ICBM152 template. Quantitatively, there was significantly reduction in the variability of GM and WM histogram peaks between patients after standardization, compared to pre-standardization (p<0.001). Further analysis reveals decreased MM intensities within MS plaques, compared to NAWM in MSTN patients (p<0.001) and its corresponding regions in CTN patients (p<0.001).

Conclusions

Reduced variability in GM and WM histogram peaks among patients permits meaningful inter-subject comparisons. MM analysis revealed reduced myelin content in MS plaques compared to corresponding regions in CTN patients and surrounding NAWM in MSTN patients. The standardized MM serves as a non-invasive tool for quantitative analyses of myelin content between different brain regions and different patients in vivo.

Authors/Disclosures
Meng Fei Li, MD (London Health Sciences Centre) PRESENTER	Dr. Li has nothing to disclose.
	No disclosure on file
	No disclosure on file
David J. Mikulis, MD (Toronto Hosp Western Div)	Dr. Mikulis has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Neinstein Personal Injury Lawyers. Dr. Mikulis has received stock or an ownership interest from Thornhill Medical, Inc.. Dr. Mikulis has received intellectual property interests from a discovery or technology relating to health care.
	No disclosure on file