Abstract Details

Title Systematic Assessment of Common Error Modes in Using FIRST for MRI-based Thalamic Volumetry in People with Multiple Sclerosis

Topic Multiple Sclerosis

Presentation(s) P2 - Poster Session 2 (8:00 AM-9:00 AM)

Poster/Presentation
Number 9-010

Objective To systematically assess common thalamic segmentation errors made by FIRST on MRIs from people with Multiple Sclerosis (PwMS) and to evaluate associated anatomical variations and MRI abnormalities.

Background FSL’s FIRST is a widely-used and well-validated tool. Automated thalamic segmentation is a common application, and an important longitudinal outcome measure for MS. However, FIRST’s algorithm is based on shape-models derived from healthy controls, not from PwMS.

Design/Methods FIRST was applied to generate thalamic segmentation masks for 1,084 MR images in PwMS. Images and masks were reviewed systematically to classify and quantify errors, as well as associated anatomical variations and MRI abnormalities. For a proportionately selected sub-group (n=473), thalamic masks were manually corrected and quantitative volumetric differences were calculated.

Results Over-segmentation (incorrect inclusion of surrounding neuroanatomical structures in the thalamic mask) was the most common error mode. Specific sub-types occurred with the following frequencies: 55.44% third ventricle, 50.74% lateral ventricle, 31.92% fornix, 23.25% space medial to temporal lobe and lateral to brain stem, 16.88% cavum vergae, 13.84% septum pellucidum, and 9.44% corpus callosum. Conversely, undersegmentation (true thalamic voxels being erroneously excluded) were less frequent, but still occurred at the following frequencies: 15.77% massa intermedia, 8.30% medial thalamic nuclei, and 5.63% anterior thalamic nuclei. Concerning MRI abnormalities, 20.66% had acquisition/processing artifacts, 6.18% were highly tilted on the rostral-caudal axis, and 4.34% had motion artifacts. In the entire quantitative volumetric subgroup, the mean volumetric error of FIRST was 2.74% (0.360 mL). In the subset with errors (n=191), the mean volumetric error was 6.79% (0.894 mL).

Conclusions In PwMS, FIRST thalamic segmentation miscalculates thalamic segmentation masks in predictable ways, with the most common inclusion error occurring in ventricular spaces and most common exclusion error in the massa intermedia.

Authors/Disclosures
PRESENTER	No disclosure on file
Hannah Ferrari	No disclosure on file
Tom Fuchs (Buffalo Neuroimaging Analysis Center)	Mr. Fuchs has nothing to disclose.
	No disclosure on file
Niels Bergsland (Buffalo Neuroimaging Analysis Center / State University of New York At Buffalo)	Prof. Bergsland has nothing to disclose.
Dejan Jakimovski, MD, PhD (Buffalo Neuroimaging Analysis Center, University at Buffalo)	Dr. Jakimovski has nothing to disclose.
Bianca Weinstock-Guttman, MD (Department of Neurology, University At Buffalo)	Dr. Weinstock-Guttman has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biogen. Dr. Weinstock-Guttman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Genentech. Dr. Weinstock-Guttman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Novartis . Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for EMD Serono. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbvie. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genzyme &Sanofi. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen . Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Horizon. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Weinstock-Guttman has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Weinstock-Guttman has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Biogen. Dr. Weinstock-Guttman has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Janssen. Dr. Weinstock-Guttman has received personal compensation in the range of $0-$499 for serving as a Reviewer with NIH.
Robert Zivadinov, MD, PhD, F�鶹��ýӳ�� (Buffalo Neuroimaging Analysis Center)	The institution of Dr. Zivadinov has received personal compensation in the range of $500-$4,999 for serving as a Consultant for BMS. The institution of Dr. Zivadinov has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Omnicuris. The institution of Dr. Zivadinov has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Myrobalan. Dr. Zivadinov has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Sanofi. Dr. Zivadinov has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for EMD Serono. Dr. Zivadinov has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Bristol Myers Squibb. The institution of Dr. Zivadinov has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Biogen.
Michael G. Dwyer III, MD, PhD (Buffalo Neurological Analysis Center)	Dr. Dwyer has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bristol Myers Squibb. Dr. Dwyer has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Keystone Heart, Ltd. Dr. Dwyer has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. The institution of Dr. Dwyer has received research support from Novartis. The institution of Dr. Dwyer has received research support from Keystone Heart, Ltd. The institution of Dr. Dwyer has received research support from Bristol Myers Squibb. The institution of Dr. Dwyer has received research support from Roche.

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