Abstract Details

Title Prevalence of Hyperintense White Matter Lesions in Very-Low-Pressure Hypobaric Physiology Technicians

Topic Neurotoxicology

Presentation(s) P06 - (-)

Poster/Presentation
Number 203

Objective

Background BACKGROUND: Repetitive exposure to very high altitudes leads to persistent HWM signal change on Fluid Attenuated Inversion Recovery (FLAIR) MRI and impacts cognition in U-2 pilots. Hypobaric physiology technicians are also routinely exposed to very-low-pressure conditions, and we postulated that they would demonstrate similar MRI abnormalities.

Design/Methods DESIGN/METHODS: We compared 36 physiology technicians with at least 50 exposures to altitudes above 20,000ft to 67 age-matched, healthy, active duty Air Force officers without history of neurologic disease. 3D FLAIR MRI high-resolution (isotropic 800[mu]m) data acquired on a 3T Siemens scanner was analyzed for HWM lesions. Quantitative measurement of HWM lesions was performed as previously described. Data was analyzed using the non-parametric Mann-Whitney test. We considered a p?0.05 significant and 0.10?p>0.05 as suggesting a trend towards significance.

Results RESULTS: All participants underwent MRI. Data compared between hypobaric physiology technicians and Air Force officers, respectively: HWM subcortical volume (0.179cc±0.576; 0.040cc±0.044; p=0.073); HWM subcortical count (8.19±14.31; 3.30±4.28; p=0.045), total FLAIR volume (0.377cc±0.592; 0.592cc±0.142; p=0.378), and total ependymal volume (0.199cc±0.089; 0.215cc±0.111; p=0.614).

Conclusions CONCLUSIONS: Our findings indicate a trend towards increased volume and number of subcortical HWM lesions in physiology technicians occupationally exposed to extremely high altitudes, similar to that observed in U-2 pilots. Based on lesion distribution, we postulate an underlying inflammatory vs. enhanced thrombotic process, possibly secondary to venous nitrogen bubble formation, rather than direct gas bubble occlusion of an arterial vessel. Further investigation of mechanism of injury and extent of cognitive effects of such lesions is warranted. Future directions of this project include analysis of overlying cortical thickness, fractional anisotropy of white matter tracts, spectroscopy analysis, and serological biomarker assay.

Authors/Disclosures
Caelan M. Ford, MD (United States Air Force) PRESENTER	No disclosure on file
John H. Sladky, MD, FAAN (San Antonio Military Medical Center/MCHE MDU)	Dr. Sladky has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Stephen A. McGuire, MD, FAAN	No disclosure on file
Vincenzo Brescia Morra, MD (Universita Federico II - Napoli)	Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for NOVARTIS. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for BIOGEN. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ROCHE. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for TEVA. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ALMIRALL. Dr. Brescia Morra has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for MERK. Dr. Brescia Morra has received personal compensation in the range of $0-$499 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for MERK. The institution of Dr. Brescia Morra has received research support from FISM. Dr. Brescia Morra has a non-compensated relationship as a PI with FISM that is relevant to AAN interests or activities.

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