Abstract #0904

Helium-3 Magnetic Resonance Imaging of Treatment Response in Exercise Induced Bronchoconstriction

Stanley John Kruger¹, David Niles¹, Grace Parraga², Sean Fain¹, Bernard Dardzinski³, Marcella Ruddy³, Amy Harman³, Stephen Choy², Scott Nagle⁴, Christopher Francois⁴, David G. McCormack², Nizar Jarjour⁵

¹Medical Physics, University of Wisconsin, Madison, WI, United States; ²Robarts Imaging Institution, University of Western Ontario, London, ON, Canada; ³Merck Research Labs, West Point, PA, United States; ⁴Radiology, University of Wisconsin, Madison, WI, United States; ⁵Medicine & Public Health, University of Wisconsin, Madison, WI, United States

A double blind therapy trial using He-3 MRI was conducted to evaluate efficacy for exercise induced bronchoconstriction (EIB) using images of ventilation. To track regional changes in defect volume as an endpoint for treatment effect, He-3 MRI was performed at three separate visits at baseline, exercise challenge and 45 min. after challenge in 13 subjects with EIB. Drug was given at 1 of the visits, and placebo at the remaining visits. Results show decreases in ventilation volume at exercise challenge compared to baseline, with treatment reducing this effect. Both decrease in ventilation volume and treatment effect showed preferential regional behavior.