Quantitative magnetic resonance imaging of upper airway musculature
in an animal model of sleep apnea.
Schotland, Helena M., Erik K. Insko, Karen A. Panckeri, John S. Leigh,
Allan I. Pack, and Joan C. Hendricks.
Pulmonary and Critical Care Division, Department of Medicine;
Metabolic Magnetic Resonance Research and Computing Center,
Department of Radiology; Center for Sleep and Respiratory
Neurobiology, University of Pennsylvania School of Medicine,
Philadelphia, PA 19104, Department of Clinical Studies, University of
Pennsylvania School of Veterinary Medicine, Philadelphia, PA
19104
APStracts 3:0237A, 1996.
Electromyographic studies of patients with sleep apnea and of the
English bulldog, an animal model of sleep apnea, indicate that there
is increased activity of the airway dilator muscles. The muscles,
when biopsied, show both adaptation and muscle injury. In this study
we have utilized quantitative magnetic resonance imaging to
characterize changes in the upper airway musculature of the bulldog
in vivo. The imaging procedure utilized provided a quantitative
measurement of the T2 relaxation times of airway muscles (geniohyoid,
sternohyoid, sternothyroid, thyropharyngeus, and hyopharyngeus) and
non-airway muscles spatially localized to submillimeter resolution
levels. Quantitative differences between the medians and
distributions of T2 relaxation times of airway vs. non-airway muscles
were demonstrated. These differences were related to the degree of
sleep-disordered breathing. The changes observed are compatible with
the hypothesis that there is both increased edema and fibrosis in
upper airway muscles in sleep apnea.
Received 6 November 1995; accepted in final form 24 April 1996.
APS Manuscript Number A1175-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 May 96