Figure 1.

Midline sagittal images of a supine lean Zucker rat (top) and an obese Zucker rat (bottom) during inspiration. The noninvasive grid lines were applied on these images during the preceding expiration. The transverse lines indicate the planes where the axial images were acquired and among these are eight highlighted lines that indicate the slices analyzed in this study. Axial slices 1, 4, and 6 were identified as rostral pharynx (R); slices 7, 8, and 9 as midpharynx (M); and slices 10 and 11 as caudal pharynx (C). Slices numbered 1, 4, 6, 8, and 10 are annotated for clarity. The magnetic resonance (MR) image of the obese Zucker rat shows large fat deposits near the tongue and surrounding the neck region. Ventral and dorsal sides are noted along with the tongue (Ton), nasopharynx (NP), and brain (BR), and a 1-cm scale is indicated in the image of the obese rat. Selected regions, where fat could be approximately identified in the lean and obese rats, are outlined in the images.