Individual variations in mucosa and total wall thickness in the stomach and rectum assessed via endoscopic ultrasound

Endoscopic ultrasound is a unique tool to acquire in vivo data on alimentary tract wall thicknesses of sufficient resolution needed in radiation dosimetry studies. Through their different echo texture and intensity, five layers of differing echo patterns for superficial mucosa, deep mucosa, submucosa, muscularis externa and serosa/adventitia exist within the walls of organs composing the alimentary tract. In this study, retrospective image analyses of patient video data were made for ten examinations of the stomach and eight examinations of the rectum covering a range of patient ages. Thicknesses for stomach mucosa ranged from 1030 ± 130 μm to 1640 ± 80 μm (total stomach wall thicknesses from 2.80 ± 0.12 to 4.23 ± 0.03 mm). Measurements made for the rectal images revealed rectal mucosal thicknesses from 660 ± 50 μm to 1130 ± 250 μm (total rectal wall thicknesses from 2.28 ± 0.05 to 3.55 ± 0.43 mm). The mucosa accounted for ∼32 ± 7% and ∼32 ± 8% of the total thickness of the stomach and rectal wall, respectively. These values can thus be utilized to investigate uncertainties in alimentary tract dosimetry that are based upon fixed reference individual definitions of organ wall structure.