Ultrahigh-resolution and 3-dimensional optical coherence tomography ex vivo imaging of the large and small intestines

Background: Ultrahigh-resolution optical coherence tomography (OCT) has an axial resolution of < 5 mu m, 2 to 3 times finer than standard OCT This study investigates ultrahigh-resolution and three-dimensional OCT for ex vivo imaging of the large and small intestines and correlates images with histology. Methods: Ultrahigh-resolution OCT imaging was performed on fresh surgical specimens from the large and small intestines in the pathology laboratory, and images were correlated with histology. OCT was performed at 1.3-mu m wavelength with 4.5-mu m axial x 11-mu m transverse resolution and at 1.1-mu m wavelength with 3.5-mu m axial x 6-mu m transverse resolution. Three-dimensional OCT also was investigated. Results: Normal and pathologic areas from 23 surgical specimens of the large and small intestines were imaged. Ultrahigh-resolution OCT distinguished the epithelia] layer of the mucosa and visualized individual villi, glands, and crypts. Finer transverse resolutions improved visualization of features, e.g., the epithelium, but reduced the depth of field. Architectural distortion of glands from inflammatory and neoplastic processes was observed. Three-dimensional rendering enabled visualization of surface pit pattern and mucosal folds as well as subsurface crypt microstructure. Conclusions: This study evaluates new OCT technology and can provide a baseline for interpreting future ultrahigh-resolution endoscopic OCT studies.