KEYWORDS: 3D acquisition, Endoscopy, Endoscopes, 3D image processing, 3D image reconstruction, Cancer, Image analysis, Computed tomography, Biomedical optics, Diagnostics, Cameras, 3D metrology, 3D modeling
Because the view angle of the endoscope is narrow, it is difficult to get the whole image of the digestive tract at once. If there are more than two lesions in the digestive tract, it is hard to understand the 3D positional relationship among the lesions. Virtual endoscopy using CT is a present standard method to get the whole view of the digestive tract. Because the virtual endoscopy is designed to detect the irregularity of the surface, it cannot detect lesions that lack irregularity including early cancer. In this study, we propose a method of endoscopic entire 3D image acquisition of the digestive tract using a stereo endoscope. The method is as follows: 1) capture sequential images of the digestive tract by moving the endoscope, 2) reconstruct 3D surface pattern for each frame by stereo images, 3) estimate the position of the endoscope by image analysis, 4) reconstitute the entire image of the digestive tract by combining the 3D surface pattern. To confirm the validity of this method, we experimented with a straight tube inside of which circles were allocated at equal distance of 20 mm. We captured sequential images and the reconstituted image of the tube revealed that the distance between each circle was 20.2 ± 0.3 mm (n=7). The results suggest that this method of endoscopic entire 3D image acquisition may help us understand 3D positional relationship among the lesions such as early esophageal cancer that cannot be detected by virtual endoscopy using CT.
Functional gastrointestinal disorders (FGID) are the most common gastrointestinal disorders. The term ”functional” is generally applied to disorders where there are no structural abnormalities. Gastrointestinal dysmotility is one of the several mechanisms that have been proposed for the pathogenesis of FGID and is usually examined by manometry, a pressure test. There have been no attempts to examine the gastrointestinal dysmotility by endoscopy. We have proposed an imaging system for the assessment of gastric motility using a three-dimensional endoscope. After we newly developed a threedimensional endoscope and constructed a wave simulated model, we established a method of extracting three-dimensional contraction waves derived from a three-dimensional profile of the wave simulated model obtained with the endoscope. In the study, the endoscope and the wave simulated model were fixed to the ground. However, in a clinical setting, it is hard for endoscopists to keep the endoscope still. Moreover, stomach moves under the influence of breathing. Thus, three-dimensional registration of the position between the endoscope and the gastric wall is necessary for the accurate assessment of gastrointestinal motility. In this paper, we propose a motion compensation method using three-dimensional scene flow. The scene flow of the feature point calculated by obtained images in a time series enables the three-dimensional registration of the position between the endoscope and the gastric wall. We confirmed the validity of a proposed method first by a known-movement object and then by a wave simulated model.
We propose an intestine volume measurement method using a compound eye type endoscope. This method aims at assessment of the gastrointestinal function. Gastrointestinal diseases are mainly based on morphological abnormalities. However, gastrointestinal symptoms are sometimes apparent without visible abnormalities. Such diseases are called functional gastrointestinal disorder, for example, functional dyspepsia, and irritable bowel syndrome. One of the major factors for these diseases is abnormal gastrointestinal motility. For the diagnosis of the gastrointestinal tract, both aspects of organic and functional assessment is important. While endoscopic diagnosis is essential for assessment of organic abnormalities, three-dimensional information is required for assessment of the functional abnormalities. Thus, we proposed the three dimensional endoscope system using compound eye. In this study, we forces on the volume of gastrointestinal tract. The volume of the gastrointestinal tract is thought to related its function. In our system, we use a compound eye type endoscope system to obtain three-dimensional information of the tract. The volume can be calculated by integrating the slice data of the intestine tract shape using the obtained three-dimensional information. First, we evaluate the proposed method by known-shape tube. Then, we confirm that the proposed method can measure the tract volume using the tract simulated model. Our system can assess the wall of gastrointestinal tract directly in a three-dimensional manner. Our system can be used for examination of gastric morphological and functional abnormalities.
This paper described evaluation of the three-dimensional endoscope system for assessing the gastrointestinal motility.
Gastrointestinal diseases are mainly based on the morphological or anatomical abnormity. However, sometimes the gastrointestinal
symptoms are apparent without visible abnormalities. Such diseases are called functional gastrointestinal
disorder, for example, functional dyspepsia, and irritable bowel syndrome. One of the major factors of these diseases is
the gastrointestinal dysmotility. Assessment procedures for motor function are either invasive, or indirect. We thus propose
a three-dimensional endoscope system for assessing the gastrointestinal motility. To assess the dynamic motility of
the stomach, three-dimensional endoscopic imaging of stomach lining is performed. Propagating contraction waves are
detected by subtracting estimated stomach geometry without contraction waves from one with contraction waves. After
detecting constriction waves, their frequency, amplitude, and speed of propagation can be calculated. In this study, we
evaluate the proposed system. First, we evaluate the developed three-dimensional endoscope system by a flat plane. This
system can measure the geometry of the flat plane with an error of less than 10 percent of the distance between endoscope
tip and the object. Then we confirm the validity of a prototype system by a wave simulated model. The detected wave is
approximated by a Gaussian function. In the experiment, the amplitude and position of the wave can be measure with 1
mm accuracy. These results suggest that the proposed system can measure the speed and amplitude of contraction. In the
future, we evaluate the proposed system in vivo experiments.