ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

50000 images have been acquired. The analysis of this huge amount of data is done in a
workstation, visualizing the images as video by an expert physician and takes 40-60
minutes. To make the analysis, the physician has to be highly focused to minimize
failures in the diagnosis. Computer assisted diagnosis can reduce these errors and also
decrease costs, as having an expert analyzing the exam for such long period is an
important parcel in the total cost of the exam.
Image processing techniques can improve and enhance the information contained in the
original images. Additionally, image analysis techniques, such as image segmentation,
have a crucial role in extracting high-level information from the processed images.
Up to now, white light endoscopy is the main method in detection of GI tumors. Whitelight
endoscopy is well established and widely used. We studied, in this project, a new
diagnostic module, based on tissue autofluorescence (AFI) or NBI, since conventional
white light is suboptimal and usually detects lesions, which already have symptoms of
obstruction, bleeding and pain, related to tumor growth. AFI and NBI are innovative
techniques that improve the identification and localization of malignant lesions [2, 3].
AFI is based on the principles of tissue excitation with a shorter wavelength, which
leads to emission of a longer wavelength of light. To perform “autofluorescence” a
fluorescent drug has to be administered. NBI is a novel endoscopic technique which
alters the wavelength of illumination light used, making the center wavelength shorter
compared to standard white light. Under NBI, superficial structures in mucosa, like
microcapillaries are selectively highlighted due to the shallower penetration of mucosa
with blue and green lights. The scientific basis for NBI is that short wavelength light
falls within the hemoglobin absorption band, thereby facilitating clearer visualization of
vascular structures due to sufficient contrast. The depth of penetration into the GI tract
mucosa is superficial for the blue band, intermediate for the green band and deep for the
red band (penetration depth range: 0.15 to 0.30 mm).
3. STATE OF THE ART
3.1 Image acquisition
Capsule Endoscopy is based on a miniature capsule that is used to visualize and record
images through the digestive tract. Capsule endoscopy has other names such as Wireless
capsule endoscopy, Miniature Ingestible Capsule, and is marketed as EndoCapsule by
Olympus and PillCam by Given Imaging. The capsule is an imaging device that can be
very useful for the early detection of gastrointestinal diseases and is considered as a
major breakthrough in medical technology. Due to the fact that the capsule is swallowed
and travels through the entire digestive tract, capsule endoscopy takes a longer amount
of time than traditional endoscopy. Research has shown that EC can detect evidence of
disease in some cases that traditional endoscopy cannot.
Problems like navigation of the capsule and real-time viewing of the study images,
which may take several hours, have been surpassed. There are some companies that
already have a capsule that takes pictures from the gastrointestinal tract that will form a
video. Two of the main companies in this type of technology are: Given Imaging with
the PillCam system from Israel/ USA and Olympus with the Capsule Endoscope from
Japan. But also from Japan, RF Systems Co. announced Sayaka capsule endoscope,
from China, Jinshan Science and Technology Company, developed capsule endoscope
system OMOM, and from Korea, the company IntroMedic, developed its capsule
endoscope system MIROCAM [1]. Meanwhile Olympus and Siemens announced the
development of a technology for a magnetically guided capsule endoscope (MGCE)
system for controlling magnetically capsule.