ABSTRACT
There are two general ways in which a diagnosis of infection by Helicobacter pylori can be made: by using either an invasive or non-invasive procedure. The invasive procedures involve an endoscopy and biopsy. A biopsy is essential because often the mucosa may appear macroscopically normal but nevertheless be inflamed. A biopsy is obtained by histological examination, culture, polymerase chain reaction or detection of the presence of urease activity in biopsy material. The non-invasive tests that can be used to diagnose the infection are serology, detection of labelled metabolic products of urea hydrolysis in the breath (13CO2, 14CO2), the urine or the blood, and detection of H, pylori antigen in a stool specimen. At present no single test can be relied upon to detect definitely colonization by H. pylori, and a combination of two is recommended if this is feasible. The choice of the test to be used is not straightforward and may vary according to the clinical condition and local expertise.
Subject(s)
Helicobacter Infections/diagnosis , Helicobacter pylori , Breath Tests , Helicobacter Infections/microbiology , Helicobacter pylori/drug effects , HumansABSTRACT
Two schemes for edge detection of real images based on gradient maxima are presented. Images are filtered with narrow filters to increase localization. Experimental results and theoretical considerations suggest that the exact shape of the filter is not critical for good performance of the algorithm. Therefore a filter can be chosen to allow for a highly efficient hardware implementation, for example, a binary filter or a 4-bit finite-impulse-response filter. Because the digitized values of a binary filter are powers of 2, the hardware implementation does not require time-consuming computations, such as multiplication and time shift, but just appropriate addressings. The performance of this scheme, or a similar scheme using 4-bit filters, is as satisfactory as that of more sophisticated schemes. Therefore these low-cost schemes are likely to be more suitable for hardware implementation.
