The aim of the Expert Approach section is to contribute to the dissemination and standardization of new endoscopic procedures. Authors from three distinct geographic areas combine forces, sharing their experience to form a consensus of opinion. Readers' comments are welcome and will be published in the Mailbox which appears at the end of each Expert Approach article.
[Show abstract][Hide abstract] ABSTRACT: Objective evaluation of dynamic imaging protocols needs a
realistic simulation tool to model the data acquisition and image
reconstruction of a PET system. Availability of the correlated
functional and anatomical images in many centers allows the creation of
highly realistic objects to represent brain activity and attenuation
distribution for each study. The authors have developed a fast
analytical model that incorporates key physical factors inherent in
coincidence detection along with spatially variant 3-D detection
efficiency and deadtime. Here, they use MR and PET data of a 3-D Hoffman
brain phantom to demonstrate and validate their computational methods.
The simulated total projection, attenuation factor: and scatter profiles
are in very good agreement with the experimental data. The corresponding
regional activity values in the gray matter and white matter have a
discrepancy of ⩽8.5%. The authors also show typical emission and
transmission images generated from MR brain scans. This tool is
particularly useful in evaluating projection data processing and image
[Show abstract][Hide abstract] ABSTRACT: Portal hypertensive gastropathy (PHG) is an extremely common endoscopic finding in patients with portal hypertension. This article examines the various endoscopic grading systems that have been developed for PHG with further discussion on the risk of bleeding with PHG and if endoscopic grading can predict the risk of bleeding. Finally, both the nonendoscopic and endoscopic treatment modalities for acute and chronic bleeding secondary to PHG are discussed.
Techniques in Gastrointestinal Endoscopy 01/2005; 7(1):37-40. DOI:10.1016/j.tgie.2004.10.009
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