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Biomedical subjects

F Maes

Publications and source records attributed to F Maes.

26 records · Page 2Linked to original sources
PubMed1981

Significance of persisting IgM anti-HBc antibodies in hepatitis B virus infection.

Igg and IgM antibodies to the core antigen of hepatitis B virus (HBV) were measured in 136 patients who developed acute HBV hepatitis and who were followed prospectively. After acute hepatitis all the patients developed transiently IgM anti-HBc lasting for two to five months. In contrast, IgM anti-HBc persisted 8 and 9 months in two patients who developed persistent hepatitis and were continuously detected for two years in nine patients who developed aggressive hepatitis. The results suggest that the determination of IgM anti-HBc might be useful to predict the outcome of chronic hepatitis B infection.

Acute Disease↗
PubMedDate not supplied

Comparison and evaluation of retrospective intermodality brain image registration techniques.

PURPOSE: The primary objective of this study is to perform a blinded evaluation of a group of retrospective image registration techniques using as a gold standard a prospective, marker-based registration method. To ensure blindedness, all retrospective registrations were performed by participants who had no knowledge of the gold standard results until after their results had been submitted. A secondary goal of the project is to evaluate the importance of correcting geometrical distortion in MR images by comparing the retrospective registration error in the rectified images, i.e., those that have had the distortion correction applied, with that of the same images before rectification. METHOD: Image volumes of three modalities (CT, MR, and PET) were obtained from patients undergoing neurosurgery at Vanderbilt University Medical Center on whom bone-implanted fiducial markers were mounted. These volumes had all traces of the markers removed and were provided via the Internet to project collaborators outside Vanderbilt, who then performed retrospective registrations on the volumes, calculating transformations from CT to MR and/ or from PET to MR. These investigators communicated their transformations again via the Internet to Vanderbilt, where the accuracy of each registration was evaluated. In this evaluation, the accuracy is measured at multiple volumes of interest (VOIs), i.e., areas in the brain that would commonly be areas of neurological interest. A VOI is defined in the MR image and its centroid c is determined. Then, the prospective registration is used to obtain the corresponding point c' in CT or PET. To this point, the retrospective registration is then applied, producing c" in MR. Statistics are gathered on the target registration error (TRE), which is the distance between the original point c and its corresponding point c". RESULTS: This article presents statistics on the TRE calculated for each registration technique in this study and provides a brief description of each technique and an estimate of both preparation and execution time needed to perform the registration. CONCLUSION: Our results indicate that retrospective techniques have the potential to produce satisfactory results much of the time, but that visual inspection is necessary to guard against large errors.

Brain↗
PubMedDate not supplied

A new multislab 3D balanced turbo field echo technique for imaging of the renal arteries without contrast agent.

An 80-year-old female patient with arterial hypertension and slowly progressive deterioration of renal function was referred to our department for investigation of the renal arteries. Imaging of the renal arteries with ultrasound was inconclusive, due to obesity. Subsequently, imaging was performed with balanced turbo field echo which is a newly developed technique in our department. This new technique for the moment is still combined with contrast-enhanced magnetic resonance angiography. A therapeutic digital subtraction angiography was performed for stent placement.

Aged↗