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Biomedical subjects

F Haven

Publications and source records attributed to F Haven.

5 recordsLinked to original sources
PubMed2006

[Wernicke's encephalopathy associated with chronic disulfiram intoxication].

INTRODUCTION: We report the case of a patient with an unusual association of Wernicke encephalopathy and chronic disulfiram intoxication. CASE REPORT: A 41-year-old man presented with progressive frontal decline and akineto-rigid parkinsonism under chronic disulfiram therapy. He also developed acute confusion with ataxia, blepharospasm, and supranuclear ophthalmoplegia following a severe malnutrition due to refusal of food intake. Brain MRI revealed symmetrical and reversible hyperintense lesions on T2 and FLAIR in the posterior putaminal regions, dorso-medial thalamic and subthalamic nuclei, the periaqueducal gray matter, the cerebellar peduncles, and the pontine tegmentum. A slow partial clinical recovery with persistent frontal syndrome was observed after discontinuation of disulfiram and parenteral administration of thiamine. DISCUSSION: The symmetry and reversibility of the MRI lesions in the basal ganglia and brain stem were suggestive of a deficiency, a toxic or a metabolic neurological disease. The dorso-medial thalamo-subthalamic and brainstem localizations, as well as their occurrence in a state of malnutrition, were consistent with Wernicke encephalopathy. Moreover, chronic disulfiram intoxication might explain the frontal syndrome and the akineto-rigid parkinsonism, associated with MRI putaminal lesions. Similar MRI lesions have been described in the so-called "energy deprivation syndromes", which are toxic, genetic or nutritional disorders that disrupt enzymes involved in energy generating metabolic pathways such as glycolysis and pyruvate oxidation.

Adult↗
PubMed2001

Imaging characteristics of noncontained migrating disc fragment and cyst.

The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma.

Adult↗
PubMed1997

Evaluation of manual vs semi-automated delineation of liver lesions on CT images.

In this paper we compare a semi-automated delineation method with totally manual delineation for area quantification, with respect to efficiency, quality, and intra- and interobserver variability. Liver lesions on 28 CT images were delineated by three observers, twice using completely manual delineation and twice using a semi-automated method. Quantitative comparisons were performed with respect to delineated area and time required for the delineation tasks. Subjective comparisons were performed with respect to efficiency and perceived quality of the semi-automated method. The areas obtained using semi-automated delineation were significantly smaller (11 %) than those obtained using totally manual delineation. Intraobserver and interobserver variability with the semi-automated method were approximately three times lower than with manual delineation. Efficiency of the semi-automated method was subjectively rated favorable, although further improvements are possible. With respect to quality, the semi-automated method was ranked better than the manual method in 73 % of cases.

Humans↗
PubMedDate not supplied

Factors influencing the accuracy of volume measurements in spiral CT: a phantom study.

PURPOSE: The purpose of this study was to investigate the influence of different parameters (object size, shape, orientation, contrast, observer, and window setting) on the accuracy of volume measurements in spiral CT. METHOD: The phantom study consisted of two parts. First, well-circumscribed ellipsoid objects were scanned with conventional and spiral CT. Volumes were determined by two observers using manual contour delineation and summation-of-areas. The influence of object size, CT technique, and observer was assessed. Second, irregularly shaped gingerroots were scanned and the effect of observer, contrast, and orientation was investigated. Also assessed in both parts of the study was the effect of window setting. RESULTS: Spiral CT offered higher accuracy and reproducibility than conventional CT did. The accuracy of volume measurements was mainly determined by the window setting used for image display. Using an "optimized" window center value halfway between object density and background density resulted in overestimation of true object volumes if the number of slices through the object (number of samples) was low. Other factors (contrast, observer-related errors in contour delineation) were less important. CONCLUSIONS: Volume measurements of small objects, obtained with spiral CT and using manual contour delineation, may be grossly erroneous. Major causes of inaccuracy are an inappropriate window center selection and undersampling.

Phantoms, Imaging↗