Anatomical Localization (anatomical + localization)

Distribution by Scientific Domains

Selected Abstracts

3 Tesla and 7 Tesla MRI of multiple sclerosis cortical lesions

Emma C. Tallantyre BM
Abstract Cortical lesions are prevalent in multiple sclerosis but are poorly detected using MRI. The double inversion recovery (DIR) sequence is increasingly used to explore the clinical relevance of cortical demyelination. Here we evaluate the agreement between imaging sequences at 3 Tesla (T) and 7T for the presence and appearance of individual multiple sclerosis cortical lesions. Eleven patients with demyelinating disease and eight healthy volunteers underwent MR imaging at 3T (fluid attenuated inversion recovery [FLAIR], DIR, and T1 -weighted magnetization prepared rapid acquisition gradient echo [MP-RAGE] sequences) and 7T (T1 -weighted MP-RAGE). There was good agreement between images for the presence of mixed cortical lesions (involving both gray and white matter). However, agreement between imaging sequences was less good for purely intracortical lesions. Even after retrospective analysis, 25% of cortical lesions could only be visualized on a single MRI sequence. Several DIR hyperintensities thought to represent cortical lesions were found to correspond to signal arising from extracortical blood vessels. High-resolution 7T imaging appeared useful for confidently classifying the location of lesions in relation to the cortical/subcortical boundary. We conclude that DIR, FLAIR, and MP-RAGE imaging sequences appear to provide complementary information during the detection of multiple sclerosis cortical lesions. High resolution 7T imaging may facilitate anatomical localization of lesions in relation to the cortical boundary. J. Magn. Reson. Imaging 2010;32:971,977. 2010 Wiley-Liss, Inc. [source]

Virus-specific CD8 T cells: activation, differentiation and memory formation

APMIS, Issue 5-6 2009
CD8 T cells are pivotal for the control of many intracellular pathogens, and besides their role in immediate control of infections, CD8 T cells have the capacity to differentiate into long-lived antigen-independent memory CD8 T cells, at least in situations of acute and resolved infections. The population of memory cells is heterogeneous with respect to their phenotype, their anatomical localization and their functional capacities in order to afford optimal protection against secondary infections. In the past years, it has become clear that multiple in vivo parameters are involved in shaping the composition of the memory CD8 T cell population, including antigen load, duration and strength of CD8 T cell stimulation, the level of inflammation, availability of CD4 T cell help and CD8 T cell precursor frequencies. With respect to the timing when CD8 T cells are committed to become memory cells, several models have been proposed. In contrast to acute, resolved infection, the continued in vivo exposure to high levels of antigen during persistent chronic viral infection precludes the development of long-lived antigen-independent memory CD8 T cells and might even result in severe dysfunction of virus-specific CD8 T cells. [source]

Pure Sensory Stroke as an Isolated Manifestation of the Lateral Medullary Infarction

Svetlana Blitshteyn MD
ABSTRACT Pure sensory stroke is a common manifestation of a thalamic stroke and may occur less frequently in the infarction of the brainstem, internal capsule, and parietal cortex. The authors report a 47-year-old man who presented with loss of pain and temperature sensation in the left face, arm, trunk, and leg and was found to have a right lateral medullary infarction on diffusion-weighted magnetic resonance imaging. To the authors' knowledge, this is the first case describing pure sensory stroke as a single, isolated manifestation of the lateral medullary infarction that was detected by diffusion-weighted magnetic resonance imaging. This case suggests that with the availability of diffusion-weighted magnetic resonance imaging, pure sensory stroke may carry a broader spectrum of the anatomical localizations than previously determined and can localize to the lateral medulla. Therefore, a possibility of medullary infarction should be considered when a patient presents with pure sensory stroke, especially when diffusion-weighted magnetic resonance imaging is not immediately available to provide radiographic correlation. [source]

Vitiligo and ocular findings: a study on possible associations

E Bulbul Baskan
Abstract Objective, In this study, we aimed to evaluate the ocular findings in vitiligo patients and reveal any clinical feature that might suggest an association or a risk factor. Background, Very few reports in the literature are available about the ocular findings in vitiligo and the possible associations of the ocular findings in vitiligo patients have not been studied so far. Methods, A total of 45 patients with previously documented cutaneous vitiligo were examined for ocular findings. Demographic features including age, gender, duration of vitiligo, presence of associated autoimmune diseases, type of vitiligo and the anatomical distributions of vitiligo were recorded to evaluate a possible relationship with the ocular findings. Univariate and multivariate analyses as well as cluster analysis were performed. After description of the clusters, the Mann,Whitney U -test and Fisher's exact test were used to determine the variables. Concordance among the variables in each group was evaluated with the McNemar test. Results, Ten patients had ocular findings that included anterior segment (iris) involvement, ring-like peripapillary atrophy around the optic nerve, atrophy of pigment epithelium, focal hypopigmented spots and diffuse hypopigmentation. The presence of periorbital vitiligo was significantly related to the ocular findings. Cluster analysis revealed concordances between periorbital and genitalial localizations of vitiligo and ocular findings. Conclusion, The number of patients and the range of ocular findings in our study are insufficient to make definite conclusions but anatomical localizations, primarily periorbital and to a lesser extent genitalial vitiligo, seem to be the most probably alerting features for ocular findings. [source]