Biomedical subjects

S España

Publications and source records attributed to S España.

3 recordsLinked to original sources

PubMed2006

FIRST: Fast Iterative Reconstruction Software for (PET) tomography.

Small animal PET scanners require high spatial resolution and good sensitivity. To reconstruct high-resolution images in 3D-PET, iterative methods, such as OSEM, are superior to analytical reconstruction algorithms, although their high computational cost is still a serious drawback. The higher performance of modern computers could make iterative image reconstruction fast enough to be viable, provided we are able to deal with the large number of probability coefficients for the system response matrix in high-resolution PET scanners, which is a difficult task that prevents the algorithms from reaching peak computing performance. Considering all possible axial and in-plane symmetries, as well as certain quasi-symmetries, we have been able to reduce the memory requirements to store the system response matrix (SRM) well below 1 GB, which allows us to keep the whole response matrix of the system inside RAM of ordinary industry-standard computers, so that the reconstruction algorithm can achieve near peak performance. The elements of the SRM are stored as cubic spline profiles and matched to voxel size during reconstruction. In this way, the advantages of 'on-the-fly' calculation and of fully stored SRM are combined. The on-the-fly part of the calculation (matching the profile functions to voxel size) of the SRM accounts for 10-30% of the reconstruction time, depending on the number of voxels chosen. We tested our approach with real data from a commercial small animal PET scanner. The results (image quality and reconstruction time) show that the proposed technique is a feasible solution.

Algorithms↗

PubMed2006

[Scurvy and acquired ichthyosis associated to Whipple's disease].

The skin manifestations, except for hyperpigmentation, are uncommon in Whipple's disease (WD). We present the case of a 48-year-old male with chronic diarrhea and long course general syndrome associated to neurological manifestations. Skin examination revealed lesions in the lower limbs and gums that were clinically consistent with scurvy and were confirmed by histological study and measurement of blood vitamin C levels. Furthermore, he had lesions that were clinically and histologically consistent with acquired ichthyosis. The digestive tract biopsy study showed non-necrotizing epithelioid granulomas without the presence of PAS positive macrophages. The patient was diagnosed of Whipple's disease through the identification of genomic fragments of Tropheryma Whippelii by PCR in duodenal samples. He was treated with antibiotics for two years with resolution of the cutaneous and digestive picture but with partial improvement of the neurological symptoms. In the literature reviewed, we did not find any case of acquired ichthyosis associated to WD and only one of scurvy secondary to this rare disease.

Anti-Bacterial Agents↗

PubMed2006

[Necrobiotic xanthogranuloma with scleroatrophic lichen associated with paraproteinemia].

Necrobiotic xanthogranuloma (Xn) with paraproteinemia is a histiocytoxanthomatosis (non-X histiocytosis) that affects the dermis and subcutaneous tissue of the face and less frequently the trunk and limbs. We present the case of a 58-year-old woman with a previous background of IgG (lambda) paraproteinemia and multiple autoimmune diseases, that associate clinically and histologically typical lesions of Xn on face, neck and limbs and of lichen sclerosus et atrophius (LEA) on skin and mucosae. The treatments performed were ineffective, the Xn lesions followed a chronic and progressive course with increased number, size and ulceration of them. The paraproteinemia has remained stable since it was diagnosed eight years ago. We have not found the association of Xn with paraproteinemia and SAL described in the literature. We review the characteristics of this rare disease and its possible pathogenic mechanisms.

Female↗