3 research outputs found

    Three-dimensional rotational angiography for craniotomy planning and postintervention evaluation of intracranial aneurysms

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    PURPOSE: The authors evaluated the usefulness of three-dimensional rotational angiography (3DRA) in surgical planning and postoperative evaluation of cerebral aneurysms. MATERIALS AND METHODS: A total of 111 consecutive aneurysms in 100 patients (32 emergency referrals due to haemorrhage) were evaluated with 3DRA over a period of 3 years. The rotational study was always performed with a single injection of 20 cc of contrast agent in the afferent vessel after diagnostic cerebral angiography in the two orthogonal projections. Three-dimensional reconstructions were obtained for the pre- and postoperative assessment. RESULTS: Three-dimensional RA provides a virtual view of the surgical field with the same orientation required for the surgical approach and, compared with surgical findings, reliably defined location, orientation, morphology and relationship with parent vessels of the aneurysm in all cases. Postoperatively, it allowed better assessment of any residual lesion and of the relationship between surgical clips and parent vessels, compared with standard 2D angiography. CONCLUSIONS: 3DRA is a reliable method for preliminary assessment of cerebral aneurysms undergoing surgery. It provides multiple projections with a preview of the surgical field and study of lesion characteristics, which can help achieve faster and safer surgery. Compared with 2D angiography, the 3D model, with its multiple views, allows better assessment of postoperative outcomes. The method also significantly reduces the number of angiographic projections and therefore radiation and contrast-medium dose to the patient

    Compression and knowledge discovery in ecology

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    A highly virulent variant of HIV-1 circulating in the Netherlands.

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    We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log <sub>10</sub> increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence
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