Browsing by Author "Diaz, Violeta"

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    Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography
    (2023) Cheng, Kevin; Lin, Andrew; Stecher, Ximena; Bernstein, Tomas; Zuniga, Paulo; Mazzon, Enrico; Brunser, Alejandro; Diaz, Violeta; Martinez, Gonzalo; Cameron, William; Nicholls, Stephen J.; Patel, Sanjay; Dey, Damini; Wong, Dennis T. L.; Venturelli, Paula Munoz
    Background: Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. Objectives: We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVAT(carotid)) with and without spontaneous dissection. Methods: Single-center prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA). Of these patients, six underwent follow-up computed tomography angiography (CTA). Twenty-two patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semi-automated research software, PVAT(carotid) was measured as the mean Hounsfield unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. Results: PVAT(carotid) was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (-58.7 +/- 10.2 vs -68.9 +/- 8.1 HU, p < 0.0001) and ICA of patients without dissection (-58.7 +/- 10.2 vs -69.3 +/- 9.3 HU, p < 0.0001). After a median follow-up of 89 days, there was a significant reduction in PVAT(carotid) around dissected ICA (-57.5 +/- 13.4 to -74.3 +/- 10.5 HU, p < 0.05), while no change was observed around non-dissected contralateral ICA (-71.0 +/- 4.4 to -74.1 +/- 4.1 HU, p = 0.19). ICA dissection was an independent predictor of PVAT(carotid) following multivariable adjustment for age and the presence of ICA occlusion. Conclusion: PVAT(carotid) is elevated in the presence of sCAD and may decrease following the acute event.
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    Cryptococcus bacillisporus (VGIII) Meningoencephalitis Acquired in Santa Cruz, Bolivia
    (2021) Thompson, Luis; Porte, Lorena; Diaz, Violeta; Diaz, Maria Cristina; Solar, Sebastian; Valenzuela, Pablo; Norley, Nicole; Pires, Yumai; Carreno, Fernando; Valenzuela, Sergio; Shabani, Rukmane; Rickerts, Volker; Weitzel, Thomas
    We describe a case of chronic meningoencephalitis with hydrocephalus caused by Cryptococcus bacillisporus (VGIII) in an immunocompetent patient from Santa Cruz, Bolivia. This first report of a member of the Cryptococcus gattii species complex from Bolivia suggests that C. bacillisporus (VGIII) is present in this tropical region of the country and complements our epidemiological and clinical knowledge of this group of emerging fungal pathogens in South America.