Browsing by Author "Meneses, Luis"
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- ItemCarotid artery dissection: Endovascular treatment. Report of 12 patients(WILEY-LISS, 2008) Fava, Mario; Meneses, Luis; Loyola, Soledad; Tevah, Jose; Bertoni, Hernan; Huetel, Isidro; Mellado, PatricioObjective: The purpose of this article is to report our experience with endovascular treatment of internal carotid artery (ICA) dissection with the use of stents. Background: Carotid Dissection is an important cause of ischemic stroke in young and middle-aged patients. There are some patients in whom invasive management is recommended. Methods: Twelve patients (eight females, four males), mean age of 50 years (range 3580 years) with ICA dissection, were treated with the endovascular approach during a 24-month period. Patients included in this study underwent magnetic resonance (MR) and digital subtraction angiography (DSA) for diagnosis. Over this time period, 162 patients with ICA dissections were seen at our institution. Indications for endovascular treatment were: recurrent ischemic events despite adequate anticoagulant treatment in seven cases, contraindication to anticoagulation in four cases, and one case with significant mismatch between diffusion and perfusion weighted MR. Eleven dissections were spontaneous and one was traumatic. The follow-up was performed clinically with Doppler ultrasound (US) and MR at 6, 12, and 24 months. Results: Stent deployment was successful in all cases. Acute symptoms were resolved in 66.7% of patients. No patients deteriorated their neurological status. There were no new clinical events, stent stenosis or occlusion on 24 months follow-up. Conclusion: Our results showed an excellent clinical outcome of the treated patients. This suggests promising results with the use of endovascular treatment in selected patients. (c) 2008 Wiley-Liss, Inc.
- ItemEnhancement of Visual Perception with Use of Dynamic Cues(RADIOLOGICAL SOC NORTH AMERICA, 2009) Andia, Marcelo E.; Plett, Johannes; Tejos, Cristian; Guarini, Marcelo W.; Navarro, Maria E.; Razmilic, Dravna; Meneses, Luis; Villalon, Manuel J.; Irarrazaval, PabloInstitutional review board approval and signed informed consent were not needed, as medical images included in public databases were used in this study. The purpose of this study was to improve the detection of microcalcifications on mammograms and lung nodules on chest radiographs by using the dynamic cues algorithm and the motion and flickering sensitivity of the human visual system (HVS). Different sets of mammograms from the Mammographic Image Analysis Society database and chest radiographs from the Japanese Society of Radiological Technology database were presented statically, as is standard, and in a video sequence generated with the dynamic cues algorithm. Nine observers were asked to rate the presence of abnormalities with a five-point scale (1, definitely not present; 5, definitely present). The data were analyzed with receiver operating characteristic (ROC) techniques and the Dorfman-Berbaum-Metz method. The video sequence generated with the dynamic cues algorithm increased the rate of detection of microcalcifications by 10.2% (P = .002) compared with that obtained with the standard static method, as measured by the area under the ROC curve. Similar results were obtained for lung nodules, with an increase of 12.3% (P = .0054). The increase in the rate of correct detection did not come just from the image contrast change produced by the algorithm but also from the fact that image frames generated with the dynamic cues algorithm were put together in a video sequence so that the motion sensitivity of the HVS could be used to facilitate the detection of low-contrast objects. (C) RSNA, 2009
- ItemMyocardial lipids and creatine measured by magnetic resonance spectroscopy among patients with heart failure(SOC MEDICA SANTIAGO, 2010) Luis Winter, Jose; Castro, Pablo; Meneses, Luis; Chalhub, Monica; Verdejo, Hugo; Greig, Douglas; Gabrielli, Luigi; Chiong, Mario; Concepcion, Roberto; Mellado, Rosemarie; Hernandez, Claudia; Uribe, Sergio; Lavander, SergioBackground: Heart failure (HF) is characterized, among other features, by the development of alterations in myocardial energy metabolism, involving a decrease in glucose utilization and increased free fatty acid uptake by cardiomyocytes, associated with decreased deposits of high-energy phosphates (creatine phosphate/ creatine transporter). Magnetic resonance (MR) imaging allows a direct and noninvasive assessment of myocardial metabolites. Aim: To measure myocardial creatine and lipids by MR spectroscopy among patients with HE Material and Methods: Cardiac MR spectroscopy (1.5 Tesla) with Hydrogen antenna and single voxel acquisition was performed in five patients with non-ischemic heart failure, aged 58 +/- 9.7 years, (60% males) and 5 healthy volunteers matched for age and sex. We analyzed the signals of creatine (Cr), lipids (L) and water (W) in the interventricular septum, establishing the water/lipid (W/L) and water/creatine (W/Cr) index to normalize the values obtained. Results: Among patients, left ventricular ejection fraction was 32 +/- 6.9%, 60% were in functional capacity II, 60% had hypertension and one was diabetic. Spectroscopic curves showed a depletion of total Cr, evidenced by the W/Cr index, among patients with heart failure, when compared with healthy controls (1.46 +/- 1.21 and 5.96 +/- 2.25 respectively, p < 0,05). Differences in myocardial lipid content, measured as the W/L index, were not significant (5.06 +/- 2.66 and 1.80 +/- 1.62 respectively, p = 0.08). Conclusions: Among patients with heart failure of non-ischemic etiology, there is a depletion of creatine levels measured by MR spectroscopy. (Rev Med Chile 2010; 138: 1475-1479).