Navegando por Palavras-chave "Image interpretation, computer-assisted"
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- ItemAcesso aberto (Open Access)Diagnóstico auxiliado por computador na detecção de nódulos pulmonares pela tomografia computadorizada com múltiplos detectores: estudo preliminar de 24 casos(Sociedade Brasileira de Pneumologia e Tisiologia, 2008-01-01) Capobianco, Julia [UNIFESP]; Jasinowodolinski, Dany [UNIFESP]; Szarf, Gilberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Centro de Medicina Diagnóstica FleuryOBJECTIVES: To evaluate the performance of a computer program designed to facilitate the detection of pulmonary nodules using multidetector computed tomography (MDCT) scans of the chest. METHODS: We evaluated 24 consecutive MDCT scans of the chest at the Fleury Diagnostic Imaging Center during the period from October 7 to October 19 of 2006, using a 64-channel CT scanner. The study comprised 12 females and 12 males, ranging from 35 to 77 years of age (mean, 57.9 years). Double reading and a computer-aided diagnosis (CAD) system were used in order to perform two independent analyses of the data. The nodules found using both methods were recorded, and the data were compared. RESULTS: The total sensitivity of CAD for the detection of nodules was 16.5%, increasing to 55% when nodules <4 mm in diameter were excluded. Sensitivity by diameter was 6.5% for nodules <4 mm, 45% for nodules of 4-6 mm, 100% for nodules of 6 mm-10 cm, and 0% for nodules >1 cm. More than 99% of true nodules detected by CAD were registered in the image double reading process. CONCLUSIONS: In this preliminary 24-case study, the sensitivity of computer program tested was not significantly greater than that of the double-reading process that is routinely performed in this facility.
- ItemAcesso aberto (Open Access)Factors affecting the variability of the Heidelberg Retina Tomograph III measurements in newly diagnosed glaucoma patients(Conselho Brasileiro de Oftalmologia, 2010-08-01) Prata, Tiago dos Santos [UNIFESP]; Meira-Freitas, Daniel [UNIFESP]; Lima, Verônica Castro [UNIFESP]; Guedes, Lia Manis [UNIFESP]; Magalhães, Fernanda Pedreira [UNIFESP]; Paranhos Junior, Augusto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)PURPOSE: To determine factors associated with the test-retest variability of optic nerve head (ONH) topography measurements with confocal scanning laser ophthalmoscopy (CSLO) in newly diagnosed glaucomatous patients. METHODS: Consecutive patients with newly diagnosed primary open-angle glaucoma were prospectively enrolled. Patients presenting with any ocular disease other than glaucoma were excluded. All patients underwent CSLO using the Heidelberg Retina Tomograph III (HRT-III) in one randomly selected eye (three consecutive scans; performed by the same examiner). For each Heidelberg Retina Tomograph III parameter, repeatability was assessed using within subject standard deviation (Sw) and coefficient of variation (CVw), repeatability coefficient (RC) and intraclass correlation coefficient (ICC). Scatter plots and regression lines were constructed to identify which factors influenced test-retest measurement variability. RESULTS: A total of 32 patients were included (mean age, 65.4 ± 13.8 years). Most patients were female (65%) and white (50%). Among all Heidelberg Retina Tomograph III parameters evaluated, rim area and mean cup depth had the best measurement repeatability. Vertical cup-to-disc ratio (CDR, as determined by optic disc stereophotograph examination) was significantly associated (R²=0.21, p<0.01) with test-retest measurement variability. Eyes with larger CDR showed less variable measurements. Other factors, including age, disc area, central corneal thickness and intraocular pressure were not significant (p>0.14). CONCLUSION: Heidelberg Retina Tomograph III showed good test-retest repeatability for all ONH topographic measurements, mainly for rim area and mean cup depth. Test-retest repeatability seemed to improve with increasing CDR. These findings suggest that HRT-III topographic measurements should be cautiously interpreted when evaluating longitudinally glaucoma patients with early structural damage (small CDR).
- ItemSomente MetadadadosResultados preliminares de um algoritmo para ablação de lente de contato personalizada(Consel Brasil Oftalmologia, 2009-03-01) Matos, Luciana de [UNIFESP]; Carvalho, Luis Alberto Vieira de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Purpose: To develop a computer simulation for customized soft contact lenses in order to correct aberrations of higher order. Methods: Using real data from a patient diagnosed with keratoconus, which were measured using a Hartmann-Shack wavefront sensor, the thickness of the contact lenses that compensate these aberrations as well the numbers of pulses required to ablate the lenses were specifically determined for the patient. Results: The maps of correction are presented and the numbers of pulses are calculated, using a 0.5 mm beam width and a 0.3 mu m ablation depth. Conclusions: The results shown here are promising, but they should be improved so that the ablation in actual physical systems can reach the desired accuracy.