LUCAS RAMOS DE PRETTO

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2017 - 20203
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Agência de fomento: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) × Assunto: coherent radiation ×

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Agora exibindo 1 - 3 de 3
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    Artigo IPEN-doc 26892
    Quantification of retinal capillary nonperfusion in diabetics using wide-field optical coherence tomography angiography
    2020 - ALIBHAI, A.Y.; PRETTO, LUCAS R. de; MOULT, ERIC M.; OR, CHRIS; ARYA, MALVIKA; MCGOWAN, MITCHELL; CARRASCO-ZEVALLOS, OSCAR; LEE, BYUNGKUN; CHEN, SIYU; BAUMAL, CAROLINE R.; WITKIN, ANDRE J.; REICHEL, ELIAS; FREITAS, ANDERSON Z. de; DUKER, JAY S.; FUJIMOTO, JAMES G.; WAHEED, NADIA K.
    Purpose: To combine advances in high-speed, wide-field optical coherence tomography angiography (OCTA) with image processing methods for semiautomatic quantitative analysis of capillary nonperfusion in patients with diabetic retinopathy (DR). Methods: Sixty-eight diabetic patients (73 eyes), either without retinopathy or with different degrees of retinopathy, were prospectively recruited for volumetric swept-source OCTA imaging using 12 mm · 12 mm fields centered at the fovea. A custom, semiautomatic software algorithm was used to quantify areas of capillary nonperfusion. Results: The mean percentage of nonperfused area was 0.1% (95% confidence interval: 0.0–0.4) in the eyes without DR; 2.1% (95% confidence interval: 1.2–3.7) in the nonproliferative DR eyes (mild, moderate, and severe), and 8.5% (95% confidence interval: 5.0–14.3) in the proliferative DR eyes. The percentage of nonperfused area increased in a statistically significant manner from eyes without DR, to eyes with nonproliferative DR, to eyes with proliferative DR. Conclusion: Capillary nonperfusion area in the posterior retina increases with increasing DR severity as measured by swept-source OCTA. Quantitative analysis of retinal nonperfusion on wide-field OCTA may be useful for early detection and monitoring of disease in patients with diabetes and DR.
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    Artigo IPEN-doc 26419
    Controlling for artifacts in widefield optical coherence tomography angiography measurements of non-perfusion area
    2019 - PRETTO, LUCAS R. de; MOULT, ERIC M.; ALIBHAI, A.Y.; CARRASCO-ZEVALLOS, OSCAR M.; CHEN, SIYU; LEE, BYUNGKUN; WITKIN, ANDRE J.; BAUMAL, CAROLINE R.; REICHEL, ELIAS; FREITAS, ANDERSON Z. de; DUKER, JAY S.; WAHEED, NADIA K.; FUJIMOTO, JAMES G.
    The recent clinical adoption of optical coherence tomography (OCT) angiography (OCTA) has enabled non-invasive, volumetric visualization of ocular vasculature at micron-scale resolutions. Initially limited to 3 mm × 3 mm and 6 mm × 6 mm fields-of-view (FOV), commercial OCTA systems now offer 12 mm × 12 mm, or larger, imaging fields. While larger FOVs promise a more complete visualization of retinal disease, they also introduce new challenges to the accurate and reliable interpretation of OCTA data. In particular, because of vignetting, wide-field imaging increases occurrence of low-OCT-signal artifacts, which leads to thresholding and/or segmentation artifacts, complicating OCTA analysis. This study presents theoretical and case-based descriptions of the causes and effects of low-OCTsignal artifacts. Through these descriptions, we demonstrate that OCTA data interpretation can be ambiguous if performed without consulting corresponding OCT data. Furthermore, using wide-field non-perfusion analysis in diabetic retinopathy as a model widefield OCTA usage-case, we show how qualitative and quantitative analysis can be confounded by low-OCT-signal artifacts. Based on these results, we suggest methods and best-practices for preventing and managing low-OCT-signal artifacts, thereby reducing errors in OCTA quantitative analysis of non-perfusion and improving reproducibility. These methods promise to be especially important for longitudinal studies detecting progression and response to therapy.
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    Artigo IPEN-doc 23079
    Antimicrobial photodynamic therapy combined to periodontal treatment: experimental model
    2017 - BELINELLO-SOUZA, ESTEFANI L.; ALVARENGA, LETICIA H.; LIMA-LEAL, CINTIA; ALMEIDA, PATRICIA; LEITE, CAROLINA G.; LIMA, TAIRINE R.; GODOY-MIRANDA, BIANCA; PREVIATI-OLIVEIRA, JHOSEPHER; PRETTO, LUCAS de; FREITAS, ANDERSON Z. de; FERNANDES, ADJACI U.; MARCOS, RODRIGO L.; PRATES, RENATO A.
    tBackground: Antimicrobial photodynamic therapy (aPDT) has been used as an adjuvant treatment forperiodontitis. It combines a photosensitizer with a light source to induce reactive oxygen species and killmicrobial cells. PpNetNI is a protoporphyrin derivative, and it has a chemical binding site at biofilm andgreat affinity to microbial cells. The aim of this study was to investigate the effects of aPDT as an adjuvanttreatment for periodontitis.Methods: Thirty healthy male rats Wistar (Rattus norvegicus) were used in this study (Approved by UNI-NOVE Ethical committee AN0029/2015). Periodontitis was induced by placing a cotton ligature aroundthe first mandibular molar in a subgengival position. The contralateral mandibular first molar receivedneither a ligature nor any treatment, and was used as a control. After 7 days, the ligature was removedand all animals received scaling and root planing (SRP) and were divided according to the following treat-ments: SRP group (received SRP and irrigation with PpNetNI, 10 M) and aPDT group (PpNetNI 10 Mfollowed by LED irradiation). aPDT was performed with a LED (630 nm) with an output power of 400 mW(fluence-rate 200 mW/cm2; fluence 18 J/cm2). Rats were euthanized at 24 h, 48 h and 7 days postopera-tively. The area of bone loss in vestibular region of the first molar was evaluated by Optical CoherenceTomography (OCT, THORLABS LTD., Ely, UK). Data were analyzed statistically (ANOVA and Tukey tests,p < 0.05).Results: The animals treated by aPDT showed bone gain of approximately 30% compared to the SRP groupfollowing 7 days from the treatment.Conclusion: aPDT promoted bone recovery 7 days after periodontal intervention.