LUCAS RAMOS DE PRETTO

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Relationship between nonperfusion area from widefeld optical coherence tomography angiography and macular vascular parameters in diabetic retinopathy
2023 - KONNO, AMI; ISHIBAZAWA, AKIHIRO; PRETTO, LUCAS de; SHIMOUCHI, AKITO; OMAE, TSUNEAKI; SONG, YOUNG‑SEOK
Purpose To evaluate the relationship between the nonperfusion area (NPA) from widefield optical coherence tomography angiography (OCTA) and macular vascular parameters in diabetic retinopathy (DR). Methods In total, 51 eyes from 51 patients with proliferative DR (PDR) or moderate/severe non-PDR were included. Widefield OCTA using the Zeiss Plex Elite 9000 was performed. A semi-automatic algorithm calculated the percentages of the NPA within the total image. Macular OCTA (3 × 3 mm and 6 × 6 mm area) was scanned using the RTVue-XR Avanti. Vessel density (VD) was automatically separated into the superficial (SCP) and deep capillary plexus (DCP), and foveal avascular zone (FAZ) measurements were computed according to the parafoveal (1–3 mm) and perifoveal (3–6 mm) regions. Results A negative correlation was found between the average VD of the SCP and DCP obtained 3 × 3 mm and 6 × 6 mm area and the NPA. Multiple regression analysis revealed that the temporal–perifoveal region most negatively correlated with the NPA (r = − 0.55, p < 0.0001). No correlation was found between FAZ measurements and DR severity (area, p = 0.07; perimeter, p = 0.13). Conclusion Diabetic macular nonperfusion was significantly associated with the NPA from widefield OCTA. In particular, the temporal–perifoveal DCP disorder may be a sensitive indicator of wide NPA.
Noninvasive red Laser intervention before radiotherapy of triple-negative breast cancer in a murine model
2023 - SILVA, CAMILA R.; PEREIRA, SAULO T.; SILVA, DANIELA F.T.; PRETTO, LUCAS R. de; FREITAS, ANDERSON Z.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.; RIBEIRO, MARTHA S.
In proton beam treatments, the superposition of several weighted Bragg curves with different incident energies is required to homogeneously irradiate a large tumor volume, creating a spread-out Bragg peak (SOBP). This paper confirms on the suitability of two different methods to create SOBPs – Bortfeld/Jette's and MCMC (Monte Carlo calculations and Matrix Computations), using Monte Carlo simulations performed with TOPAS and MCNP6.1. To generate the SOBPs, algorithms were developed for implementation of the two methods, which enabled to find the weights for thirty variations of SOBPs, categorized according to their width and maximum depths. The MCMC method used weight optimization in designing SOBPs to avoid negative values. In contrast, the Bortfeld/Jette's method yielded the SOBPs according to the variation of a power-law parameter ( ) introduced by the range-energy relationship. Optimal values of , from MCNP and TOPAS, were selected in order to retrieve SOBPs with the best smoothness and then related to those obtained from the literature. In comparing both methods and codes, dose homogeneity parameters ( ) were used to examine the SOBP flatness and gamma analyses were employed to assess the dose deposition along its full extension. The results showed that the SOBPs designed using the MCMC method had better values and computational performance for both codes when compared to the Bortfeld/Jette's method. The gamma analyses highlighted significant differences between the entrance doses comparing the two different methods, for SOBPs with intermediate and high depths and small width. This evaluation was not possible with the values alone, which stresses the relevance of a broad analysis to avoid unintended doses in healthy tissues.
Optical coherence tomography (OCT) for the analysis of zirconia crystalline phase transformation
2023 - ARATA FOUND, ANELYSE; PRETTO, L.R. de; USSUI, V.; LIMA, N.B. de; SOUZA, G.M. de; MACHADO, J.P.B.; TANGO, R.N.; FREITAS, A.Z.; LAZAR, D.R.R.
This study aimed to validate the Optical coherence tomography (OCT) for the analysis of the transformed zone of two dental zirconia-based materials after hydrothermal ageing and correlate the values with biaxial flexural strength. Kinetics of tetragonal to monoclinic phase transformation (t→m) was calculated. X-ray diffraction (XRD) results showed a sigmoidal transformation rate over time due to the limited X-ray maximum penetration depth. Scanning electron microscope (SEM) and OCT showed a linear relationship between the thickness of the transformed layer and the ageing time. The apparent activation energy was 104.5 kJ/mol and 106.7 kJ/mol (SEM) and 106 kJ/mol and 99.4 kJ/mol (OCT) for the infrastructure and monolithic dental zirconia, respectively. Mechanical strength decreased after 150 h. of ageing at 150 ◦C for both materials showing a correlation with the depth of the transformed zone observed by OCT. Therefore, both monoclinic phase percentage and the depth of the transformed layer are critical concerning zirconia mechanical properties upon hydrothermal ageing. OCT is a non-destructive, fast, innovative, and accurate method for the analysis of zirconia’s t→m phase transformation depth kinetics after hydrothermal ageing.
Long-term functioning status of COVID-19 survivors
2022 - BATTISTELLA, LINAMARA R.; IMAMURA, MARTA; DE PRETTO, LUCAS R.; VAN CAUWENBERGH, SIMON K.H.A.A.; RAMOS, VINICIUS D.; UCHIYAMA, SABRINA S.T.; MATHEUS, DENISE; KUHN, FLAVIA; OLIVEIRA, ANA A.A. de; NAVES, GABRIELLA S.; MIRISOLA, ALINE R.; RIBEIRO, FERNANDO de Q.; SUGAWARA, ANDRE T.; CANTARINO, MAURICIO; CAVALCA, RAFAEL A.S.A.; PAGANO, VANESSA; MARQUES, MELINA V.; SILVA, ELIZABETH M. da; GOMES, ALESSANDRA P.; FREGNI, FELIPE
Objectives The study investigated the long-term functional status of hospitalised COVID-19 survivors to explore and document their functional situation. Design This prospective observational study assessed 801 COVID-19 survivors at 3–11 months after hospital discharge. It analyses participants' sociodemographic background, COVID-19 clinical manifestations, and clinical and functional evaluations. Setting Tertiary-level university hospital in São Paulo, Brazil. Participants Study participants are COVID-19 survivors admitted to hospital care for at least 24 hours to treat acute SARS-CoV-2 infection. Outcome measures Epworth Sleepiness Scale, EuroQoL-5 Dimensions-5 Levels, Functional Assessment of Chronic Illness Therapy–Fatigue, Functional Independence Measure, Functional Oral Intake Scale, Handgrip Strength, Insomnia Severity Index, Medical Research Council (MRC) Dyspnea Scale, MRC sum score, Modified Borg Dyspnea Scale, pain Visual Analogue Scale, Post-COVID-19 Functional Status, Timed Up and Go, WHO Disability Assessment Schedule 2.0, 1-Minute Sit to Stand Test. Results Many participants required invasive mechanical ventilation (41.57%, 333 of 801). Mean age was 55.35±14.58 years. With a mean of 6.56 (SD: 1.58; 95% CI: 6.45 to 6.67) months after hospital discharge, 70.86% (567 of 800) reported limited daily activities, which were severe in 5.62% (45 of 800). They also reported pain and discomfort (64.50%, 516 of 800), breathlessness (64.66%, 514 of 795), and anxiety and depression (57.27%, 457 of 798). Daytime sleepiness and insomnia evaluations showed subthreshold results. Most (92.85%, 727 of 783) participants reported unrestricted oral intake. Data indicated no generalised fatigue (mean score: 39.18, SD: 9.77; 95% CI: 38.50 to 39.86). Assessments showed poor handgrip strength (52.20%, 379 of 726) and abnormal Timed Up and Go results (mean 13.07 s, SD: 6.49). The invasive mechanical ventilation group seemed to have a better handgrip strength however. We found no clear trends of change in their functional status during months passed since hospital discharge. Conclusions Muscle weakness, pain, anxiety, depression, breathlessness, reduced mobility, insomnia and daytime sleepiness were the most prevalent long-term conditions identified among previously hospitalised COVID-19 survivors.
Rehabilitation of patients after COVID-19 recovery
2021 - IMAMURA, MARTA; MIRISOLA, ALINE R.; RIBEIRO, FERNANDO de Q.; DE PRETTO, LUCAS R.; ALFIERI, FABIO M.; DELGADO, VINICIUS R.; BATTISTELLA, LINAMARA R.
OBJECTIVES: As patients recovering from the novel coronavirus disease 2019 (COVID-19) present with physical, respiratory, cognitive, nutritional, and swallowing-related impairments and mental health complications, their rehabilitation needs are complex. This study aimed to describe the demographic, clinical, and functional status after the discharge of COVID-19 survivors who underwent intensive multidisciplinary inpatient rehabilitation at the Physical and Rehabilitation Medicine Institute of the University of Sao Paulo Medical School General Hospital and Lucy Montoro Rehabilitation Institute. We determined the most important factors related to the length of inpatient rehabilitation treatment and present the functional outcomes. METHODS: This was a retrospective study based on electronic medical records. In addition to the severity of COVID-19 and length of hospital stay for the management of COVID-19 and comorbidities, we collected sociodemographic data including age, sex, height, and weight. Functional assessments were performed using the Functional Independence Measure (FIM); Short Physical Performance Battery; Montreal Cognitive Assessment; Depression, Anxiety and Stress Scale; Revised Impact of Events Scale; bioelectrical impedance; Functional Oral Intake Scale; oropharyngeal dysphagia classification; and nutritional assessment. RESULTS: There was a significant improvement in FIM before and after inpatient rehabilitation treatment (p<0.0001). Muscle strength and walking capacity were significantly improved (p<0.01). The most important factors related to the length of inpatient rehabilitation treatment were improvement in FIM scores (Spearman’s r=0.71) and gain in lean mass (Spearman’s r=0.79). CONCLUSIONS: Rehabilitation of patients after COVID-19 recovery improves their functional status and should be considered in the post-acute phase for selected patients with COVID-19.
Nondestructive evaluation of fused filament fabrication 3D printed structures using optical coherence tomography
2020 - DE PRETTO, LUCAS R.; AMARAL, MARCELO M.; FREITAS, ANDERSON Z. de; RAELE, MARCUS P.
Purpose – The quality of components under fused filament fabrication (FFF) is related to the correct filament spacing and bonding of successively deposited layers and is evaluated mainly by scanning electron microscopy (SEM). However, it is a destructive technique and real-time evaluation is not possible. Optical coherence tomography (OCT), on the other hand, is an optical method that acquires cross-sectional images non-invasively and in real-time. Therefore, this paper aims to propose and validate the use of OCT as a non-destructive quality evaluation tool for FFF using Polylactic Acid (PLA) filaments. Design/methodology/approach – PLA three-dimensional (3D) printed samples were made in a variety of nozzle temperatures and mesh spacing. These samples were fractured in liquid nitrogen and inspected using SEM (as a gold standard) to evaluate dimensions and morphology, then the samples were evaluated by OCT in the same area, allowing the results confrontation. Findings – Our results indicate a good correlation between OCT and SEM for the dimensional assessment of layers. When the filament was extruded in lower temperatures, the OCT images presented sharply defined interfaces between layers, in contrary to higher nozzle temperatures, denoting better fusion between them. However, higher extruding temperatures are incurred in greater deviations from nominal dimensions of the mesh. Finally, we demonstrate the advantage of a full 3D tomographic reconstruction to inspect within a FFF sample, which enabled the inspection of “hidden” information, not visible on a single cross-sectional cut. Originality/value – This paper proposes OCT as a novel and nondestructive evaluation tool for FFF.
Osteoporosis evaluation through full developed speckle imaging
2020 - AMARAL, MARCELLO M.; DEL-VALLE, MATHEUS; RAELE, MARCUS P.; DE PRETTO, LUCAS R.; ANA, PATRICIA A.
Osteoporosis is a disease characterized by bone mineral density reduction, weakening the bone structure. Its diagnosis is performed using ionizing radiation, increasing health risk. Optical techniques are safer, due to non-ionizing radiation use, but limited to the analyses of bone tissue. This limitation may be circumvented in the oral cavity. In this work we explored the use of laser speckle imaging (LSI) to differentiate the sound and osteoporotic maxilla andmandible bones in an in vitro model. Osteoporosis lesions were simulated with acid attack. The samples were evaluated by optical profilometry and LSI, using a custom software. Two image parameters were evaluated, speckle contrast ration and patches ratio. With the speckle contrast ratio, it was possible to differentiate sound from osteoporotic tissue. From speckle patches ratio it was observed a negative correlation with the roughness parameter. LSI is a promissory technique for assessment of osteoporosis lesions on alveolar bone.
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.
Retinal nonperfusion relationship to arteries or veins observed on widefield optical coherence tomography angiography in diabetic retinopathy
2019 - ISHIBAZAWA, AKIHIRO; PRETTO, LUCAS R. de; ALIBHAI, A. YASIN; MOULT, ERIC M.; ARYA, MALVIKA; SOROUR, OSAMA; MEHTA, NIHAAL; BAUMAL, CAROLINE R.; WITKIN, ANDRE J.; YOSHIDA, AKITOSHI; DUKER, JAY S.; FUJIMOTO, JAMES G.; WAHEED, NADIA K.
PURPOSE. To evaluate whether retinal capillary nonperfusion is found predominantly adjacent to arteries or veins in eyes with diabetic retinopathy (DR). METHODS. Sixty-three eyes from 44 patients with proliferative DR (PDR) or non-PDR (NPDR) were included. Images (12 3 12-mm) foveal-centered optical coherence tomography (OCT) angiography (OCTA) images were taken using the Zeiss Plex Elite 9000. In 37 eyes, widefield montages with five fixation points were also obtained. A semiautomatic algorithm that detects nonperfusion in full-retina OCT slabs was developed, and the percentages of capillary nonperfusion within the total image area were calculated. Retinal arteries and veins were manually traced. Based on the shortest distance, nonperfusion pixels were labeled as either arterial-side or venous-side. Arterial-adjacent and venous-adjacent nonperfusion and the A/V ratio (arterial-adjacent nonperfusion divided by venous-adjacent nonperfusion) were quantified. RESULTS. Twenty-two eyes with moderate NPDR, 16 eyes with severe NPDR, and 25 eyes with PDR were scanned. Total nonperfusion area in PDR (median: 8.93%) was greater than in moderate NPDR (3.49%, P < 0.01). Arterial-adjacent nonperfusion was greater than venousadjacent nonperfusion for all stages of DR (P < 0.001). The median A/V ratios were 1.93 in moderate NPDR, 1.84 in severe NPDR, and 1.78 in PDR. The A/V ratio was negatively correlated with the total nonperfusion area (r ¼ 0.600, P < 0.0001). The results from the widefield montages showed similar patterns. CONCLUSIONS. OCTA images with arteries and veins traced allowed us to estimate the nonperfusion distribution. In DR, smaller nonperfusion tends to be arterial-adjacent, while larger nonperfusion tends toward veins.
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.