On the quantitative analysis of lamellar collagen arrangement with second-harmonic generation imaging.

Second harmonic generation (SHG) allows for the examination of collagen structure in collagenous tissues. Collagen is a fibrous protein found in abundance in the human body, present in bones, cartilage, the skin, and the cornea, among other areas, providing structure, support, and strength. Its structural arrangement is deeply intertwined with its function. For instance, in the cornea, alterations in collagen organization can result in severe visual impairments. Using SHG imaging, various metrics have demonstrated the potential to study collagen organization. The discrimination between healthy, keratoconus, and crosslinked corneas, assessment of injured tendons, or the characterization of breast and ovarian tumorous tissue have been demonstrated. Nevertheless, these metrics have not yet been objectively evaluated or compared. A total of five metrics were identified and implemented from the literature, and an additional approach adapted from texture analysis was proposed. In this study, we analyzed their effectiveness on a ground-truth set of artificially generated fibrous images. Our investigation provides the first comprehensive assessment of the performance of multiple metrics, identifying both the strengths and weaknesses of each approach and providing valuable insights for future applications of SHG imaging in medical diagnostics and research.

Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study.

BACKGROUND: Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy. METHODS: The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters. ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation. The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study. DISCUSSION: The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04461912 , registered on July 8, 2020.

Effectiveness of exercise training on cancer-related fatigue in colorectal cancer survivors: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE: To investigate the effects of exercise training on cancer-related fatigue (CRF) in colorectal cancer survivors. METHODS: Randomized controlled trials published between 1 January 2010 and 19 October 2020, selected through online search conducted in PubMed, Scopus, Web of Science, SPORTDiscus and PEDro databases, were included. Eligible trials compared the effect of exercise training interventions, versus non-exercise controls on CRF, in colorectal cancer survivors, during or after treatment. The methodological quality of individual studies was analysed using the Physiotherapy Evidence Database (PEDro) scale. Standardized mean differences (SMD) that were pooled using random-effects models were included as the effect size. In addition, 95% prediction intervals (PI) were calculated. RESULTS: Six trials involving 330 colorectal cancer patients met the inclusion criteria and presented reasonable to good methodological quality. An overall small-to-moderate effect of exercise training on CRF was found (SMD = - 0.29: 95% CI: [- 0.53; - 0.06]; p = 0.01; PI: [- 0.63; 0.04]; low-quality evidence). Subgroup analysis revealed moderate effects of exercise interventions performed during chemotherapy (SMD = - 0.63; 95% CI: [- 1.06; - 0.21]; p = 0.003) and small, non-significant effects, when exercise training was performed after cancer treatment (SMD = - 0.14; 95% CI: [- 0.43; 0.14]; p = 0.32). Steady improvements were achieved when a combination of aerobic plus resistance exercise was used, in interventions lasting 12 to 24 weeks. CONCLUSION: Exercise training could be regarded as a supportive therapy for the clinical management of CRF in colorectal cancer patients undergoing chemotherapy, but further studies are necessary to clarify the effects of exercise interventions on CRF after cancer treatment.

Simulation of cellular changes on Optical Coherence Tomography of human retina.

We present a methodology to assess cell level alterations on the human retina responsible for functional changes observable in the Optical Coherence Tomography data in healthy ageing and in disease conditions, in the absence of structural alterations. The methodology is based in a 3D multilayer Monte Carlo computational model of the human retina. The optical properties of each layer are obtained by solving the Maxwell's equations for 3D domains representative of small regions of those layers, using a Discontinuous Galerkin Finite Element Method (DG-FEM). Here we present the DG-FEM Maxwell 3D model and its validation against Mie's theory for spherical scatterers. We also present an application of our methodology to the assessment of cell level alterations responsible for the OCT data in Diabetic Macular Edema. It was possible to identify which alterations are responsible for the changes observed in the OCT scans of the diseased groups.