CycleGAN-Based Image to Image Translation for Realistic Surgical Training Phantoms.

Training in surgery is essential for surgeons to develop skill and dexterity. Physical training phantoms provide excellent haptic feedback and tissue properties for stitching and operating with authentic instruments and are easily available. However, they lack realistic traits and fail to reflect the complex environment of a surgical scene. Generative Adversarial Networks can be used for image-to-image translation, addressing the lack of realism in physical phantoms, by mapping patterns from the intraoperative domain onto the video stream captured during training with these surgical simulators. This work aims to achieve a successful I2I translation, from intra-operatory mitral valve surgery images onto a surgical simulator, using the CycleGAN model. Different experiments are performed - comparing the Mean Square Error Loss with the Binary Cross Entropy Loss; validating the Fréchet Inception Distance as a training and image quality metric; and studying the impact of input variability on the model performance. Differences between MSE and BCE are modest, with MSE being marginally more robust. The FID score proves to be very useful in identifying the best training epochs for the CycleGAN I2I translation architecture. Carefully selecting the input images can have a great impact in the end results. Using less style variability and input images with good feature details and clearly defined characteristics enables the network to achieve better results.Clinical Relevance- This work further contributes for the domain of realistic surgical training, successfully generating fake intra operatory images from a surgical simulator of the cardiac mitral valve.

Study of the compression behavior of functionally graded lattice for customized cranial remodeling orthosis.

Deformational plagiocephaly is a head deformity that occurs in newborns, treated in severe cases with helmets named cranial remodeling orthoses (CRO). Current CROs can fail to adapt to head growth, causing excessive pressure sores and other complications, and may lead to poor clinical results. In this work, we experimentally and numerically study the compressive behavior of a functionally graded lattice that may be used in future work as a potential inner lining for a CRO with a customized density distribution. This work is divided into five stages. First, we describe the design of all lattices involved in the study. Second, we measure the mechanical properties of the bulk material used in the manufacturing of the lattices. Third, we study the effect of unit cell size variation, testing three homogenous body-centered cubic (BCC) lattices, and creating a numerical model for the prediction of the compressive behavior of various lattices with different unit cell sizes. Fourth, we study the effects of truss diameter variation, designing and testing three homogenous lattices with different truss diameters. Finally, we design a BCC lattice with a truss diameter gradient and analyze compressive deformations in numerical and experimental compression studies. The numerical simulations of the compression of the homogenous and graded lattices agree with the experimental measurements, both in unit cell variation and in truss diameter variation. In the graded lattice, the compression displacements observed in each region are proportional to their density and agree with the numerical simulation. Truss diameter variation was found to have a wider range of compressive responses than unit cell size variation without major changes in the overall geometry of the lattice and found more suitable for the intended application. The studies showed the potential of the functionally graded lattice for use in the CRO.

Evaluation of spinal posture using Microsoft Kinect™: A preliminary case-study with 98 volunteers.

This work proposes a novel approach to assess spinal curvature, by using Microsoft's Kinect™ to obtain 3D reconstructed models of subject's dorsal skin surface in different postures. This method is non-invasive, radiation-free and low-cost. The trial tests here presented intended to evaluate the reliability of this approach, by assessing the tendency of 98 volunteers to present scoliosis. The shoulder height difference was calculated for each subject's scan, by quantifying the angular slope of a line crossing both scapulae. The volunteers' average age was 24.7 years. Results showed that 68.37% of the volunteers revealed differences higher than 1° between the shoulders, having that their record in what concerns to loads and lesions proved to increase the angular slope. This initial approach shall establish the grounds for assessing spinal posture in pre-clinical or industrial ergonomics scans. Further studies shall include comparison versus traditional imaging methods and experienced clinical evaluation.

Trombose da veia central da retina; estudo etiológico e avaliaçäo terapêutica dos casos reunidos nos últimos 2 anos / Central retinal vein occlusion; etiological study and therapeutic evaluation of cases seen in the last two years

A hipertensäo arterial foi a causa mais importante de trombose da veia central da retina nos pacientes acima dos 40 anos de idade. O diabete näo foi täo comum quanto se esperava. Nos poucos casos estudados, a hipertensäo arterial ou a hipercolesterolemia estavam quase sempre presentes. A incidência de trombose da veia central da retina na populaçäo feminina se iguala ao contingente masculino afetado após os 60 anos de idade. Até esta faixa etária as mulheres contam com uma proteçäo hormonal