Characterization of the dynamic mechanical behavior of brain tissue is essential for understanding and simulating the mechanisms of traumatic brain injury (TBI). Changes in mechanical properties may also reflect changes in the brain due to aging or disease. In this study, we used magnetic resonance elastography (MRE) to measure the viscoelastic properties of ferret brain tissue in vivo.
In the context of motion tracking and virtual reality, there is a strong need for sensors to monitor the motion of a moving object. These sensors are characterised by their performances (ranges, accuracy, drifts, and susceptibility to the ambient environment) and embedded (small size, light weight). The magnetic technology compared to the mechanical or optical solution allows the working without structural skeleton composed of links interconnected by monitored joints and with possible optical shadows.
The performances offered by Magnetics Resonance Imaging (MRI) are widely recognized and used by practitioners. Mainly used for diagnostic issues, MRI becomes more and more an interventional tool in image-assisted classic or robotic surgery. However, constraints imposed by the MRI strong magnetic field and strong magnetic gradients in terms of material and architecture are often obstacles to MRI guided robotics. Designers have to deal with the few choices offered to them to build a robot which will be able to respond to severe specifications, in terms of space limitations, magnetic field sensitivity and image impact. Piezoelectric micro-motors are good candidates to fulfil these requirements in several fields of applications.
Off-pump Coronary Artery Bypass Grafting (CABG) is still today a technically difficult procedure. In fact, the mechanical stabilizers used to locally suppress the heart excursion have been demonstrated to exhibit significant residual motion. We therefore propose a novel active stabilizer which is able to compensate for this residual motion. The interaction between the heart and a mechanical stabilizer is first assessed in vivo on an animal model. Then, the principle of active stabilization, based on the high speed vision-based control of a compliant mechanism, is presented. In vivo experimental results are given using a prototype which structure is compatible with a minimally invasive approach.
Implementation of 3D capabilities on ultrasonic imaging systems tantalizingly proves the high interest for this diagnosing modality. However, to become a clinical tool, 3D ultrasound has to spend further technological efforts in acquisition performance and probe size to deliver on the fly, quality volumetric images as well as current functionalities.