Archive for month: August, 2020

A Yale-led team of researchers developed a new approach to scanning the brain for changes in synapses that are associated with common brain disorders. The technique may provide insights into the diagnosis and treatment of a broad range of disorders, including epilepsy, Alzheimer’s disease, schizophrenia, depression and Parkinson’s disease.
Certain changes in synapses – the junctions between nerve cells in the brain – have been linked with brain disorders. But researchers have only been able to evaluate synaptic changes during autopsies. For their study, the research team set out to develop a method for measuring the number of synapses, or synaptic density, in the living brain.
To quantify synapses throughout the brain, professor of radiology and biomedical imaging Richard Carson and his co-authors combined PET scanning technology with biochemistry. They developed a radioactive tracer that, when injected into the body, binds with a key protein that is present in all synapses across the brain. They observed the tracer through PET imaging and then applied mathematical tools to quantify synaptic density. The researchers used the imaging technique in both baboons and humans. They confirmed that the new method did serve as a marker for synaptic density. It also revealed synaptic loss in three patients with epilepsy compared to healthy individuals.
‘This is the first time we have synaptic density measurement in live human beings,’ said Carson, who is senior author on the study. ‘Up to now any measurement of synaptic density was post-mortem.’
The finding has several potential applications. With this non-invasive method, researchers may be able to follow the progression of many brain disorders, including epilepsy and Alzheimer’s disease, by measuring changes in synaptic density over time. Another application may be in assessing how pharmaceuticals slow the loss of neurons. ‘This opens the door to follow the natural evolution of synaptic density with normal aging and follow how drugs can alter synapses or synapse formation.’

Yale University http://tinyurl.com/hnrz9y8

In the operating room of the future, robots will be an integral part of the surgical team, working alongside human surgeons to make surgeries safer, faster and more precise. Engineers in Michael Yip’s lab at UC San Diego are developing advanced robotic systems to help make that vision a reality.

From intelligent algorithms that can enable robots to lend a helping hand during surgery, to ‘smart’ endoscopes that can autonomously maneuver through sensitive nooks and crannies inside the body, the robotics technologies in Yip’s lab are all inspired by a common goal: to augment the capabilities of surgeons.

The goal is not to replace human surgeons, but to better assist and enable them to do much more, said Yip, a professor of electrical engineering. Human surgeons, he explained, are still needed to make decisions that can’t be left to a robot, such as what treatment is best for the patient, or how a surgical procedure should be performed.

Meanwhile, robots will be used to perform tasks that humans cannot. For example, flexible and dexterous robots armed with high-power computing and sub-millimeter precision will be able to perform minimally invasive surgery, control complex instruments and navigate through spaces in the body that a human surgeon can’t access. These robots could perform other advanced tasks, such as creating real-time 3D maps inside the body as they self-navigate, relying on a patient’s medical data and imaging information.

This vision illustrates the idea of ‘Shared Autonomy,’ the theme of the most recent UC San Diego Contextual Robotics Institute Forum held on campus during October. In an age of increasing automation, researchers in the institute, such as Yip, are focused on developing robotic systems that can interact well in a human world and benefit society.

The da Vinci Surgical System is a robotic surgical system designed to perform minimally invasive surgery. The system, developed by the company Intuitive Surgical, is remotely controlled by a surgeon from a console. The system is equipped with four robotic arms, but a surgeon is able to control only two of them at a time. Yip’s ARCLab currently has a full da Vinci Surgical System dedicated for research in shared autonomy.

Yip’s team aims to put the other two arms to work. To do this, they are creating software and hardware that will enable these arms to function autonomously. A goal is to have these robotic arms assist the primary surgeon with routine surgical tasks (suction, irrigation or pulling tissue back) that are tedious and are currently performed by additional human surgeons.

‘This would reduce the number of surgeons in the operating room, which would reduce the overall cost of the surgery,’ said Nikhil Das, an electrical engineering Ph.D. student in Yip’s lab. It would also free up surgeons who normally do these tasks to see other patients, he added.

Das develops motion planning algorithms that will enable the auxiliary arms to move without hitting obstacles, such as the surgeon-controlled manipulator arms. He is working on this project with undergraduate student Naman Gupta, who is visiting from Birla Institute of Technology and Science in Pilani, India. Gupta implements these algorithms in a simulated da Vinci system’s robotic arm and is in the process of validating his approach before moving it onto the ARCLab’s da Vinci system.

Other students in the ARCLab are incorporating haptics into the system so that surgeons operating the robotic arms can recover the textures and sensations of feeling the tissues, a critical sensation missing in current systems.

‘We’re trying to close the gap between the surgeon and the robot,’ Das said.

To reach truly small scales, the ARCLab is developing its own robotic catheters. These catheters are meter-long, millimeter-diameter flexible robots that can access the deepest parts of the body from atraumatic locations such as the leg. With 8 wires that are individually controlled by 8 different motors, Yip’s lab can shape and steer the robot catheters in more complex configurations and navigate far more effectively than surgeons could do manually.

One goal is to automate the catheter and incorporate haptic controls so that the operator can receive feedback from the motors. ‘That’s what makes our catheter different from the steerable catheters in industry,’ said Aaron Gunn, a mechanical engineering undergraduate working on this project.

University of California San Diego ucsdnews.ucsd.edu/feature/engineers_developing_advanced_robotic_systems_that_will_become_surgeons

Michigan Medicine researchers employ novel technology to monitor vulnerabilities for cardiovascular events, aid in diagnosis and treatment
Strokes and heart attacks often strike without warning. But, a unique application of a medical camera could one day help physicians know who is at risk for a cardiovascular event by providing a better view of potential problem areas.

‘The camera actually goes inside the vessels,’ says first author Luis Savastano, M.D., a Michigan Medicine resident neurosurgeon. ‘We can see with very high resolution the surface of the vessels and any lesions, such as a ruptured plaque, that could cause a stroke. This technology could possibly find the smoking gun’ lesion in patients with strokes of unknown cause, and may even be able to show which silent, but at-risk, plaques may cause a cardiovascular event in the future.’

The scanning fibre endoscope, or SFE, used in the study was invented and developed by co-author and University of Washington mechanical engineering research professor Eric Seibel, Ph.D.. He originally designed it for early cancer detection by clearly imaging cancer cells that are currently invisible with clinical endoscopes.

The Michigan Medicine team used the instrument for a new application: acquiring high-quality images of possible stroke-causing regions of the carotid artery that may not be detected with conventional radiological techniques.

Researchers generated images of human arteries using the SFE, which illuminates tissues with multiple laser beams, and digitally reconstructs high-definition images to determine the severity of atherosclerosis and other qualities of the vessel wall.

A unique application of a medical camera could one day help physicians know who is at risk for a cardiovascular event by providing a better view of potential problem areas.

‘In addition to discovering the cause of the stroke, the endoscope can also assist neurosurgeons with therapeutic interventions by guiding stent placement, releasing drugs and biomaterials and helping with surgeries,’ Seibel says.

In addition, the SFE uses fluorescence indicators to show key biological features associated with increased risk of stroke and heart attacks in the future.

‘The ability to identify and monitor the biological markers that render a plaque unstable and at risk for rupture could enable the detection of individuals within high-risk populations who are most likely to suffer from cardiovascular events, and therefore benefit the most from preventive treatment during the asymptomatic stage,’ says B. Gregory Thompson, M.D., professor of neurosurgery at the University of Michigan Medical School and a senior author on the new paper.

University of Michigan www.uofmhealth.org/news/archive/201702/laser-based-camera-improves-view-carotid-artery

Important steps in planning tumour surgery include identifying borders between tumour and healthy tissue and assessing the tumour stiffness, e.g. hard and calcified or soft and pliant. For decades, tumours near the surface of the body have been evaluated for stiffness by simple palpation-the physician pressing on the tissue. Because tumours within the skull cannot be palpated, researchers used Magnetic Resonance Elastography (MRE) to assess pituitary tumour stiffness by measuring waves transmitted through the skull into pituitary macroadenomas (PMAs). MRE reliably identified tumours that were soft enough for removal with a minimally-invasive suction technique versus harder tumours requiring more invasive surgery.
‘The group developed brain MRE several years ago and is now successfully applying it to clinical diagnosis and treatment,’ explained Guoying Liu, Ph.D., Director of the NIBIB Program in Magnetic Resonance Imaging. ‘This development of a new imaging technique followed by its practical application in surgical planning for better patient outcomes is an outstanding example of one of the main objectives of NIBIB-funded research.’
MRE is a special magnetic resonance imaging technique that captures snapshots of shear waves that move through the tissue and create elastograms-images that show tissue stiffness. John Huston III, M.D., Professor of Radiology at the Mayo Clinic in Rochester, MN, and senior author of the study, explains how MRE works. ‘MRE is similar to a drop of water hitting a still pond to create the ripples that move out in all directions. We generate tiny, harmless ripples, or shear waves, that travel through the brain of the patient. Our instruments measure how the ripples change as they move through the brain and those changes give us an extremely accurate measure–and a coloUr-coded picture–of the stiffness of the tissue.’
Ninety percent of PMAs are soft-nearly the consistency of toothpaste. Therefore, without MRE, surgeons would routinely plan for a procedure called transphenoidal resection that employs very thin instruments that are threaded through the nasal cavity to the pituitary gland at the base of the skull, where suction is used to remove the tumour. However, in about 10percent of the cases, the surgeon will encounter a hard tumour. At that point an attempt is made to break-up the tumour-essentially chipping away at it with sharp instruments. If that is not successful, the surgeon must perform a fully-invasive craniotomy that involves removing a piece of the skull bone in order to fully expose the tumour.
The more extensive procedure means added risk and discomfort for patients, and up to a week-long recovery in the hospital compared to the transphenoidal approach that allows patients to leave the hospital in a day or two. Using MRE, hard PMAs can be identified and the more extensive craniotomy can be planned before starting the surgery, which makes the more invasive procedure less taxing for both the surgeon and patient. Similarly, MRE showing a soft PMA gives surgeons confidence that the nasal entry and removal by suction will be successful-eliminating the likelihood that the surgeon may need to perform a second fully-invasive craniotomy.

NIBIB http://tinyurl.com/gu285fb

A multidisciplinary research team led by University of Houston scientist Jarek Wosik has developed a high-temperature superconducting coil that allows magnetic resonance imaging (MRI) scanners to produce higher resolution images or acquire images in a shorter time than when using conventional coils.
Wosik, a principal investigator at the Texas Center for Superconductivity at UH, said test results show the new technology can reveal brain structures that aren’t easily visualized with conventional MRI coils. He also is a research professor in the UH Department of Electrical and Computer Engineering.
The cryo-coil works by boosting the signal-to-noise ratio (SNR) – a measure of the strength of signals carrying useful information – by a factor of two to three, compared with conventional coils. SNR is critical to the successful implementation of high resolution and fast imaging.
Wosik said the cryo-coil reveals more details than a conventional coil because of its enhanced SNR profile. Where a conventional coil does not have enough sensitivity to ‘see,’ a superconducting coil can still reveal details. These details will remain hidden to conventional coils even when image acquisition is repeated endlessly.
For the initial tests, the probe was optimized for rat brain imaging, useful for biomedical research involving neurological disorders. But it also has direct implications for human healthcare, Wosik said.
‘Research in animal models yields critical information to improve diagnosis and treatment of human diseases and disorders,’ he said. ‘This work also has the potential to clearly benefit clinical MRI, both through high quality imaging and through shortening the time patients are in the scanner.’
Results from preliminary testing of the 7 Tesla MRI Cryo-probe were presented at the 2016 International Symposium of Magnetic Resonance in Medicine annual meeting last May. The coil can be optimized for experiments on living animals or brain tissue samples, and researchers said they demonstrated an isotropic resolution of 34 micron in rat brain imaging. In addition to its use in MRI coils, superconductivity lies at the heart of MRI scanning systems, as most high-field magnets are based on superconducting wire.
Compared to corresponding standard room temperature MRI coils, the performance of the cooled normal metal and/or the high-temperature superconducting receiver coils lead either to an increase in imaging resolution and its quality, or to a very significant reduction in total scan time,’ Wosik said.

University of Houston http://tinyurl.com/jzrln92