The heart is a dynamic, beating organ, and until now it has been challenging to fully capture its complexity by magnetic resonance imaging (MRI). In an ideal world, doctors could create a 3-D visual representation of each patient’s unique heart and watch as it pumps, moving through each phase of the cardiac cycle. Andrew Powell, MD, Chief of the Division of Cardiac Imaging at Boston Children’s Hospital, and his physicist colleague Mehdi Hedjazi Moghari, PhD, have taken steps toward realizing this vision.
The standard cardiac MRI includes multiple 2-D image slices stacked next to each other that must be carefully positioned by the MRI technologist based on a patient’s anatomy. Planning the location and angle for the slices requires a highly-knowledgeable operator and takes time.
Powell and Moghari are working on a new MRI-based technology that can produce moving 3-D images of the heart. It allows cardiologists and cardiac surgeons to see a patient’s heart from any angle and observe its movement throughout the entire cardiac cycle. …
Some 5 to 17 percent of all children have developmental dyslexia, or unexplained reading difficulty. When a parent has dyslexia, the odds jump to 50 percent. Typically, though, dyslexia isn’t diagnosed until the end of second grade or as late as third grade — when interventions are less effective and self-esteem has already suffered.
“It’s a diagnosis that requires failure,” says Nadine Gaab, PhD, an investigator in Boston Children’s Hospital’s Laboratories of Cognitive Neuroscience.
But a new study led by Gaab and lab members Nicolas Langer, PhD, and Barbara Peysakhovich finds that the writing is on the wall as early as infancy — if only there were a way to read it and intervene before the academic, social and emotional damage is done. …
MRI is a staple of surgical imaging, but it has the potential to do much more than take pictures. In 2011, bioengineer Pierre Dupont, PhD, and colleagues demonstrated that an MRI machine’s magnetic field could power a motor strong enough to control a robotic instrument, in this case driving a needle into an organ to do a biopsy.
But Dupont, head of the Pediatric Cardiac Bioengineering Lab at Boston Children’s Hospital, wants to go further. “We had this idea, admittedly fanciful: What if you could swim robots through the body?” he says. “If you could inject something systemically and steer it to just hit your target, that would be a cool application.” …
Diffusion tensor imaging (DTI), a form of magnetic resonance imaging, has become popular in neuroscience. By analyzing the direction of water diffusion in the brain, it can reveal the organization of bundles of nerve fibers, or axons, and how they connect—providing insight on conditions such as autism.
But conventional DTI has its limits. For example, when fibers cross, DTI can’t accurately analyze the signal: the different directions of water flow effectively cancel each other out. Given that an estimated 60 to 90 percent of voxels (cubic-millimeter sections of brain tissue) contain more than one fiber bundle, this isn’t a minor problem. In addition, conventional DTI can’t interpret water flow that lacks directionality, such as that within the brain’s abundant glial cells or the freely diffusing water that results from inflammation—so misses part of the story. …
Experience suggests that magnetic resonance imaging (MRI) and advanced MR techniques such as spectroscopy and diffusion imaging offer substantial benefits when diagnosing problems in premature babies. However, today’s MR systems poses significant logistical barriers to imaging these infants. We have been working to change that.
MRI provides an unparalleled ability to visualize anatomy without the hazards of ionizing radiation. Yet premature and sick babies in neonatal intensive care units (NICUs) are usually too delicate to leave the unit. The few babies who receive MRI today must be accompanied by NICU staff during transport to and from the Radiology Department. This process is often a multi-hour ordeal and reduces the staff available to care for other babies in the NICU. Moreover, infants must be imaged in an adult-sized MRI scanner …
Magnetic resonance imaging, or MRI, can produce stunningly detailed images of the body’s tissues and structures. Historically, however, the chest—and in particular, the lungs and airway—has proven challenging for radiologists to clearly visualize through MR images.
Why is that? Unlike most other solid organs, the lung and trachea aren’t really solid. The air spaces within them do not absorb the magnetic fields or produce the radio signals needed to generate high-quality diagnostic images. Also, they are in constant motion—we have to breathe, after all.
“We know very little about what’s happening in the developing brain in three dimensions,” says Emi Takahashi, PhD, a researcher in the Fetal-Neonatal Neuroimaging & Developmental Science Center (FNNDSC) at Boston Children’s Hospital. “With histology techniques, we can achieve a two-dimensional view over small areas, but it’s hard to know which fiber bundles are growing in which ways during different stages of development in the whole brain.”
But new MRI-based technologies are quickly closing that knowledge gap, giving us our first high-resolution peek into how the developing brain wires itself up.
Using something called high angular resolution diffusion imaging (HARDI) MRI, Takahashi and her colleagues (including neuroradiologist and FNNDSC director P. Ellen Grant, MD) can trace the three-dimensional pathways within the growing brain via stunning images like these:
It began as a proof-of-principle demonstrated with LEGOs – a surgical biopsy needle whose motor is driven solely by a clinical MRI scanner:
The above demo shows that an MRI machine’s magnetic field can be programmed to produce enough force to control a robotic instrument — an accomplishment with broad potential in medicine. In the demo, the scanner’s magnetic field swings a rotating arm, and a set of gears convert that motion into the motion of a biopsy needle, strong enough to puncture the tough outer tissue of an animal heart and then withdraw. All parts exposed to the magnetic field are metal-free and MRI-compatible.
While MRI-compatible robots have been built before, this was the first demo of a motor powered by MRI, says Pierre Dupont, chief of Pediatric Cardiac Bioengineering at Children’s Hospital Boston. His engineering team was one of five finalists for Best Paper Award — out of 790 papers presented — at last week’s International Conference on Intelligent Robots and Systems (IROS 2011). …