Some believe that magnetic resonance imaging (MRI) has reached its limits and there is nowhere else for it to go. Then there are those like Texas A&M University assistant professor of biomedical engineering Mary McDougall, who is working to push MRI beyond its current state.
"Because MRI is already used by doctors, it is a common misconception that it is a 'fully cooked' diagnostic tool," McDougall says. "In fact, research in MRI is incredibly active and dynamic, and much of that has to do with innovations in hardware and methodology that will ultimately help us diagnose and treat disease differently."
McDougall, who earned her bachelor's degree from Texas A&M in electrical engineering and her master's from Johns Hopkins, returned to Texas A&M and focused her doctoral research on biomedical imaging and MRI, earning her Ph.D. in electrical engineering. McDougall, along with her colleagues, is in the midst of two research projects, in collaboration with clinical sites, aimed at taking MRI to the next level.
One study involves using a 3-Tesla (3T) magnet, whereas the other uses an even more powerful 7T magnet. These are large superconducting magnets that produce these field strengths. To grasp just how massive the superconducting magnets are, compare them to Earth's magnetic field, which at 0.00005T seems minuscule.
"Research in MRI is incredibly active and dynamic, and much of that has to do with innovations in hardware and methodology that will ultimately help us diagnose and treat disease differently."
"We have largely focused the work in our lab on highly accelerated imaging, giving us the ability to see dynamics with MRI that were not previously possible," McDougall says. "Our clinical collaborations have the same goal: taking MRI beyond what is conventional."
Scanning at 7T
One project McDougall is working on, with researchers at UT Southwestern Medical Center in Dallas, involves using a 7T magnet, the highest field strength available for clinical research. Most MRI units in hospitals are 1.5T, but manufacturers are making whole-body scanners at 7T strength and providing support, and UT Southwestern is currently home to the only 7T clinical MRI scanner in Texas.
"It is such a new 'toy' that it is really interesting to us," McDougall says of the 7T magnet.
Sponsored by the Cancer Prevention Research Institute of Texas, the project focuses on multinuclear spectroscopy and imaging and is being conducted primarily on breast cancer patients. The project's goal is to reduce the time to determine whether a patient is responding to cancer treatment.
"It is a very exciting project," McDougall says. "Currently using MRI, you take an image, the woman goes off and gets her treatment for a period of time and then she comes back. Then you take another image to see if the tumor has shrunk. That is the modus operandi right now, to judge response to treatment, and it is really slow.
"We have largely focused the work in our lab on highly accelerated imaging, giving us the ability to see dynamics with MRI that were not previously possible. Our clinical collaborations have the same goal: taking MRI beyond what is conventional."
"The ideal scenario that you would envision instead would be that she gets treatment, and within hours you would know whether or not she is responding positively by receiving spectroscopic information from that tumor. From that spectroscopic signature, you can gain knowledge about the sensitive chemical content of the tumor, which will change in response to treatment long before you could see a change in the size of the tumor.
"The real feasibility of this is just now being made possible with the signal provided by the higher-field-strength magnet."
Though now focused on breast cancer patients, this work, if successful, could be used with other forms of cancer as well.
"100 percent, yes, it can be applied to other areas if it were to work," McDougall says.
Benefits and challenges
Higher field strength yields greater signal, in turn offering a host of advantages to the field of MRI. Among them is the possibility of increasing a scan's spatial or temporal resolution, or giving medical researchers and professionals better chemical information.
Despite these enormous advantages, higher field strength — particularly 7T — also has some challenges. Although these drawbacks are limiting the potential of what appears to be a powerful new tool in the realm of MRI, researchers are working to overcome these obstacles.
"It is becoming apparent that addressing these challenges is going to require research and development on the hardware and methodology side in large part," McDougall says. "We are developing specialized RF [radiofrequency] technology to help mitigate the challenges of working at 7T in order to get better images and spectroscopic information."