Measuring edema
AHFMR Scholar Dr. Richard Thompson can be forgiven for being distracted. While being interviewed for this article in his office at the University of Alberta, he kept one eye on his cell phone—anxiously waiting for news from the University of Alberta Hospital. A new MRI (magnetic resonance imaging) technique developed by his research team was being used for the first time in the clinic. The patient was a premature infant suffering from a serious lung condition called pulmonary hypertension.
"That's the excitement of biomedical engineering—the ability to translate something developed in the lab directly to patients," says Dr. Thompson. "In this case we're using MRI imaging to measure blood flow in the lungs. There are no existing tools to make these measurements in a newborn child. We developed it here and put it to use in the clinic."
For Dr. Thompson, engineering is as much an approach as a discipline. "In my research, I'm not working on a particular disease. Rather, I'm interested in developing new imaging techniques that give physicians and basic scientists the biophysical information that they want but haven't been able to get."
For example, one of his projects is to develop a method to accurately measure edema: the accumulation of fluid in tissues. Edema is an early sign of many diseases including heart disease when the increased pressure in the heart causes fluid to collect in the lungs which appears as cloudiness on lung x-rays. But x-rays don't show the amount of edema, or whether it has changed over time. Measuring edema may be particularly beneficial to patients with heart failure as a non-invasive way to estimate pressure in the heart. Currently, the only way to accurately measure this pressure is to place a catheter in the heart, a procedure that physicians generally try to avoid. In another project, the team is applying the same technique to measure edema within the heart muscle, which can indicate rejection of a transplanted heart. It may be possible to use MRI instead of biopsies heart transplant patients must undergo to check for rejection.
Another interest of Dr. Thompson's is MRI of diastolic heart failure, work that is part of an AHFMR Interdisciplinary Team Grant led by Dr. Jason Dyck at the University of Alberta, and Dr. Todd Anderson at the University of Calgary. In Canada, about 500,000 people are living with heart failure. Nearly half of these patients suffer from diastolic heart failure, which is when the heart muscle doesn't relax properly and allow the heart to fill with blood, and is often caused by a stiff heart muscle. This type of heart failure is very difficult to diagnose, and there are no proven treatments.
"Currently, there's no direct way to measure the mechanisms of this disease, which actually has several distinct forms" says Dr. Thompson. "From my point of view, it's a perfect biomedical engineering problem—we have to develop new ways to measure the mechanisms that give rise to the different manifestations of this disease. It's a massive health problem and scientific challenge, which is why a large team effort is absolutely necessary."