Standup MRI: A cheap MRI system for visualizing lung function uses parts available at any hardware store. Subjects sitting up and lying down inside the scanner wear an antenna made from a cardboard tube, coils of wire, and a rubber covering. The fence-like arrangement of metal wires directs a weak magnetic field towards the subject. At bottom is Harvard visiting scientist Matthew Rosen, who built the system.
Matthew Rosen/Harvard-Smithsonian Center for Astrophysics
A cheap MRI machine images lung function more realistically.
Magnetic resonance imaging (MRI) can create detailed images of almost all the tissues of the body, allowing doctors to monitor blood flow in the brain, map the borders of tumors, and find slipped spinal discs. But conventional MRI, which images water in the body, produces poor pictures of the lungs, which are full of air, and gives an incomplete picture of lung functions. Now researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, have built a cheap MRI machine that uses a weak magnetic field to image critical aspects of lung physiology that are invisible to conventional imaging techniques.
Led by Matthew Rosen, a visiting scientist at the Harvard-Smithsonian center, and Ronald Walsworth, a senior lecturer in physics at Harvard, the researchers built an MRI scanner that images how gas flows through the lungs and how much oxygen is being absorbed throughout lung tissue. They've used the system to study how lung function differs when lying down and sitting or standing up, and are planning a study of asthma in conjunction with the Martinos Center for Biomedical Imaging in Boston. The system has not yet been used to compare healthy and diseased patients. If it proves its worth in clinical trials, the Harvard researchers believe it would be inexpensive and simple enough to be used in pulmonologists' offices.
Lung function is dependent on the orientation of the body, but it hasn't been possible to study this before because conventional MRI would require patients to lie on their backs. (PET can be used to look at some aspects of the physiology of the lungs but it gives limited information.) Asthma symptoms can be exacerbated when patients lie down, for example. The Harvard system "allows imaging with the patient in any orientation, something no one has ever been able to do," says Bastiaan Driehuys, an assistant professor at the Center for In Vivo Microscopy at Duke University.
The open MRI system may also make it possible to monitor the lung function of newborns in intensive care without taking them out of their incubators. The researchers have filed a provisional patent for this application.
Unlike conventional MRI, which images the protons in water molecules, the Harvard MRI system monitors magnetically polarized helium gas inhaled by subjects. Conventional MRI requires a magnet about 150 times stronger than that in the Harvard system to magnetically align protons inside the body. But the helium used in the Harvard system is magnetically aligned before the patient inhales it, making it possible to use a very weak magnet inside the scanner.
An MRI imager that is 100 million times more powerful could create 3-D images of viruses.
I'd gladly volunteer if it would help figure out why my asthma is worse lying down than anything. Do these people have an email?
Edit: Even though the equipment is rather freaky looking.
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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rdvandell
12 Comments
A Fuller Picture of Your Lungs
Hey, fantastic work!!
Unfortunately, "Radiologists" continue to state they do not understand MRI well enough to support it in favor of X-Rays.
I propose having the "Radiologists" stand outside the shield wall during procedures. Do that and you'll see MRI replace X-Rays in a tick.
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lmwong
1 Comment
Re: A Fuller Picture of Your Lungs
I'm sorry, but that image looks nothing like the MRIs I interpret as a "radiologist". This group is looking at a functional component of the lungs, rather than an anatomical component, much more like a nuclear medicine VQ scan, which gives you very similar nonspecific images to reveal areas of ventilation vs perfusion. An MRI unit is huge and vastly more expensive than an x-ray unit. An x-ray will take a second to do, while an MRI can take minutes to hours. With the number of x-rays done during a day, there's no way an MRI can ever replace x-rays. For bread and butter medicine, an MRI will not give you more information than a simple x-ray will. Some people with metal in their body cannot have MRIs done. The radiation dose of 1 chest x ray equals 10 days of background radiation you get living at sea level. We "radiologists" and radiology technicians stand behind shielded walls because we take hundreds of these x-rays a day, every day of our lives.
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Katherine Bourzac
27 Comments
Re: A Fuller Picture of Your Lungs
lmwong, yes, you're right. They're doing functional, not structural, imaging, so they can't detect, for example, a tumor. Their pictures show not what the lungs look like but how much oxygen they pull in and absorb in different regions. The magnet strength in their machine is only up to about 100 gauss. The idea is not to displace X-rays or conventional MRI, but to build a cheap diagnostic for lung disease that might be simple enough to use in the doctor's office.
The researchers did compare their work to nuclear medicine scans. They say their technique should give the same kind of information without exposing patients to radiation, and should take less time for imaging. However, as they caution, until they build up data from large clinical studies, this is somewhat speculative.
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