wasn’ t the only advantage.“ When we first developed them, we actually thought that the benefit would mostly reside in the high signalto-noise of these coils,” Rosen said.“ And indeed, the signal-to-noise is unprecedented. More recently, we’ ve come to understand that there is another benefit, which, in the long run, might be even more important. And that’ s that we can use those high-density coils to greatly accelerate the acquisition of the MRI data.”
Such accelerated acquisition, of course, would enable much quicker scan times.
“ GOBrain grew very organically out of this work,” said Larry Wald, Director of the core facility for MRI research in the Center and a Professor of Radiology at Harvard Medical School.“ We’ ve been pushing parallel imaging and improving things by factors of two and three in the clinic. We just came to realize that this could all be put together into a very fast, very efficient brain scan.”
The scanning protocol used with GOBrain incorporates five key pulse sequences employed in the majority of routine brain exams with MRI. Limiting it to these five helped to reduce the scan time to near where the developers wanted it to be. Still, it wasn’ t quite enough to get the total time to within the five minute target.
To address this, they deployed a decidedly low-tech solution: In the typical MRI exam, the technologist will check in with the patient between scans, to see how he or she is doing, explain what is next, etc. But because the brain exam was now so much shorter overall, the technologist no longer needed to talk to the patient between scans. Removing this step of the process helped to shave off the necessary additional time.
Not Just Faster, Better
GOBrain provided the dramatically reduced scan times that the MGH radiologists had asked for, enabling higher throughput and increased efficiency for the hospital and less anxiety and discomfort for the patient. But the developers discovered that it had another, entirely unexpected benefit:“ When we looked at the images, we often found, somewhat to our surprise, that [ they ] were actually significantly better” than those acquired with conventional scanning protocols, Rosen said. This was somewhat counterintuitive;“ you would think if you spend more time acquiring the data it’ s going to take a better picture.” But as it happened, there was a simple explanation.
One of the most common challenges with MR imaging is how to deal with motion artifacts— that is,
The Martinos Center’ s Thomas Witzel
anomalies in the image that result from the subject or patient squirming or otherwise moving around during the scan.
It turns out patients can generally hold still for the five minutes it takes to acquire images with the GOBrain protocol.“ Most patients are not very comfortable with being in a machine for a long time, so they will usually cooperate for the first five to ten minutes and then they will become unruly and start moving more and more,” said Thomas Witzel, the Director of the Human MR Imaging Core at the Martinos Center, and one of the key players in the development of GOBrain.“ So the faster you get all the images the better the quality, because the patient moves a lot less in the beginning of the session.”
The GOBrain application is now in use at Massachusetts General Hospital, where it is living up to its promise of broadly improving MRI brain exams. It is commercially available from Siemens Healthcare.