It’s not often that a technology drives clinicians to gush, using terms like “phenomenal,” “fantastic” and “exciting.” But 3T MR is doing just that. Greater resolution and faster patient throughput are helping the modality expand its applications and gain even more adoring fans.
Since installing a Signa HDx 3T scanner from GE Healthcare in January 2007, Lloyd Stambaugh, MD, of Evergreen Radia in Kirkland, Wash., can now obtain additional information “that you just can’t get with CT. MR imaging is going to become even more of a routine form of imaging than it is now.”
The practice is positioned in an area of Pugent Sound “where we were really hoping to attract subspecialty MR referrals, particularly for neurology, but also for musculoskeletal applications.” Adding 3T MRI puts the group in a position “to compete for growing subspecialty MRI.”
Stambaugh says the installation went very well and the system was up and running right on schedule. “It took a little time for the radiologists to figure out how to optimize the MR protocols to take the best advantage of what the magnet can do.” But by the end of the summer, neurology, musculoskeletal and body imaging were in line. Two-thirds of the scans are neurology studies, while a third are a combination of body and musculoskeletal imaging.
“To be honest, I wish I could scan all patients on 3T,” Stambaugh says. “The more I use it, the more I like it.” The images look better and he says he feels more confident with his diagnoses, whether he’s finding something abnormal or confirming a normal finding.
The group has seen a 25 percent jump in MR volume over the past year. While some of that growth would have happened regardless of having 3T, “I think 3T has been responsible for a significant chunk of that growth,” he says. “We’ve probably attracted patients who we wouldn’t have attracted [without 3T].” The group has almost tripled its abdominal and pelvic MR scans for a total of 7,200, or almost 15 percent of its business. “That’s a much bigger chunk than a lot of centers. It’s exciting.”
A range of applications
Johns Hopkins Bayview Medical Center in Baltimore, Md., recently installed the Magnetom Verio 3T MR scanner from Siemens Medical Solutions. So far, just body imaging specialist Mark Bohlman, MD, and other volunteers have been imaged. The neurosurgeons were very impressed with the color images of the fiber tracks in Bohlman’s brain. “It’s pretty phenomenal what we’re able to do,” he says.
The facility also imaged its first breast. “I think [breast MRI is] going to be a huge growing area in 3T,” Bohlman says. “It’s better than 1.5 [T] and is very sensitive for detecting early cancers.”
The facility’s cartilage replacement clinic offers another potential use for 3T. Instead of doing knee replacements, patients can have their own cartilage grafted. Bohlman says this is an up-and-coming field in the United States that has been fairly well adopted in Europe. It’s essential to image the cartilage with 3T to ensure that it is viable for implantation.
Johns Hopkins Bayview also plans on using 3T scanner to image overweight patients from the facility’s bariatric center. The Verio has a 70-centimeter bore that can accommodate patients up to 500 pounds. “We’ve never had a way to image these people,” Bohlman says. “Now, we can do state-of-the-art imaging on obese patients.”
3T’s speed also lets Bohlman image bowel loops. “Now we’ve got protocols and sequences that completely get rid of breathing motion. Chest, abdominal and pelvic imaging is going to become commonplace.” Managing patient volume was becoming a problem, he says, so 3T will let the group offer better availability because of faster scans and increased patient throughput.
Chris Goumas, MD, of Palo Alto Medical Foundation in Palo Alto, Calif., started using the Achieva 3T X MR scanner from Philips Healthcare last March for musculoskeletal and neurology imaging. “With musculoskeletal, we’ve seen a 200 to 500 percent increase in resolution relative to 1.5T.”
With an active sports medicine center at Palo Alto, 3T is key for identifying injuries such as small muscular and tendon tears. In neurology, Goumas says they can either get images faster at the same resolution as 1.5T or get increased resolution to see smaller structures. “The MR angiograms of the brain are unbelievably beautiful.”
In most cases, “increased resolution is what we’re after,” he says. In comparing a sagittal knee scan with the same field of view on 1.5T and 3T, he can get 400 to 500 percent smaller voxels. “That’s huge.”
Goumas says physicians are even fighting over the 3T scanner. “One sports medicine orthopedist sees images from all over the country and says the group has the best images in the country right now.”
The practice chose Philips for several features, including parallel imaging, good fat saturation imaging and the ability to decouple the echo spacing on a fast spin echo sequence. “That decreases the blurring on the images,” he says. “We can do extended echo imaging faster.”
In the future
3T’s applications are only going to increase, according to current users. “I think 3T is clearly a mature technology now,” says Stambaugh. “There are going to be continued advances in both sequence design to take advantage of everything you can do with higher magnetic field strength and coils.”
In fact, 1.5T scanners may soon become a thing of the past. “I think that the vast majority of MR purchases going forward are going to be 3T,” he adds. “I can’t imagine people continuing to buy 1.5.”
Goumas thinks 3T is going to supplant the 1.5T market in the next couple of years. Although 3T involves about a one-third price increase over 1.5T, “theoretically, you can do twice as many patients on it. You can actually pay for a 3T scanner faster than a 1.5T scanner if you have the volume.”
He also points out that even facilities that shy away from that price point right now can invest in Philips’ MR series which allows buyers to buy 1.5 now and ramp up to 3T when they’re ready with no forklift upgrade. “That’s awesome,” Goumas says.