New high-field magnets give radiologists the ability to choose between fine, anatomical detail and increased examination speed
A 3T MRI system gives an imaging provider new choices. The full potential of these magnets, commercially available for approximately the past 2 years, is starting to be discovered in richer detail. Linda Moy, MD, assistant professor of radiology at New York University (NYU), says, “With the increased signal-to-noise ratio, you can use it to get really fine anatomical detail, or you can use it to take the images even faster. You also can use it to do a new type of functional imaging, which is much harder to perform at 1.5T; 3T gives radiologists more options. Think of it as extra currency.”
That surplus can be spent in a number of ways, the most prevalent being improved images. In some specialties, the more powerful magnet simply outperforms its 1.5T counterpart. The two main areas in which 3T is significantly superior are musculoskeletal and neurological imaging, according to Steven Mendelsohn, MD, of Zwanger-Pesiri Radiology Group, which operates six imaging centers in New York. “The 3T does a tremendous job with musculoskeletal images, clearly delineating tears in any of the muscle structures that will affect the knee, the shoulder, or smaller joints,” he says. “For orthopedic imaging, 3T is phenomenally better than even the 1.5T system.”
|Robert Day, RT, chief technologist, (left) and Steven Mendelsohn, MD, review plans for a new Zwanger & Pesiri imaging center under construction in East Setauket, on Long Island, NY.|
Scanning at 3T is best for visualizing the smaller bony parts, such as the wrist, fingers, and hands, as well as for obtaining hip arthrograms or unilateral hip MRI. Timothy M. Cotter, MD, director of MRI at 3T Imaging, Morton Grove, Ill, says, “The 3T is also very good at looking for articular-cartilage abnormalities. It increases your confidence because your visualization of the articular-cartilage region is so much greater at 3T.” When it comes to neuroimaging, 3T is significantly better for detection of de-myelinating disease, such as multiple sclerosis, in the spinal cord. Because it shines in specific arenas, the 3T is subject to triage at many centers. “We have both 1.5T and 3T magnets, side by side, in two of our offices right now,” Mendelsohn says. “Our top priority is to put the musculoskeletal cases on the 3T, because the results are dramatically better. Then come the neuro cases, then body imaging, and then fine imaging for back pain, herniated discs, and metastatic disease.”
On their own, finer detail and improved diagnosis might be enough to justify the capital investment needed to acquire a 3T system; however, these scanners not only produce better-quality images, but they also generate the images in considerably less time. In general, this can make a difference in patient throughput at an imaging center. For some examinations, such as breast MRI, it also plays a significant role in improving patient care. “If we know a patient is going to be uncooperative— claustrophobic, for example—telling her that she has to be in the magnet for only 15 minutes, not a half-hour, increases the chance that the patient can complete the study on a 3T scanner that she wouldn’t be able to do on a 1.5T system, because of the shorter scan time.”
Rapid scans also help alleviate concerns about any potential for adverse affects associated with higher specific absorption rates. “For breast MRI, that really has not been an issue, and I think it’s because we have been able to reduce the scan time significantly,” Moy says. More rapid scanning also improves image quality, according to Moy, because a prone patient has difficulty remaining motionless for a half-hour. At NYU, the team has used the 3T system to cut study time almost in half, resulting in reduced motion artifact. A bilateral routine breast examination, for instance, takes 25 minutes on the 1.5T scanner and about 13 minutes on the 3T.
Finding the Best Fit
Although image quality is improved because the patient is able to remain still, Moy reports that the images are comparable to those generated by NYU’s 1.5T magnet. Clinicians must decide for themselves whether to use shorter study times and produce images equal to those from a 1.5T system or invest a bit more time in a slower scan, generating higher-quality images. Exactly how a facility decides to apply these two options varies from one organization to another.
“We have a pretty full day, every day, on the 3T system; until now, we haven’t really used the benefit of the fact that you can go more quickly at 3T,” Cotter says. “Right now, we are doing really high-quality stuff and not really pushing the time, because we don’t need to yet.” Striking the ideal balance between these two capabilities of a 3T system, higher image quality and faster scanning, holds the potential to help facilities remain profitable, even in the face of substantial cuts in reimbursement as a result of the Deficit Reduction Act. (See “The Potential Impact of the DRA” below.)
The increased speed can also be manipulated to make it possible for imaging providers to create extra time slots during the day to work patients into the schedule when necessary. Zwanger-Pesiri Radiology allows for the same amount of scan time whether the procedure is slated for the 1.5T system or the 3T MRI. Brain, spine, and orthopedic cases get 15-minute time slots; breast MRI and cardiac studies will get 30 minutes. “We can get an extra 10 or 15 minutes each hour, so we can have an opening each hour or every 2 hours, which is something we don’t really get on the 1.5T system,” Mendelsohn says. “It really gives us the latitude and the ability to add onto the 3T.” For many referring clinicians, this type of immediate access is very attractive, making it possible for their patients to be scanned on the same day that they determine that imaging is needed.
Reaching Referral Sources
|Lateral breast MR image at 3T exhibits multifocal ductal carcinoma in situ with lymph node involvement, as confirmed with PET.|
Referring physicians will not be able to take advantage of such capabilities, of course, if they are not aware of them. Letting the medical community know about the advantages of a 3T magnet is an important step for imaging providers. When getting the message out about the new technology, Cotter recommends emphasizing the increased image quality available with the 3T. “The easiest thing to market is image quality; that will ring in some doctors’ ears,” he advises. The specialists who most appreciate the improved results are neurologists, orthopedists, and surgeons. “The images are more than just pretty: They help in diagnostic confidence and in arriving at a more definite answer.”
Word of the improved images also is making its way into the patient population, and some imaging centers receive calls asking about the MRI technology being used. Putting out notice that a new 3T system is in place could prove beneficial. “I think that is a very good marketing strategy, because by doing it, you give patients the extra advantage,” Cotter says. “They are going to be their own best advocates, as far as trying to push for the best technical imaging possible.”
Another strategy for keeping a 3T MRI unit busy is to create collaborations with other imaging centers that are unable to afford the new technology. “We are working on creating a relationship with one of the local hospitals. Right now, unless you have an established program, you really can’t do breast MRI because you need to have someplace for the patients to go if they have an abnormality,” Cotter says. The goal is for 3T Imaging to provide access to a state-of-the-art MRI scanner for locations that are unable or unwilling to obtain a system on their own. In return, the imaging centers can add a few studies to the day. “We would be able to offer breast MRI on our 3T scanners,” he says. “It’s just a matter of how to best serve the patient.”
|“In the future, the level of detail 3T provides is going to translate into additional surgeries and newer surgeries to help prevent the long-term progression toward degenerative joint disease and osteoarthritis.”
—Timothy M. Cotter, MD
When 3T scanners were introduced, the biggest complaint associated with them was the additional artifact created by the better signal-to-noise ratio. Such concerns are a thing of the past, according to Mendelsohn. “During the first couple of months of operating the 3T, you have to deal with artifact,” he says. Once you develop your base and your technical skill sets, according to Mendelsohn, artifacts are less of a problem.
The systems themselves can be rather noisy, but this can be avoided. “Although the magnet may inherently be a bit noisier, if people pay attention to the construction of the MRI room and keep the acoustics in mind, they can make the magnet very quiet,” Mendelsohn says. He recommends working with experienced engineers to address any type of vibrational problem. Adjustments can include such features as sound-absorbing walls, along with properly securing the magnet. “Doing it right doesn’t really cost a tremendous amount of money and, in the total scheme of things, is not that much,” Mendelsohn says. “If you are prepared, you do not need to be able to hear it outside the room.”
Molding the Future
By and large, the future looks bright for 3T magnets. As clinical trials continue, and protocols similar to those that exist for 1.5T machines are put in place, the increased visibility of the systems is likely to advance not only diagnosis, but treatments as well. “In the future, the level of detail 3T provides is going to translate into additional surgeries and newer surgeries to help prevent the long-term progression toward degenerative joint disease or osteoarthritis,” Cotter says. “The clinical quality of the 3T is definitely going to shine.”
The Potential Impact of the DRA
Early in 2006, the Deficit Reduction Act (DRA) of 2005 was signed into law. Slated to go into effect in 2007, the regulations limit payments for imaging services performed in nonhospital outpatient settings. Among various other changes, the legislation limits the technical-component reimbursement for outpatient imaging to the Hospital Outpatient Prospective Payment System payment. It also reduces payment for contiguous imaging procedures performed at the same time by 25%. Mammography is not subject to either change.
According to Steven Mendelsohn, MD, of Zwanger-Pesiri Radiology Group (which has six imaging centers throughout New York), “The DRA will radically affect all outpatient practices because it essentially reduces payments on CT scans and MRI by about 25% to 30%.” Mendelsohn adds that the new mandate will force imaging providers to pay closer attention to the bottom line. “Once they analyze the cost of each component, they will be able to improve efficiency. For example, if they can operate safely with only one MRI technologist per machine, then they will do so.”
Two bills concerning access to medical imaging have been introduced: one in the Senate (S 3795) and one in the House of Representatives (HR 5704). If passed, they would require a 2-year moratorium on the cuts in reimbursement for medical imaging. Currently, the proposed legislation is working its way through Congress. If the delay is not enacted, independent centers like 3T Imaging, Morton Grove, Ill—where Timothy M. Cotter, MD, is a partner and director of MRI—will have to arrive at new strategies for maintaining a profitable business.
“Right now, there is a larger margin of profit; therefore, you can go with the 3T system, understanding that you’re going to be able to capture business from the area,” Cotter says. “The fact that you are reimbursed the same amount for 1.5T or 3T means that if the overhead goes up considerably, it’s going to change your perspective.” One solution might be leveraging the faster speed of the 3T system to increase patient throughput at the imaging center. With more studies being done, profit margins would be able to remain intact.
Although one may speculate that concerns about the DRA would dampen sales of 3T, sales of the high-field magnets continued to grow as a percentage of the market in 2006, according to Christopher Boyea, Ultra High Field marketing manager, MRI, Siemens Medical Solutions, Malvern, Penn.
“Obviously, 3T is more expensive, and the DRA may have the unfortunate effect of decreasing the number of 3T magnets that are sold,” Mendelsohn says. “I say ‘unfortunate’ because I think 3T is a significant step in improvement in MRI. The question is whether imaging centers will stop buying them to save money or realize, instead, that buying newer equipment potentially can enable them to scan better and faster. They can make the difference up with an increase in volume and an increase in productivity.”
Dana Hinesly is a contributing writer for Axis Imaging News and Medical Imaging