Sending Signals: 3T MRI Implementation is Gaining Strength

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hiit040704While 3T MRI fits the bill as the latest and greatest technology to be introduced to the MR imaging community, not everybody is welcoming the magnet with open arms — cost and complexity remain important factors as to why some physicians and healthcare facilities are on the fence. However, clinical users of 3T are very impressed with the technology’s  imaging capabilities, reporting better imaging of brain, musculoskeletal (MSK) and angiography cases with 3T versus its lower-Tesla cousins. While the decision to install a 3T MRI system is not a straightforward one, users suggest a careful evaluation of one’s imaging services is key. And if the time is right, some advice from the trenches may help ensure a more successful and less painful install.

Sometime in the next two years, Steven Braff, MD, interim radiology chair, department of radiology at Fletcher Allen Healthcare in Burlington, Vt., foresees that 3T will become the new 1.5T standard. “You can’t beat that extra signal,” he says, “signal is the currency of MRI.”

Users gain a lot of extra signal with 3T as compared with lower Tesla magnets, such as 1.5T. Braff says the radiologists at Fletcher Allen, a 500-bed teaching hospital in Burlington that is affiliated with the University of Vermont School of Medicine, are benefiting from the extra signal to noise when reading brain and musculoskeletal images. Neurology applications have proven to be better at 3T and MSK work is rapidly gaining acceptance as a result of the availability of higher channel coils.

One of the primary benefits of imaging with a 3T magnet is that it allows users to either acquire images faster, by using less signal to obtain a diagnostic image, or to go to higher spatial resolution and acquire finer detailed images. But the technology does come at a much higher cost than its lower-Tesla counterparts, and not everybody is convinced the time is right for 3T.

“There is the cost and complexity factors of 3T that are challenges,” says Braff. Coupled with the economics that amount to about $1 million per Tesla, clinical limitations such as increased specific absorption rate (SAR) and prolonged T1 relaxation times, some physicians are still weighing their options — buying a high-end 1.5T system or making the leap to 3T.

“In terms of being able to market it and in terms of getting better images, I think 3T is worth it if you are in a place that is doing enough cases,” says Braff. “If you’re not doing it, your competitor around the block is.”

As hardware and software developments have allowed manufacturers to release a more mature breed of 3T systems, and coil technology continues to improve, 3T is becoming broadly applicable to a large range of clinical applications. It is no longer an experimental modality that serves only niche populations. An increasing number of smaller hospitals and outpatient facilities are adopting 3T today, as opposed to academic hospitals and research facilities — the primary users of 3T just a few years ago.

“If the costs were the same for 1.5T and 3T, then I would say that 3T is the only choice you have to make,” says Larry Tanenbaum, MD, FACR, section chief MRI, CT and neuroradiology at Edison Imaging - NJ Neuroscience Institute, Seton Hall School of Graduate Medical Education in New Jersey. “But they are not the same. What I tell people is that you must consider 3T.”

Just better at 3T

The healthcare facilities that have considered 3T are now using the scanner routinely in clinical practice are impressed with the results, especially in brain and musculoskeletal imaging and MR angiography. Applications clinicians say are improving at 3T but may not be ready for prime time just quite yet include spine, cardiac and breast work.

A 3T magnet fills the role of mainstream MR imaging at Edison. “We have been working with 3T MRI for about six years, and with a short-bore generation system [GE Healthcare’s Signa HDx 3T] for about three years,” says Tanenbaum. “The newer generations of systems are similar to 1.5T in form factor because they have a shorter bore and the same bore circumference [as 1.5T]. They also have high-performance gradients.”

Competitive pressures were important factors as to why Edison started imaging routinely with 3T. “There are a number of orthopedic groups that work with me that insist on 3T, and they refer to me solely because we have this magnet,” says Tanenbaum. “If you have a high-end practice in MSK or neuro, you might be encouraged by your doctors to put