1.5 + 1.5 = 3, right? So a 3T MRI is twice as good as a 1.5T MRI, right? As far as the field strength is concerned, sure. In the world of sales and marketing, absolutely. But from an imaging standpoint, a throughput standpoint, and a cashflow standpoint, maybe not.
Before you spend up to twice the money for a 3T, we suggest you take a look at what it can do for you, and what it can’t. Read more below, or watch the video version of this blog at the foot of the page.
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1.5T MRI Machines Are Still Standard
Even with the emergence of 3T technology, a 1.5T MRI is completely adequate for most MRI scans that are done in the U.S.A. today. The 1.5T short-bore MRI remains the standard and accounts for the vast majority of scanners currently in use.
It’s not that 3Ts haven’t “caught on", but considering the climate of consolidation, reimbursement changes, patient needs, and competition there’s a real need to be deliberate about equipment choices, especially when weighed against facility improvements, staffing, and needs coming from other modalities. After all, though the price tag to acquire a 3T is substantially higher than a 1.5T, the federal reimbursement is the same for both.
Drown out the Noise or Turn Down the Volume?
One of the biggest selling points for 3T is its ability to reduce image noise. Image noise is always present in an MRI scan – almost like static in a television image. Most noise actually comes from the patient’s body and the electronics inherent to the MRI system. The goal is to have more signal creating image than noise that can affect quality. This can be done by both 3T and 1.5T MRI scanners, but in different ways.
All of you parents out there may find it helpful to consider this analogy:
10 year-old girls can be very loud- especially if they congregate at a birthday party- so parents plan games to keep them busy until the party can, mercifully, end. If you wish to have a proper game of musical chairs, you have two choices if you want everyone to hear the music:
- Turn up the volume
- Quiet the children
A 3T system is like your stereo, playing kiddie music at top volume. It gives you more signal (more molecules resonating in the magnetic field) to drown out the noise. A 1.5T system using multi-channel phased array coils works from the other end. With more coil elements closer to the anatomy being studied, you're able to "quiet the children" and reduce the amount of noise being produced in the first place.
MRI Machine Speed and your Imaging Needs
MRI studies are a compromise between scan time and image quality. Faster scans aren't as clear as longer ones, but longer ones can make your MRI suite a bottleneck for your facility. Many MRI buyers seek a 3T scanner as a balanced remedy for this dilemma: better image clarity at comparable scan times to a 1.5T, or a slight sacrifice in clarity for significant time savings.
You can still get beautiful images with a 1.5T system using multi-channel phased array coils, but scan times are longer than a 3T. Conversely, you can shorten scan times with a 1.5T system too, but the image quality sacrifice will be more than on a 3T. It all depends upon the type of study that’s needed. Like choosing between a Chevrolet and a Formula One racecar- both will get you where you need to go, but before you buy one or the other, it’s important to assess how quickly you actually need to get there.
Supply and Demand
If you’re doing studies that involve very minute detail, (sophisticated brain work is a categories in which 3T really shines) or if your market area, volume, or referring doctors are leaning you toward 3T, then be sure to plan ahead. 3T is costly. Even on the secondary market the pricetag could easily be double what you’d pay for a 1.5T.
Give yourself time to locate a 3T. Availability has increased, but they're still not as common as their 1.5T counterparts.
Make sure your room can accommodate a 3T. Typically, the active shielding on these magnets is good enough to contain the five-gauss line in a moderately sized room, but some testing is in order to make sure. Keep in mind: the strength of magnets used to pick up cars in junkyards is about the same as a 1.5T MRI. 3Ts have twice as much magnetic field. Be sure your safety measures are sufficient!
If your studies will be less detailed or your pace will be less hectic, you’ll be able to get everything you need from a 1.5T system equipped with multi-channel coils. These systems are more readily available, as are replacement parts and service engineers to keep them running.
If your work will be of the most delicate nature, or if your patient volume is particularly high, the crisper image clarity and potential time savings of a 3T system could be worth investing in.
3T MRI vs. 1.5T MRI [VIDEO]
Written by Steve Rentz
Steve Rentz is the Product Manager for MRI Scanners at Block Imaging. He is also a husband, father of 3, triathlete, woodworker, and barbecue master. Steve’s goal is to earn each customer’s trust and business by specifically addressing the needs of their unique project.