By Dan Ward

MRs were a game changer in the 1970s when use of the technology to produce three-dimensional anatomical images came to market. It’s an expensive piece of equipment for hospitals and worth every penny for the countless lives it has saved. When I first got into magnetic resonance (MR) imaging as a technologist for a teaching hospital in Chicago, Illinois, a typical brain scan without contrast took an hour or more to complete. Today, those exams last 30 minutes, and they’re producing more data than in the past. Here’s what else has changed in recent years, what you can expect from newer models and what to look for in the future.

Patient comfort
MRs create scans using a strong magnetic field as well as radiofrequency. These scans create detail imaging that may not be seen in other typical imaging modalities.

The coils used to detect and transmit the MR signals have historically been heavy and rigid, generally coming in three sizes, and could only be used one at a time. Recently, new coils have entered the marketplace that are similar to a heating pad or small blanket to transmit the signal This offers greater flexibility and allows better positioning and handling for the technologist. Additionally, multiple coils can be used at once for improved coverage of the anatomy.

Researchers at the National Institute of Biomedical Imaging and Bioengineering, part of the National Institutes of Health, say flexible MRI coils may reduce the amount of time it takes to perform a scan, which, depending on the patient and the issue, can still take up to an hour. Because the patient must lie perfectly still during this time, any reduction in length of scan is an improvement.

A reduced scan time increases comfort for the patients who, on older models, must also endure loud noises and bright lights. During a typical MR, a patient would have to wear headphones or plugs in their ears to withstand the noise. The sound intensity can get up to 120 decibels in certain MR scanners. Compare this to a motorcycle or dirt bike, whose average noise levels range from 80 to 110 decibels. Now think of it next to your head. Not very appealing, is it? The newer magnets are much quieter. You can actually have a conversation during a majority of the sequences, which would be impossible with the older models.

In addition, new MR scanners are equipped with lighting inside the core of the magnet as well as ambient lighting that some facilities implement, which makes the system look less intimidating and sterile-looking, as well as less frightening, especially to children. Some even have an entertainment system, including video and music.

Remember the news stories about claustrophobic patients panicking during MRs? Newer models have larger tunnels and more air circulating through them to create, if not a more pleasant experience, then certainly one that is less unpleasant.

Patient care
In addition to patient comfort, improvements to patient care encompass efficiency, technology and overall patient well-being. MR scanners are being used in radiation therapy to plan treatment. The MR uses the same type of table used in CT (computed tomography). MR scans have improved resolution as compared to CT scanners.

The new MR electronically sends its data, including patient positioning, to the linear accelerator. Using this data, the oncology system’s radiation beams have a more precise target, and thereby reduce the amount of collateral damage during the treatment of the patient. By bringing together MR technologists and radiation therapists with this new technology through cross-training, hospitals can achieve better clinical outcomes.

Newer MR systems are built with a larger bore, or the bore is oval in shape. The oval shape MR system accommodates the natural shape of the body at rest.

In more good news, MRs on the market today are engineered for helium reduction. MRs work by using electronic magnets, which must be kept at approximately 0 degrees Kelvin, and helium provides that cooling power. The problem is that helium is a finite source, and because it cannot be manufactured, once it’s used, it’s gone.

Nearly all the manufacturers on the market today have gone to zero boil-off, or close to it, and it can be two to three years before a system has to be refilled. Newer models are much more efficient in recapturing the helium than they were in the past.

Recently, one manufacturer developed a sealed system, which uses much less helium and doesn’t require any boil-off. When it needs to be quenched, i.e., refilled, it requires only seven liters of liquid helium and it is totally sealed. This new technology further reduces the amount of helium being used in the world, which then extends the length of supply availability.

For the future, look for coil technology to improve. Coils will continue to get smaller, and vendors will continue to improve resolution that will improve patient care and increase patient comfort.

About the author: Dan Ward is a senior portfolio executive for Vizient in the diagnostic imaging team under capital, imaging and facilities. He works closely with industry and hospital members in the diagnostic imaging, informatics and oncology space.