Feb 10, 2017

Take your next step in MRI – don’t miss the must haves

Estimated reading time: 14-16 minutes

Experts evaluate the recent technological innovations

Recent technological innovations in MRI, such as the next wave in parallel imaging and motion correction techniques, have further reduced scans times and improved imaging quality. There has also been a re-imaging of the ambient environment of the imaging suite. Dr. Jim Pipe of Barrow Neurological Institute (Arizona, USA), and Dr. Chip Truwit of Hennepin County Medical Center (Minnesota, USA) discuss how these changes are transforming clinical practice and the patient experience.

“There have been a host of technological transformations, but the biggest change is that radiology has justly moved forward towards the value proposition of putting the patient at the center of care,” says Dr. Chip Truwit, Chief of Radiology and Chief Innovation Officer at Hennepin County Medical Center. “And that applies to the entire experience that a patient undergoes from the thought of planning an MRI, to the preparation of having MRI, to how they undergo the MRI, to how we deliver the message of the results of the MRI.”

In recent years, changes in healthcare systems and the constantly shifting economic situation have increased the emphasis on healthcare costs and have influenced purchasing and operating models in MRI.

The technological developments have been dramatic"

Turning innovations into clinical benefits

When discussing the expansion of the range of procedures and diagnostic applications of MRI, Dr. Truwit points out, “The technological developments during recent years have been dramatic. For example, we have witnessed the transformation of 3.0T imaging from niche to mainstream. Initially, people weren’t sure if it would be worth the investment. The initial expectation was that 3.0T would be great for neuroimaging, MR angiography, MR spectroscopy, advanced fMRI and DTI applications. However, SENSE matured, 3.0T pulse sequences improved, mDIXON and motion correction were introduced, and the range of applications started to ramp up. We knew neuro would be better, but in addition the strength of 3.0T really resides in musculoskeletal and body applications. What 3.0T has brought to these areas is nothing short of unbelievable. The detail we see now on wrist exams, elbow exams, ankle exams at 3.0T is stunning.”

Sagittal PDw TSE

Voxel size 0.3 x 0.4 x 2.8 mm

Scantime 3:50 min

Ingenia 3.0T

mDIXON XD TSE - PDw (Water Only)

Voxel size 0.4 x 0.6 x 2.5 mm

Scan time 3:05 min

Achieva dStream 3.0T

The power of parallel imaging

A milestone in the advancement of MRI came with parallel imaging. The sensitivity encoding (SENSE) parallel imaging technique enables a reduction in scan times by a factor of two or more. [1] Since its original implementation, continuous improvement of the technique has increased its performance and now dS SENSE* allows greatly increased speed in the routine clinical setting. Faster image acquisition can also help decrease breath-hold times, resulting in reduction of motion artifacts and fewer motion- corrupted images. [2]

“Parallel imaging makes a huge difference in how well we can image the abdomen and parts of the body where there is a lot of motion,” says Dr. Jim Pipe, Director of Neuroimaging Research at Barrow Neurological Institute. “So I think for the clinician it really has helped to extend the scope of MRI. And it makes a difference for the patient experience; in the distant past a lot of abdominal imaging would require a patient to hold breath for a very long period of time. I think just being able to image faster, and maybe image more intelligently over a few respiratory cycles, has made the imaging exam easier on the patient.”

Axial mDIXON

Voxel size 1.6 x 1.6 x 2.5 mm

Scantime 0:11 min

Ingenia 3.0T

Axial mDIXON (Water only, In Phase, Out Phase, Fat only)
Voxel size 1.5 x 1.8 x 4.0 mm
Scantime 0:15 min
Ingenia 3.0T

Overcoming artifacts due to patient motion

Parallel imaging is not the only improvement that has pushed the boundaries, aiming to further shorten scan times without trade-off in terms of image quality. As Dr. Truwit notes, “A second important innovation is Jim Pipe’s development of propeller imaging. Now many vendors have a propeller type of method, such as MultiVane XD** of Philips. The method is based on constructing parts of images at a time, and running the scan so quickly that the second time you run it you acquire another part of the exam, and third time another part of the exam. Then you speed it up like a propeller blade, going so fast you can’t see the cumulative addition of the individual blades or vanes of an exam. So it looks like we are acquiring a single picture – a full picture at one moment in time. And it reduces the amount of time exposure for each part of the image. It almost looks like we are freezing human motion.”

Has the expansion in MRI tools actually had a positive effect in driving improved patient care? “I think that’s an important question,” says Dr. Pipe. “As we advance MRI, do the patients get better? My feeling is that it’s true. But I think our field needs to do a better job of really assessing this. I do think certainly that the volume of information that we can give to a clinician continues to increase based on advancements that have been made in MRI.”

The reality is that we handle a lot more work than we used to"

Axial T2w MultiVane XD

Voxel size 0.6 x 0.6 x 4.0 mm

Scantime 2:00 min

Ingenia 3.0T

Sagittal T2w MultiVane XD

Voxel size 0.7 x 0.7 x 3.0 mm

Scantime 3:37 min

Ingenia 3.0T

Keeping pace with a shifting economic landscape

The volume of MRI scans performed has increased dramatically during the last decade. A study performed within large integrated healthcare systems in the USA revealed a 10% annual increase in the use of MRI during the period 1996–2010. [3]

In addition to increased patient numbers there have also been pressures from the changing patient demographics within society. A recent survey has suggested that the prevalence of obesity in the USA increased by more than two percentage points between 2008 and 2014, to 27.4%. [4] In an already aging population, the greatest obesity rise was seen in people over the age of 65.

“We have the good fortune that although we are being asked to take care of more and more patients, the scanners have made that a realistic possibility,” says Dr. Truwit. “Certainly with the more obese patients, having the wider bore scanners has been important,” says Dr. Pipe. “Just getting a patient in and out of a scanner can be a challenge with certain body types. Having wider bore scanners does facilitate that quite a bit.” “The changes in scanner technology have been significant,” adds Dr. Truwit. “The reality is that we handle a lot more work than we used to and we handle it with much better throughput and less obstacles than we used to. The goal is to be efficient, to be effective, and to do so with the patient’s goals, comfort and safety all foremost in our minds.”

Getting more from your scanner

“Simply increasing efficiency has been one of the major focus areas in the last decade,” Dr. Pipe explains. “A lot of the advances that I see are not just new applications but rather aiming to make applications more robust and collect data more cost-effectively. So, things like faster scanning have in my mind been some of the more substantial advances that we have seen in MRI.”

Are there efficiency gains from getting more information from a single scan? For instance, the mDIXON method that allows to get four contrast types from a single scan? “If you need two to four contrast types, then the ability to collect them all in one scan can lead to huge gains,” says Dr. Pipe. “You can shorten scanning time, and you can have the two pieces of information collected at the exact same time. That allows you to compare images side-by-side and be certain that the different features correspond to each other across the different types of contrast because there can’t be any motion in between. I think that can be very helpful. Also, isotropic scanning is a way that allows to view this information in multiple planes.”

Technological advances in the modern imaging suite have also led to efficiency gains"

“Technological advances in the modern imaging suite have also led to efficiency gains.”

“Technological advances in the modern imaging suite have also led to efficiency gains.”

“Technological advances in the modern imaging suite have also led to efficiency gains.”

Revolutionizing the imaging suite

“Technological advances in the modern imaging suite have also led to efficiency gains,” says Dr. Truwit. “With the conversion to PACS-based Radiology departments, we have seen a dramatic increase in the volume of scans that we can read in a day. Just by not having to physically hang a film but simply clicking on the next one saves time; having the prior studies immediately available saves time and helps to deliver quality in radiology care. Coupling these changes with communication tools to enhance critical results reporting, image sharing for second opinions ‘on the fly’, and regular peer reviews have all raised the bar in radiology.”

“Likewise MRI scanners have allowed for improved throughput. Because of parallel imaging and other changes, such as MultiVane XD** for motion-free imaging, we can perform scans in a shorter period of time. This frees up time to deal with the patient experience. But it also means that we can scan more patients while giving everybody the attention they need.”

I think the total cost of ownership is becoming a much bigger driver these days"

Total cost of ownership can overshadow initial purchase cost

“The fast pace of technological development also has a potential impact on the decision-making process surrounding MRI equipment purchase,” says Dr. Pipe, “Scanners are a bit like computers in the sense that they don’t stay state-of-the-art for very long after buying them. I think the total cost of ownership is becoming a big driver these days. So, having the long-term view is important and upgradability is certainly an important factor."

“The length of time that hospitals keep MRI scanners has stretched a bit,” says Dr. Truwit. “Upgrading a scanner – as opposed to buying a new scanner – is of great appeal to many facilities, especially when one factors in the siting costs related to replacement. Upgrades provide the latest technology without having to buy a whole new scanner. Fewer dollars over a longer period of time, rather than recapitalizing. I think the question of total cost of ownership should be present in everybody’s mind when making these purchases.”

Putting the patient first

“For a patient who is trying to heal, we want to offer a healing environment,” says Dr. Pipe, “I think having an MRI exam is one of the more stressful experiences for a patient while in hospital. Anything we can do to reduce that stress is really good. I see an increasing awareness of the importance of the patient experience. Keeping the stress on them as low as possible is important.”

For patients who experience feelings of helplessness, entering the bore of the scanner can be a quite stressful moment. This led vendors to investigate solutions to make the patient more physically and emotionally comfortable when entering the scanner room and while inside the scanner. These ranged from reducing the distressing level of noise, to providing in-bore entertainment to distract the patient while the scan is proceeding.

There are very few patients that we can’t scan successfully with our very short sequences now"

Enhancing the patient experience with shorter scans

“The increased speed of imaging has also had definite benefits for the overall patient experience, and particularly in scanning difficult patients,” Dr. Truwit says. “There are very few patients that we can’t scan successfully with our very short sequences now. It might not always be a perfect scan in the very difficult patients, but it’s diagnostic.”

“I think for the patient the experience of being in that MR scanner for a much shorter period of time is a big deal,” says Dr. Pipe. “And just anecdotally, I would say that the faster we can get a patient in and out of the scanner, the less chances there are that the patient is going to become agitated or worried and starts moving around and becoming less compliant. We are interested in looking at how we can get the patient in and out of the scanner in a fast enough time so that they will lie still and we can collect high quality data.”

References

[1] Pruessmann KP, Weiger M, Scheidegger MB, Boesiger P. SENSE: sensitivity encoding for fast MRI. Magn Reson Med. 1999;42:952-62.

[2] Deshmane A, Gulani V, Griswold MA, Seiberlich N. Parallel MR imaging. J Magn Reson Imaging. 2012;36:55-72.

[3] Smith-Bindman R, Miglioretti DL, Johnson E, Lee C, Feigelson HS, Flynn M, Greenlee RT, Kruger RL, Hornbrook MC, Roblin D, Solberg LI, Vanneman N, Weinmann S, Williams AE. Use of diagnostic imaging studies and associated radiation exposure for patients enrolled in large integrated health care systems, 1996-2010. JAMA. 2012;307:2400-9.

[4] Levy, J. U.S. obesity rate inches up to 27.7% in 2014. Gallup US Obesity Rate

*dS SENSE provides superior speed performance compared to first generation SENSE (internal bench test comparing dS SENSE to SENSE. Data on file)

**MultiVane XD provides improved motion correction (motion-free) compared to standard TSE and shorter scan times compared to MultiVane thanks to the compatibility with dS SENSE.

About Innovation Matters

Innovation Matters delivers news, opinions and features about healthcare, and is focused on the professionals who work within the industry, as well as Philips as a cutting-edge health technology organization. From interviews with industry giants to how-to guides and features powered by Philips data, our goal is to deliver interesting, educational and entertaining content to empower and inspire all those who work in healthcare or related industries.

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Authors

Chip Truwit, MD, FACR

Chief Medical Officer for Precision Diagnosis at Philips. Previously, Chip was previously Chief of Radiology and Chief Innovation Officer of Upstream Health Innovations at Hennepin County Medical Center, Minnesota, USA, and Professor Emeritus of Radiology at the University of Minnesota

Specialist in neuroradiology with clinical interests in pediatric neuroradiology and intraoperative MR-guided therapy.

Jim Pipe, PhD

Chief of Radiology and Chief Innovation Officer of Upstream Health Innovations at Director of Neuroimaging Research at Barrow Neurological Institute, Saint Joseph's Hospital and Medical Center, Phoenix, Arizona, USA

Wide professional and research interests, including novel acquisition and reconstruction methods, fast scanning, and improving MR value.