Researchers develop MRI with lower magnetic field for cardiac and lung imaging

Redesigned
MRI holds promise for the diagnosis and treatment of diseases.

National
Institutes of Health researchers, along with researchers at Siemens, have
developed a high-performance, low magnetic-field MRI system that vastly
improves image quality of the lungs and other internal structures of the human
body. The new system is more compatible with interventional devices that could
greatly enhance image-guided procedures that diagnose and treat disease, and
the system makes medical imaging more affordable and accessible for patients.

The low-field MRI system may also be safer for patients with pacemakers or defibrillators, quieter, and easier to maintain and install. The study, “Opportunities in Interventional and Diagnostic Imaging by Using High-performance Low-Field-Strength MRI” was funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health of U.S. Government, appears in the journal Radiology.

Metal
devices now safe for real-time, image-guided procedures ?

The trend in
recent years has been to develop MRI systems with higher magnetic field
strengths to produce clearer images of the brain. But, researchers calculated
that using those same state-of-the-art systems — at a modified strength — might
offer high quality imaging of the heart and lungs. They found that metal
devices such as interventional cardiology tools that were once at risk of
heating with the high-field system were now safe for real-time, image-guided
procedures such as heart catherization.

“We continue
to explore how MRI can be optimized for diagnostic and therapeutic
applications,” said Robert Balaban, Ph.D., scientific director of the Division
of Intramural Research and chief of the Laboratory of Cardiac Energetics at
NHLBI. “The system reduces the risk of heating — a major barrier to the use of
MRI-guided therapeutic approaches that have hampered the imaging field for
decades.”

MRI of
the lung : A notoriously difficult task

The
researchers also found that lung imaging improved and that oxygen itself can be
observed in tissue and blood much better at a lower magnetic field, providing a
unique view of the distribution of this vital molecule in the body.

“MRI of the
lung is notoriously difficult and has been off-limits for years because air
causes distortion in MRI images,” said Adrienne Campbell-Washburn, Ph.D., a
staff scientist in the Cardiovascular Branch at NHLBI and the study’s author.
“A low-field MRI system equipped with contemporary imaging technology allows us
to see the lungs very clearly. Plus, we can use inhaled oxygen as a contrast
agent. This lets us study the structure and the function of the lungs much
better.”

The
researchers modified a commercial MRI system, Siemens Healthcare’s MAGNETOM
Aera, with a magnetic field strength of 1.5T to operate at 0.55T, while
maintaining the modern hardware and software needed for high quality images.
Researchers first tested the new imaging procedure using objects that mimic
human tissues, then quickly applied the procedure to healthy volunteers and
patients with disease.

“This
research helps us to define new strategies that may improve accessibility and
affordability of MRI as an imaging modality,” said Dr. Arthur Kaindl, head of
Magnetic Resonance at Siemens Healthineers. “We believe the high-performance,
low-field MRI will have a great impact on clinical care.”

When
compared with images obtained at 1.5T, researchers saw lung cysts and
surrounding tissues in patients with lymphangioleiomyomatosis, or LAM, more
clearly. In addition, researchers found that inhaled oxygen could increase the
brightness of lung tissue more effectively using the lower magnetic field
strength when compared to the higher field strength. These results show how
useful low-field MRI can be in helping identify problems in the lungs.

Researchers found similar advantages using low-field MRI during heart catheterization, a procedure used to diagnose and treat some heart conditions, but which has been hampered by the unavailability of suitable devices for MRI.

The new
generation of low-field MRI allows increased flexibility in image acquisition,
said Campbell-Washburn, and researchers can apply the technology for new
clinical applications that could change how MRI is used in the future.

“We can
start thinking about doing more complex procedures under MRI-guidance now that
we can combine standard devices with good quality cardiac imaging,” said
Campbell-Washburn, who noted that the results are also encouraging for imaging
of the brain, spine, and abdomen. Imaging the upper airway with this system,
she said, may also offer valuable clinical information for both sleep and
speech disorders.

Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics.

Redesigned MRI holds promise for the diagnosis and treatment of diseases.

ताजा समाचार/आलेख

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Redesigned
MRI holds promise for the diagnosis and treatment of diseases.