MRI: New Attractions Prove Magnetic
MRI designers are thinking out of the box these days, with the innovative fruits of their creation such as open bore and big bore configurations, and higher field strength scanners, including 3Tesla (3T) and above, taking center stage at last week's Radiological Society of North America meeting. New and upgraded systems showed that improving patient comfort does not compromise image quality, and on the flip side, higher field strengths aren't just for research anymore.
Both Siemens and Philips featured a large bore and open bore MR system, respectively, emphasizing that patient comfort as well as hard-to-scan patients benefit from the newer designs. GE had some MR highlights of its own, most notably new technology that improves MR imaging speed and quality, as well as a non-invasive alternative to tumor ablation using MRI.
Toshiba showed new enhancements and applications for its Vantage ultra-short-bore 1.5-tesla scanner. Upping the total to four, the company introduced two new gradient packages for the scanner that increases its power and flexibility for users.
Scanners were not all the MR buzz at the show. Developer of MRI audio/video entertainment Resonance Technology introduced a virtual reality system that patients can wear during an MRI scan to improve their scanning experience. And in its first visit to RSNA, Everbrite Lighting Technologies introduced an alternative lighting technology designed specifically for MRI suites.
(Note: companies appear in alphabetical order.)
GE Healthcare launched new high definition MR (HDMR) technology for the GE Signa 1.5T and 3T systems that improves MR imaging speed and quality. It provides better image clarity in cases where patients are difficult to image due to movement, including Parkinson's patients who suffer from uncontrollable patient motion and including children who are not candidates for sedation, GE said.
HDMR enbles simultaneous imaging in multiple channels in increments of 16, according to GE. It features an acquisition architecture with individual receive channels connected to dedicated reconstruction engines. As channels are added (in units of 16, 32, 48, 64 and more), image processing power increases in proportion. The coil elements that detect the signal, the receivers that digitize it and the array processors that perform calculations are scaled together so that simultaneous imaging can be performed without image processing delays.
Built on GE's Excite platform of electronics and data-processing enhancements, HDMR is available on GE's Signa 1.5T and 3.0T MR systems. The company said HDMR will allow users to obtain vast amounts of data in a short amount of time and perform MR studies that would otherwise be compromised. Recent studies indicate 25 to 30 percent of all head MR studies are compromised by patient movement. GE's HDMR technology, Propeller, provides crisp images of the brain despite patient motion.
New targeted studies with HDMR include: extremely high resolution images of the liver with shorter breath holds and better organ coverage; MR echo real-time imaging of the heart with the resolution of MR at the speed of ultrasound, without the need for breath holding or ECG gating; and a new 32-element peripheral vascular coil, providing images of the lower leg and foot vessels.
GE and InSightec, a developer of non-invasive therapy systems, showcased at RSNA the ExAblate 2000MR guided focused ultrasound system. The system integrates focused ultrasound thermal ablation with GE's MR imaging capabilities to provide a non-invasive method for destroying targeted tissue.
The ExAblate 2000 attaches to GE's 1.5T MR scanner to identify tissues in the body, to assist in planning the treatment. During the procedure, delivery focused ultrasound energy is guided and controlled using MR thermal imaging. Thermal imaging feedback allows the physician to monitor and adjust the treatment to ensure that the targeted tumor is fully treated and all other tissues are avoided.
ExAblate 2000 received FDA approval in October for the use of non-invasive treatment of uterine fibroids. Future applications include breast, bone, liver and brain cancers.
"The idea is to take tumors and treat them with an energy source non-invasively," said Lynn Golumbic, marketing manager, InSightec. "The MR system provides very precise visualization of the tumor and all the other organs. It provides also a very clear view of the energy they get to make sure that no critical structures are hit. It gives real-time thermal feedback."
Golumbic said the selling price of the unit that attaches to GE's scanner is approximately $1 million. Current installations include Boston's Brigham & Women's Hospital and the Mayo Clinic.
Philips Medical Systems at RSNA launched its new Panorama 1.0T open, high field MRI system with active shielding. Providing patients will more comfort than closed MR systems, the system's high-field performance offers image quality comparable to that of a cylindrical 1.5T system, according to Pat McLellan, RN, practice administrator for Nevada Imaging Centers of Las Vegas, Nev. Nevada Imaging installed the first Panorama 1.0T open system.
Features of the Panorama 1.0T include: FastTrak patient handling (dockable table), an optional second table, integrated RF coil connections, patient communications and patient monitoring. The system's imaging capability is augmented with Philips' SENSE technology, the system's large field of view to 180-cm and its ability to perform off-center imaging. This ensures optimal image quality even for orthopedics, and orthopedic imaging helps to attract a large number of MRI referrals, said McLellan.
Installed at the free-standing imaging clinic for four weeks now, Pat McLellan and Garey McLellan, MD, medical director at Nevada Imaging, attended RSNA to share their experience. "The high field imaging quality actually gives imaging quality equal to a 1.5T system in my opinion," Pat McLellan said. "At the same, it provides patient comfort and that is a big demand from our patients. Not only is it for patient comfort, the open design allows us to image obese patients, claustrophobic patients, pediatrics and orthopedic and joint work."
According to Guido P. Stomp, global field marketing, director of MR, the Panorama 1.0T system will be available in the second quarter of 2005 and is priced about $2 million.
Philips also highlighted new enhancements to its Achieva 1.5T and 3.0T MR systems. In particular, Stomp stressed new ScanForum technology that incorporates ExamCards. This enables users to specify complete clinical studies with a single mouse click.
The Philips Achieva 1.5T offers complete applications in neurological, musculoskeletal and abdominal imaging, as well as functional and cardiac studies, contrast-enhanced angiography and spectroscopic imaging. The Achieva 3.0T MR system shares the same footprint as the Achieva 1.5T and brings high-field imaging into the clinical environment. New Quasar Dual gradients, developed specifically for 3.0T imaging, enable ultra-short TEs and sub-millisecond TRs. It combines 80 mT/m (milliTesla per meter) gradient strength and a slew rate of 200 T/m/s (Tesla per meter per second).
Philips introduced its MR NetForum Community website that takes user networks online and gives them access to clinical knowledge and expertise. Philips NetForum enables direct download of ExamCards to Philips MR scanners, including the Achieva family. Clinicians can browse through, select and directly download specific "recipes" for MR exams from a library resource contributed to by researchers, clinical users, and expert users around the globe. Philips NetForum is available to users 24/7.
As a works in progress, Philips exhibited the Panorama 0.6T I/T for interventional MR. Philips said its development of the system will broaden the clinical scope of Panorama 0.6T into the arena of MR-supported interventional procedures. The system offers the ideal platform for procedures that benefit from real-time visualization and monitoring by MR. Higher speed and resolution compared to lower field open systems will improve the accuracy of established interventional procedures, such as soft tissue and bone biopsies, drainages or nerve root infiltrations in the spine, and is likely to improve procedural outcome, the company said.
Siemens Medical Solutions was showing for the first time at RSNA its open-bore Magnetom Espree 1.5T MR system that debuted during the summer.
The 70-cm size bore allows for 60 percent of exams to be completed with the patient's head outside the magnet, said Lisa Reid, installed base manager, USA. The big bore design addresses imaging issues related to obesity, claustrophobia, elderly and pediatric patients.
In addition to image quality and the system's high signal-to-noise ratio, Reid said the system is available with TIM (total imaging matrix) technology. TIM is Siemens whole body surface coil design that combines up to 76 integrated coil elements with up to 32 RF Channels.
According to Reid, the system is installed at two sites. Siemens will begin delivering the Magnetom Espree in February. The system is priced in the range of $1.6 million to $2 million, depending on configurations, Reid said.
Siemens also announced that its Magnetom Trio system capable of 3T whole-body MRI will be available with TIM technology. The Magnetom Trio joins Siemens line of MR systems with TIM technology - the Magnetom Espree and the Magnetom Avanto, a 1.5T MR system, which was also on display at the show.
With the inclusion of TIM, Siemens said the Magnetom Trio significantly reduces the need for patient repositioning and manual coil changes, while providing potentially enhanced image quality. Suited for clinical or research MRI of all organs and all body regions, the Magnetom Trio opens new doors to applications, including abdominal, cardiac, spine, whole-body and orthopedic MRI at 3T.
Toshiba America Medical Systems at RSNA demonstrated at new software for its Ultra open-MRI system. Version 5.0 software includes advanced MRI pulse sequences that offer additional clinical versatility with faster scan times for Toshiba's open-MRI system.
The addition of new software expands the Ultra's clinical capabilities with the latest MRI pulse sequences, including: Super FASE, Steady State Two Echoes (SS2E) for high contrast imaging, which is similar to Steady State Free Precession (SSFP); Steady State T2 (SST2) for conducting heavily weighted T2 images; Sliding Slab for enhanced 3D TOF (time-of-flight) brain MR angiography images; Variable No Phase Wrap (NPW); Line Scan Diffusion to complement Single Shot Echo Planar Imaging (SS-EPI); and Swirl Encoding to reduce the flow and motion artifacts.
TAMS also introduced new gradient packages for the Excelart Vantage 1.5T MRI system that address a theme of "power and flexibility," said Bob Giegerich, director MRI and nuclear medicine business units. The Vantage MGV and the works-in-progress ZGV feature gradient strengths of 30 mT/m and 33 mT/m and slew rates of 86 mT/m/sec and 200 mT/m/sec (milliTesla per meter per second), respectively, were developed to address varied clinical imaging requirements.
Additional MRI applications offered on the system include optional packages for cardiac imaging, advanced echo planar imaging (EPI), perfusion and diffusion imaging, peripheral MR angiography (MRA), and SuperFASE (Fast Advanced Spin Echo) imaging.
With Toshiba's patented PianissimoTM technology, which effectively reduces acoustic noise by as much as 90 percent, TAMS said its Vantage reduces the most significant causes for patient discomfort and enables clinicians to better utilize the system's high-field MRI capabilities and SPEEDER parallel processing for increased imaging acquisition speed and reduced exam times.
A HELPING HAND FOR MRI
RSNA newcomer Everbrite Lighting Technologies used the show to springboard its MedLux family of lighting products designed specifically for MRI suites.
Everbrite's MedLuxGPI (graphic panel illuminator) uses high-quality 100,000-plus hour LEDs (light emitting diodes) to increase uptime and decrease maintenance costs. Everbrite said the lighting system is superior to fluorescent and incandescent lighting.
The GPI lightboxes replace standard 2-inch x 2-inch acoustical ceiling tiles, making it easy to evenly illuminate patient comforting graphics. While ceiling artwork has become common in MRI suites, Everbrite said the current fluorescent and incandescent lighting technology poses problems such as short life and interference with scans.
Additional benefits of the technology include low energy consumption, minimal UV or IR emissions to alter graphic panels as well as no electromagnetic interference emissions, Everbright said.
Medrad Inc. at RSNA introduced an 8-Channel Neurovascular Array Coil that provides high signal-to-noise imaging for full head and neck exams. The coil, which incorporates Medrad's patented phased array technology, and is designed for use with GE Healthcare's Excite 1.5T MR system, can be used for brain, vascular MRA and C-spine imaging.
According to Joanne M. Hoener, RT, MR technical support specialist for Medrad, the coil is ASSET (array spatial sensitivity encoding technique) compatible. The GE technology is an ultra-fast MR imaging technique that uses the unique geometry of phased array coils to spatially encode the image faster. ASSET can be used to scan faster, improve spatial resolution or increase coverage.
Medrad featured its Spectris Solaris EP injection system with increased battery capacity and a design that enables it to operate with 3T and open MR systems, in any proximity to the magnet. According to Shonda Butler, associate product manager, Infusion Systems MR, customers now have the option of purchasing an integrated Continuous Battery Charger (iCBC). The feature is suited for high-volume users who require the flexibility of battery or AC power charge mode.
Medrad also brought to the show its flagship Continuum MR Compatible Infusion system that was introduced in 2002. Protected with shielding material, the infusion pump can be brought into the MR imaging environment so that patients can continue infusion treatment therapy during their scan. Butler said the newest feature to the system is a syringe holder that can hold up to three standard syringes ranging in size from 20 to 60 mL. The syringe holder makes it possible to deliver small volumes of cardiac stress agents, IV sedatives and other medications during an MR procedure.
Resonance Technology Inc. debuted the latest in its digital laserlink MRI audio/video entertainment equipment.
CinemaVision, an internet based MRI-compatible system, can remotely monitor an MR procedure to detect problems and prevent malfunctions. With the technology, patients can see technologists during the scanning process through the Cinema virtual reality system, stereo sound can be adjusted by patients directly from within the magnet bore and technologists can select their own virtual entertainment during the scan process, independent of patient choices.
CinemaVision includes a head-mounted device that fits standard and 8 channel headcoils. The system also includes an MRI-compatible audio system with a two-way intercom. Set up time is minimal, said Mokhtar Ziarati, president of Resonance. Ziarati added that the system, which sells for $38,000, will begin shipping in January.
Serene Sound allows patients to listen to audio during a MRI procedure. The system features selectable audio sources for both patient and operator. The integrated entertainment console allows for easy upgrade to Resonance's CinemaVision. The FDA approved system sells for $8,700 and also will begin shipping in January, Ziarati said.