RT Image August 3, 2009 : Page 30
| SPECIAL FOCUS MRI Safety Can You Hear Me CASE STUDY NOW? TECHNOLOGY FOR BETTER COMMUNICATION IN THE MRI SUITE BY SUSAN KARLIN A COMPLICATED ABLATION. A gingerly guided needle where a centimeter in the wrong direction can cause serious injury.The incessant metallic rattling of the MRI machine drowning all nuanced communication. Medical staff stumbles along with shouts, hand gestures, and written signs. At a critical point, the operator incorrectly hears the doctor tell him to turn off the scanner, and the image disappears. The patient remains in limbo, partially sedated. Procedure time is tripled. The doctors have to gather their thoughts before continuing. Thanks to a new optical fiber-based intercom system, MRI medical staff and patients at four U.S. hospitals can communicate better, increase production, and reduce risk. MRI noise and its workflow impediment have long been critical roadblocks to advancing interventional MRI (iMRI) from cutting edge to mainstream use. Since MRI came into wide use, noise reduction solutions have eluded acoustics engineers. And the problem is threatening to worsen as more powerful – and significantly louder – MRI machines come to market. To compound this situation, hospital management expects staff to increasingly expedite MRI procedures. Now, the Israel-based company Optoacoustics has tackled these issues with their Interventional MR Optical Communication System (IMROC™ ) and is transforming iMRI efficiency and safety in the process. The system’s fiber optic-based microphones and headphones enable normal conversation in MRI environments by reducing gradient noise and enhancing voices for as many as eight concurrent users. Fiber optic technology is safe for the MRI suite and does not interfere with the machine’s magnetic field and image clarity. “Doctors kept telling us that one of the biggest issues was a need for a communications system for iMRI – hand signals were not going to cut it if this technology was going be ready for prime time,” says Christine Lorenz, PhD, director of the Center for Applied Medical Imaging, Siemens Corporate Research, a Baltimore-based R&D group developing iMRI procedures that helped find interested hospitals but has no financial stake in Optoacoustics. “The noise of the MR scanner increases the complexity and risk, because iMRI procedures require a whole team to work in synchronization, which is hampered without good communication. The main benefit of the IMROC system is that there’s no more guesswork in team communication. Procedures are done more efficiently, and the patient spends less time in the scanner.” The IMROC system has gotten high marks from four early adopters – University of Texas M. D. Anderson Cancer Center in Houston; University of Utah School of Medicine in Salt Lake City; Johns Hopkins University School of Medicine in Baltimore; and the National Institutes of Health (NIH) – and changing the way they handle |30| August 3, 2009 interventional, intraoperative, diagnostic, and neurosurgical MRI. “We were off and running with it from day one,” says R. Jason Stafford, PhD, an imaging physicist working with a team using the IMROC for MR-guided interventions at M. D. Anderson. The center’s pioneering iMRI activities focus on MR-guided biopsies and ablations for the head, neck, soft tissue, bone, liver, and kidney. “Before we got this system, we trudged through the more complex procedures, and it was just painful. The radiologist would get frustrated with his inability to communicate properly. The noise made it difficult, cumbersome, and slowed the entire procedure down. “What IMROC did was enable everyone to do their job more rapidly and efficiently, and allow the technologist to return to where she belonged – in the driver’s seat of the MRI suite – without breaking the line of communication between the radiologist and technologist,” he adds. “It increases safety by improving momentum. There are no longer interruptions due to a lack of communication. It would probably be an excellent tool for teaching and facilitating communication between multiple teams working together in the MRI.” HEARING THE LIGHT IMROC’s key achievement is the integration of several breakthrough technologies into a single system. Noise reduction for MRI is vastly more complicated than simply dampening a set of noise frequencies, like the noise reduction headphones used on a jet flight. MRI noise is the product of constantly changing frequencies that reach as high as 120 dB (the equivalent of a jet engine on takeoff). Conventional technology solutions simply cannot be used, since they contain electronics or metal elements that would create safety issues and interfere in the MR imaging process. “MRI machines present one of the most complex problems of dealing with noise,” says Optoacoustics CEO Yuvi Kahana, PhD, an acoustics expert. “Not only do we deal with very high levels of noise, but also with difficult noise patterns – and these patterns change from scanner to scanner and from scan to scan. Finally, we’re collecting very similar noise from many microphones simultaneously. So we had to develop a system where each headset operates independently using a digital ‘brain’ that can determine whether it is collecting noise or speech.” To accomplish this, Kahana explains, each IMROC headset is paired with its own fully adaptive and automatic digital signal processor (DSP) chip and only sub- sequently are the various channels mixed in a central control unit. The IMROC is based on Optoacoustics’ core optical microphone technology, patented in the 1990s, which produces sound information by measuring changes in light waves. Light enters a microphone through one optic fiber and strikes a tiny membrane that is vibrating
CASE STUDY : CAN YOU HEAR ME NOW?