Siemens offers kinder, gentler MRI

Siemens hopes that MRI scans will be less traumatic for sensitivepatients as a result of a noise reduction system being offeredon an exclusive basis by the German vendor.

The system is the only active MRI noise cancellation techniqueon the market and Siemens has an exclusive two-year license tomarket it, according to Irene Lebovics of Noise Cancellation Technologies(NCT) of Stamford, CT, the developer of the system.

NCT had originally planned to work with center firm TME ina joint venture to apply noise cancellation technology to MRI.That effort fell apart three years ago. One of the first MRI customersfor NCT's product was Diasonics, the primary supplier at thattime of MRI systems used in TME centers (SCAN 9/27/89).

NCT's system reduces by 15 to 20 decibels the noise causedby gradient switching during MRI scans. This makes patients morecomfortable and in turn can lead to improved MRI efficiency becausefewer patients cancel procedures, according to Anne Deery, MRIcommunications manager for Siemens Medical Systems.

"The noise can be startling, and there is a healthy numberof cancellations," Deery told SCAN. "(Even) people whotolerate (the noise) will be hesitant to go again."

MRI noise is the second most common reason for scan cancellations,after claustrophobia, Lebovics said. A patient undergoing MRIcan experience 85 to 105 decibels of noise, a range comparableto the noise produced by a jackhammer or experienced in the interiorof an airliner during takeoff.

The NCT system works by analyzing sound waves produced by theMRI unit and electronically creating an "anti-noise"waveform 180´ out of phase with the original sound wave.When the two waves meet, the loudness of the original noise issubstantially reduced. Patients perceive 70% to 90% less noisewith the system in use, Lebovics said.

The technique is superior to passive systems like stereos,which are sometimes given to patients to drown out gradient noisebut do nothing to reduce sound levels, Deery said.

"That's adding noise to noise," she said.

The NCT units cost $17,000 if purchased individually, but Siemensis offering them without charge on all Magnetom MRI packages.Each unit comes with a headset and stereo so patients can listento music or hear communication from the technologist during thescan.

The noise cancellation units will be available in June. Thesystem should be a good selling point for Siemens MRI systems,Deery said.

"It's one of a couple of little things that set our unitsapart," she said.

Siemens could be the only company with an active noise reductionsystem for several years, as NCT has a wide range of patents onactive MRI noise cancellation technology, according to Lebovics.

"Our intellectual property in this arena is very strong,"Lebovics said. "We feel we'll be the only player in thismarket for some time."