MRI utility may expand in interventional arena

Cheaper MRI isn't the only answer to growing health-care costpressures. While there is little doubt that MR system prices willstay level or drop as reimbursement is trimmed in the U.S., equipmentdemand may be strengthened by redefining the modality or "changingthe game," said Paul J. Mirabella, MRI general manager forGE Medical Systems.

"We will be introducing some game changes over the nextcouple of years," Mirabella told SCAN. "One exampleinvolves the use of both higher temperature (superconducting)technology and open (magnet) design in conjunction with interventionalradiology. Today no one is dealing with the interventional MRenvironment."

Health-care productivity has been helped in recent years bythe growth of minimally invasive surgical techniques. MRI couldboost the effectiveness of these therapies by providing enhancedplanning, guidance, monitoring and control, according to MorryBlumenfeld, general manager for minimally invasive therapy projectsat GE.

GE is investigating MRI-assisted therapy opportunities in suchareas as cryogenic, heat and laser surgery. The imaging vendorwill work with third-party suppliers in therapy areas outsideits technical expertise, he said. For instance, GE is lookinginto the use of MRI with Cryomedical Sciences' minimally invasivecryosurgical technology.

Cryosurgery involves the use of liquid nitrogen circulatedthrough percutaneously inserted cryoprobes to freeze and destroycancerous tissue. CMS of Rockville, MD, introduced its Accuprobecryosurgical device in June 1992 and sold 35 systems during itsfiscal year that ended June 1993. Over 800 procedures have beenperformed in the U.S., the company said this month.

GE will work with smaller therapy firms in proving the effectivenessof MRI-assisted procedures and in developing such prerequisitesas MRI-compatible instrumentation, Blumenfeld said.

Improvements in MRI speed, through developments such as echo-planarimaging, make the modality competitive with fluoroscopy and CT,while MRI offers visualization superior to other imaging technologies,he said. For instance, MRI could provide real-time monitoringof temperature changes in tissue during heat surgery. Reversibleheat pulses could also be seen by MRI for localization of subsequentlethal pulses.

GE also plans to add value by integrating the therapy and diagnosticsystems. Current closed-bore magnets limit the flexibility ofMRI for many interventional applications, according to MichaelR. Mainelli, product marketing manager for GE's Signa Advantage1T MRI system (SCAN 7/28/93). GE is exploring open systems toovercome these limitations.

"In order to do some MR biopsies in a conventional magnetyou have to set a frame reference and then take (the patient)out and do it outside, register it, and go back in," Mainellisaid.

While GE doesn't expect to become a catheter firm, there aretherapy areas where the vendor could add significant value. GEmay move more directly into the manufacture of therapeutic systemswhere it possesses expertise, Blumenfeld said.

One area under exploration is MRI-guided focused ultrasoundsurgery. GE has built up ultrasound expertise through its ultrasoundimaging business that would be useful in developing therapeuticapplications. Other vendors, such as Diasonics (see story, page2), are developing ultrasound ablation technology but not usingMRI guidance, he said.

MRI guidance has an advantage over ultrasound in providingmonitoring and control of procedures as they take place, he said.GE is also using focused ultrasound technology that is differentfrom Diasonics' and has targeted benign breast disease, ratherthan prostate disease, for the technology's initial applications.

Researchers from GE and Brigham and Women's Hospital showedresults from initial focused ultrasound research at the Societyof Magnetic Resonance in Medicine meeting in New York this month.

GE's objective--if it decides to proceed with the ultrasoundtherapy program--will be to supply an integrated MRI/focused ultrasoundtable, Blumenfeld said.

BRIEFLY NOTED:

• Alliance Pharmaceutical of San Diego received FDA approvalthis month for U.S. sale of its first perflourocarbon-based MRIcontrast agent, Imagent GI (SCAN 2/28/90). Imagent GI is an oralagent containing no hydrogen so that it produces a dark imagewhen scanned by MRI. This helps distinguish the bowel from adjacentorgans.

The potential U.S. annual market for Imagent GI was estimatedby the company at $35 to $50 million, although commercial prospectsmight decline with increased cost pressures on MRI. Picker HealthCare Products will distribute the agent.