Open MR is dead . . . Long live open MR

Open MR has confounded reason for a long time. The trouble began in late 1999, when GE unveiled its OpenSpeed, a 0.7T system that the company framed as a high-field system. Its vertical field provided enough oomph to compete with high-field products; ergo, the classification as "high field." Then came Siemens a few weeks later at the RSNA meeting with a mock-up of a 1T scanner, a truly open high-field system, according to the company. But the mock-up proved to be more concept than concrete, and now, a little more than four years later, Siemens has formally given up the idea of developing a clam-shaped 1T open scanner.

On July 29, Siemens rolled out its answer to customers who want a high-field MR for patients afraid of tight spaces and others too big to fit in them. Siemens' answer is a cylindrical system-a large-bore ultracompact doughnut that looks more like a CT than an MR. For 60% of routine exams, the patient's head will actually be outside the magnet.

The company, which previously had a proclivity for naming MR scanners with musical whimsy-Symphony, Sonata, Harmony, Allegra, and Concerto-would have the imaging community whistling a different tune over its new large-bore Espree. Open MR, as it has been known up to this point, is pretty much over. Enter now "open-bore" MR.

Focusing on ultracompact large-bore MRs to make patients more comfortable makes a lot of sense. And Siemens is to be applauded for taking this concept to a new level. But the idea that Siemens has so successfully built upon is really not all that new.

Companies have been racheting down the footprint of their magnets for a dozen years. This last year they began widening the bore. The Espree does both of these better than any other system on the market, but does that mean it rates a whole new class of scanner?

This presents a heck of a quandary. The imaging community will have to decide whether to define open MR as a concept that provides patients with the feeling of openness or as a type of scanner that is open on three or more sides. It's a sticky wicket and it's only going to get stickier when the inevitable happens: The trend toward wider bore ultracompact systems continues, and competitors to the Espree will start popping up.