Aurora adds spiral imaging to breast MR

Soon after the RSNA meeting, Aurora Technologies will begin routinely upgrading its installed base of about 20 dedicated breast MR scanners with a new type of acquisition capability that boosts signal-to-noise by 300%, according to the company.

The upgrade, called spiral RODEO (Rotating Delivery of Excitation Off-resonance), completely changes data acquisitions. Rather than acquiring data line by line, as happens in a conventional fat saturation 3D Fourier transformation, the new approach acquires data from the center of the field-of-view outward in a spiral pattern.

"With spiral RODEO, we are acquiring data 46% of the time compared to a typical fat-sat acquisition, which does so about 9% of the time," said Dr. Steven Harms, Aurora's medical director.

Current users of the 1.5T Aurora system will get the upgrade first. Facilities that order the breast MR system will receive spiral RODEO automatically, according to Debbie Thomas, vice president of marketing for Aurora.

"Our goal is to have all existing Aurora users upgraded starting right after the RSNA meeting and going into December and next year," she said. "Then we'll continue rolling it out for new orders. The earliest of these, if someone orders today, is February."

Spiral RODEO was cleared by the FDA almost a year ago and shown as a work-in-progress at the 2005 RSNA meeting. It entered clinical testing in June 2006 at the Breast Center of Northwest Arkansas in Fayetteville, a women's health center operated by Harms, who keeps one foot on the clinical side and the other on the corporate. Harms developed RODEO several years ago, while serving as the director of imaging research at the University of Arkansas in Little Rock.

RODEO allows fat-suppressed magnetization transfer. When applied after contrast injection, this proprietary pulse sequence reduces signal from normal ductal tissue and, thereby avoids false-positive enhancement from benign lesions and dense fibroglandular tissue, according to Harms.

The spiral version improves signal-to-noise by a factor of three, he said. This translates into dramatically improved acquisitions: 160 slices with images at 512 x 512 pixels.

"The big advantage is that this may more accurately distinguish DCIS (ductal carcinoma in situ) from benign changes," Harms said.

Images acquired at the Fayetteville imaging center show branching enhancement that is typical of DCIS, he said. This branching was apparent in "almost every single case of DCIS," he added.

"In our experience with 3D FT (conventional Fourier Transform acquisitions), we did not see branching enhancement that often," he said.

Spiral RODEO is a proprietary capability of Aurora - and it will very likely stay that way, according to Harms. Aurora's 1.5T scanner was specially designed with oscillating gradients to support this pulse sequence.

"To add this to another vendor's system would require taking the system apart and rebuilding it," Harms said. "And then all the other applications you had wouldn't work."