Catheter takes MR imaging inside the body

MRI manufacturers responded to claustrophobic patients by developing open scanners. Now researchers have gone one step further: They've developed an MR scanner that enters the patient, rather than vice versa.

TopSpin Medical based in Israel has developed a miniature handheld probe that incorporates all magnetic field sources and delivers high-resolution MR images. The disposable intravascular catheter is intended for interventional cardiologists. Its primary application is to detect vulnerable coronary plaque.

"It is known that 70% of acute coronary syndromes are caused by vulnerable plaques, which are not angiographically significant and are undetectable by available imaging tools. Using the intravascular MRI catheter in a cardiac catheterization procedure will allow the detection of lipid-rich vulnerable plaques, characterization of plaque composition and geometry, and therapy guidance," said Eyal Kolka, senior vic president of business development for TopSpin.

Advantages of this technique include its low cost ($1000, with no expensive external setup), elimination of motion artifacts, accessibility to the patient during the procedure, compatibility with existing interventional tools, and resolution and diffusion contrast capabilities that are unattainable by conventional clinical MRI, according to Kolka.

The catheter is stabilized in relation to the arterial wall by gentle inflation of a low-pressure (up to 1 atmosphere) side balloon. The catheter's resolution of 100 microns (0.1 mm) is three to five times better than state-of-the-art cardiac MR scanners, which achieve 300 to 500 microns (0.3 to 0.5 mm).

Other potential applications include detection and staging of prostate cancer, imaging tumors in the colon, lung, and breast, and imaging the peripheral vasculature, Kolka said. Clinical trials have begun in Europe to assess the safety and performance of the intravascular MRI catheter, and the device is expected to be released in 2005.

For more information from the Diagnostic Imaging archives:

MR perfusion determines degree of coronary stenoses

Cardiac MR perfusion - with some help - assesses coronaries

Stat attack in cardiac

CT and MR gain ground in plaque detection