The FDA has granted 510(k) clearance to InfraReDx Inc. of Burlington, Mass., to market its catheter-based LipiScan coronary imaging system. The device uses near-infrared spectroscopy to identify lipid-core-containing plaques in the coronary arteries of patients undergoing cardiac catheterization. These plaques, which cannot be detected by commonly used tests, are suspected of causing sudden cardiac deaths and nonfatal heart attacks.