Volcano Therapeutics, a maker of IVUS machines, is testing a new version that uses sophisticated software to quickly determine plaque composition and volume.

FORBES: Peeking at Plaque

Nissen's studies use a technique called intravascular ultrasound (IVUS), which measures the volume of plaque in a coronary artery using an ultrasound probe inserted through a catheter.

FORBES: Pfizer's Lipitor Stops The Plaque

New catheter-based imagers aim to improve IVUS by letting doctors distinguish stable plaque, safely ensconced in scar tissue, from the inflamed plaque that is more likely to rupture and trigger a heart attack.

FORBES: Peeking at Plaque

One of the worst cases occurred in September 2004 when the tiny biotech firm Atherogenics had to call in Nissen to help reinterpret results of a troubled IVUS study that suffered from data quality problems.

FORBES: Magazine Article

For other heart medicines that don't affect cholesterol levels, like a drug being developed by Japan's Sankyo to keep plaque from sticking to the artery wall, IVUS may be the only way to evaluate effectiveness.

FORBES: Peeking at Plaque

There is not as of yet a clinically proven link between plaque measured with IVUS and heart attacks, and IVUS can only be done in patients whose cardiovascular disease is so severe that they need a catheter for another reason.

FORBES: Pfizer's Lipitor Stops The Plaque