Extraction of media and plaque boundaries in intravascular ultrasound images by level sets and min/max flow

. Estimation of plaque area in Intravascular ultrasound (IVUS) images after extraction of media and plaque-lumen interfaces is an important application of computer-aided diagnosis in medical imaging. This paper presents a novel system for fully automatic and fast calculation of plaque quantity by capturing the surrounding ring called media. The system utilizes an algorithm that consists of an enhanced technique for noise removal and a method of detecting different iso levels by sinking the image gradually under zero level. Moreover, an important novelty with this technique is the simultaneous extraction of media and lumen-plaque interfaces at satisfactory levels. There are not higher dimensional surfaces and evolution of contours, stopping at high image gradients. Thus, system runs really fast with curvature velocity only and has no complexity. Experiments also show that this shape recovering curvature term not only removes the noisy behavior of ultrasound images but also strengthens very weak boundaries and even completes the missing walls of the media. In addition to that, lumen-plaque interface can be detected simultaneously. For validation, a new and very useful algorithm is developed for labeling of IVUS images, taken from video sequences of 28 patients and a comparison-based verification is done between manual contours of experts and the contours extracted by our system.