Manifold Learning for Image-based Gating of Intravascular Ultrasound (IVUS) Pullback Sequences
Gozde Gul Isguder
Sabanci University Research Database
Intravascular Ultrasound(IVUS) is an imaging technology which provides cross-sectional images of internal coronary vessel structures. The IVUS frames are acquired by pulling the catheter back with a motor running at a constant speed. However, during the pullback, some artifacts occur due to the beating heart. These artifacts cause inaccurate measurements for total vessel and lumen volume and limitation for further processing. Elimination of these artifacts are possible with an ECG (electrocardiogram) signal, which determines the time interval corresponding to a particular phase of the cardiac cycle. However, using ECG signal requires a special gating unit, which causes loss of important information about the vessel, and furthermore, ECG gating function may not be available in all clinical systems. To address this problem, we propose an image-based gating technique based on manifold learning and a novel weighted ultrasound similarity measure. The parameters for our image-based gating technique were chosen based on the experiments performed on 25 different in-vitro IVUS pullback sequences, which were acquired with the help of a special mechanical instrument that oscillates with given length and frequency. Quantitative tests are performed on 12 different patients, 25 different pullbacks and 100 different longitudinal vessel cuts. In order to validate our method, the results of our method are compared to those of ECG-Gating method. In addition, comparison studies against the results obtained from the state of the art methods available in the literature were carried out to demonstrate the effectiveness of the proposed method.