3D and 4D Medical Image Registration Combined with Image Segmentation and Visualization

IntroductIon Image registration, segmentation, and visualization are three major components of medical image processing. Three-dimensional (3D) digital medical images are three dimensionally reconstructed, often with minor artifacts, and with limited spatial resolution and gray scale, unlike common digital pictures. Because of these limitations, image filtering is often performed before the images are viewed and further processed (Behrenbruch, Petroudi, Bond, et al., 2004). Different 3D imaging modalities usually provide complementary medical information about patient anatomy or physiology. Four-dimensional (4D) medical imaging is an emerging technology that aims to represent patient motions over time. Image registration has become increasingly important in combining these 3D/4D images and providing comprehensive patient information for radiological diagnosis and treatment. 3D images have been utilized clinically since computed tomography (CT) was invented (Hounsfield, 1973). Later on, magnetic resonance imaging (MRI), positron emission tomography (PET), and single photon emission computed tomography (SPECT) have been developed, providing 3D imaging modalities that complement CT. Among the most recent advances in clinical imaging, helical multislice CT provides improved image resolution and capacity of 4D imaging 3D and 4D Medical Image Registration paramagnetic resonance imaging (EPRI) (Matsunoto, Subramanian, Devasahayam et al., 2006). Postimaging analysis (image processing) is required in many clinical applications. Image processing includes image filtering, segmentation, registration, and visualization, which play a crucial role in medical diagnosis/treatment, especially in the presence of patient motion and/or physical changes. In this article, we will provide a state-of-the-art review on 3D/4D image registration, combined with image segmentation and visualization, and its role in image-guided radiotherapy (Xing, Thorndyke, Schreibmann et al., 2006).