Functional Cardiac Imaging - Navigating the Fifth Dimension

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US Cardiology 2006;2005:2(1):1-4


During the last decade, three-dimensional (3-D) imaging has rapidly become an essential part of the visualization tools used in a variety of diagnostic procedures in radiology. With the latest generation of multi-detector computed tomography (CT) and magnetic resonance imaging (MRI) scanners it is possible to acquire high-resolution dynamic images of the heart in a single breath-hold. These studies provide isotropic data that have identical resolution in the three dimensions, providing exquisite detailed anatomical information. With 3-D volume rendering techniques it is possible to generate high-quality images offering a realistic anatomical view of the heart and vessels allowing the physicians and care providers to better visualize anatomical structures and morphological anomalies. Due to the inherent function of the heart it is necessary to be able to display the images in a dynamic mode adding a temporal dimension to the images. This dimension, often referred to as the fourth dimension, is obtained by acquiring images of the heart at different phases of the cardiac cycle allowing a better assessment of cardiac motion and function.

Another rapidly growing domain of medical imaging is the evolution toward functional and molecular imaging for the assessment of biological and metabolic pathways. Positron emission tomography (PET) using radio-labeled tracers represents the most common molecular imaging modality, but other techniques based on molecular markers are nowadays emerging in other modalities, such as MRI, offering new perspectives of functional imaging and a great hope to increasing the specificity and sensibility of diagnostics and detection of varieties of diseases. These modalities are complementary to classic conventional and anatomical imaging like CT and MRI. The ability to combine the functional or molecular data with the anatomical images adds a new dimension to the images. This functional or molecular component is often referred to as the fifth dimension.

TodayÔÇÖs physicians need new tools and new ways to explore these multidimensional data generated by modern imaging techniques. New software platforms need to be simple and intuitive and provide extremely fast and powerful processing capabilities allowing the users to easily navigate and explore complex anatomical and functional features of these examinations.

This is the main rationale behind the development of a new generation of image navigation tools that is more suitable for multidimensional datasets. The OSIRIX software developed by collaboration between University of California, Los Angeles and the University of Geneva is one of such software platforms that allow users to efficiently and conveniently navigate through large sets of multidimensional data without the need for high-end expensive hardware. Most importantly, the system was also developed under the new open source paradigm based on the integration of existing open source software libraries and allowing other institutions and developers to contribute to this project.