Rapid Back Projection Reconstruction

Although volume visualization is an area of continuing progress, there is another need that is growing with new types of imaging techniques: visualization of a 3D structure using a set of projection images, i.e., images acquired from different orientations. Concerns of exposure to radiation and the need for high speeds make projection images a preferred mode of acquisition for some applications. Such requirements may be difficult to meet while acquiring the images in 3D mode. In this case, if the geometric nature of the object is known, a representative shape of the object can be reconstructed using image back-projection techniques. Although this principle is similar to the tomographic reconstruction used in CT, lack of sufficient accuracy and angular resolution may restrict the use of such approaches. Back-projection refers to a graphic technique in which a raster or scan line of an image is

FIGURE 8 3D visualization of intravascular MR probes obtained using real-time MR fluoroscopy imaging. Depth projection (third image from the left) is reconstruction from coronal and sagittal projections and shown registered with MR road-map images for navigating the probe.

FIGURE 9 3D reconstruction of brain fiber from diffusion tensor imaging. (Left) White matter tracts that form the corona radiata are shown: corpus callosum (yellow), anterior talamic radiation (red), corticobalbar/cortiscospinal tract (green), optic radiation (blue). (Right) Association of fibers and tracts in the limbic system is shown: cingulum (green), fimbria (red), superior (pink) and inferior (yellow) longitudinal fasciculus, uncinate fasciculus (light blue), and inferiour fronto-occipitial fasciculus (blue). See also Plate 115. (Images courtesy of Susumu Mori, R. Xue, B. Crain, M. Solaiyappan, V. P. Chacko, and P. C. M. van Zijl.)

FIGURE 9 3D reconstruction of brain fiber from diffusion tensor imaging. (Left) White matter tracts that form the corona radiata are shown: corpus callosum (yellow), anterior talamic radiation (red), corticobalbar/cortiscospinal tract (green), optic radiation (blue). (Right) Association of fibers and tracts in the limbic system is shown: cingulum (green), fimbria (red), superior (pink) and inferior (yellow) longitudinal fasciculus, uncinate fasciculus (light blue), and inferiour fronto-occipitial fasciculus (blue). See also Plate 115. (Images courtesy of Susumu Mori, R. Xue, B. Crain, M. Solaiyappan, V. P. Chacko, and P. C. M. van Zijl.)

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