[...]... aligning and superimposing images obtained using two different imaging modalities, is in fact a rapidly evolving field of interest In this chapter, we review the various approaches that investigators have pursued in the development of 3D ultrasound imaging systems, with emphasis on the steps of the process of making 3D sonographic images Moreover, an overview on US-CT/ MR fusion imaging will be included... VIBE images in a patient with colon carcinoma before (a) and after (b) the intravenous administration of gadolinium Multiple metastatic lesions are recognized and characterized in the VIBE images Fig 2.6 Coronal 3D spoiled gradient echo with fat saturation image obtained after the administration of a gadolinium-spiked water solution (1:100 proportion) The presence of gadolinium as an intraluminal contrast... sampled each time an image is rendered or re-rendered Volume rendering algorithms are attractive tools for displaying an image that synthesizes all the data contained in the numerical volume The most popular volume visualization algorithm for the production of high-quality images is ray-casting With the ray-casting approach a 2D array of rays is projected through the 3D image Shading and transparency... tissue shift correction in image- guided neurosurgery Med Phys 27:787–800 Crocetti L, Lencioni R, De Beni S, See TC, Della Pina C, Bartolozzi C (2008) Targeting liver lesions for radiofrequency ablation: an experimental feasibility study using a CT-US fusion imaging system Invest Radiol, in press Daly B, Templeton PA (1999) Real-time CT fluoroscopy: evolution of an interventional tool Radiology 211:309–331... probe housing An annular array producing a thin US beam can be accurately controlled by an internal mechanical motor in 2D to obtain a 3D volume with high resolution 2D probes can also be electronically steered within the image plane to increase the field of view (FOV), as in Rohling et al (2003) 1.3 Data Processing and Reconstruction The 3D reconstruction process involves the generation of a 3D image from... post-gadolinium evaluation, especially of small anatomic structures like the optical nerves (Fig 2.8) MP-RAGE is able to provide isotropic 1 mm resolution The sequence exhibits strong T1-weighting and is routinely utilized in clinical protocols for visualising cranial nerves before and after gadolinium injection, for imaging with very thin slices the pituitary gland, and for detecting congenital brain... contrast, especially in proton density and T2-weighted images Since the acquisition time is directly proportional to the repetition time, spin echo sequences are inherently time-consuming With the advent of gradient technology, fast or turbo spin echo (TSE) sequences were developed (Hennig 1986; Hennig 1988), significantly reducing the acquisition time while maintaining similar to spin echo contrast On... facilitates the segmentation process during virtual endoscopy post -processing and results in high quality virtual endoscopic views When combining volumetric T1weighted FLASH with a negative endoluminal contrast agent, such as an iso-osmotic water solution and intravenous administration of gadolinium, different enhancement patterns of involved segments with mural thickening can be demonstrated (Fig 2.7) The... motion: linear, tilting, and rotation (Fenster and Downey 2000) The linear scanning requires that the transducer is moved by the stepping motor in a linear fashion along the surface of the patient’s skin so that the 2D images obtained are parallel to each other The 2D images are acquired at a regular spatial interval that is adjusted to ensure appropriate sampling of the anatomy Because the 2D images... multi-planar reformation of volumetric data sets is incorporated in the clinical routine, resulting in more efficient management of hundreds or even thousands of images In this chapter, the most important 3D MRI pulse sequences commonly used in the clinical routine will be reviewed 2.2 Pulse Sequences Spin echo (SE) sequences are considered the gold standard in terms of image contrast A major limitation is the . tools in clinical workfl ow. The initial section of the book is dedicated to the technical aspects of image processing, from image acquisition to image processing in the 2D and 3D domain. A larger. targeting tech- nique during image- guided liver procedures include clear delineation of the tumor(s) and the surround- ing anatomy, coupled with real-time imaging and multiplanar and interactive. (MR) images by means of fusion imaging processes. Image fusion, the process of aligning and superimposing images obtained using two different imaging modalities, is in fact a rapidly evolving