Slice orientation

NMR Methods. Altobelli et al. (82) and Sinton and Chow (83) studied solid velocity and concentration profiles of flowing slurries using NMR flow imaging techniques. These profiles were obtained from the displacement of a tagged slice oriented perpendicular to the flow direction using fast Fourier reconstruction algorithms (83). 

For examinations on a multislice scanner, thin slices should be used to compute high-quality multiplanar reformations. However, for interpretation of the source images, the reconstruction slice thickness should not be less than 3-5 mm, regardless of the slice orientation. 

Reference Tesla Posilioning Type of sequence dynamic Single slice or slab Slice orientation Patient instruction Reference line Opacification ... 

For the dynamic studies the midsagittal cut through the pelvis is the most preferred slice orientation throughout the entire literature. It was first introduced by Yang et al. [49] and Kruyt et al. [25] and provides an excellent overview of all relevant organs within the different compartments of the pelvis and the bony frame. In addition, we are familiar with this kind of view since the days of conventional cystography or evacuation proctography. But in our opinion, for a sufficient depiction of the complexity of the pelvic floor, at least two different slice orientations perpendicular to each other are required. Opposed to this, in the literature coronal and axial slices are only occasionally used to achieve additional information [12,13,41,43]. 

Fig. 11.7a-d. Postoperative CT. Axial MPR (a-c), paracoronal MPR (d). Lines in c show the slice orientation of d. Normal CT after open mastoidectomy (a). Nearly completely opacified cavity after open mastoidectomy (b) in which CT can demonstrate the extension of opacities and situation along the walls of... 

The LITT treatment is performed under MR guidance using a 0.5 Tesla scanner (Privilig, Escint, Israel) by Tj-weighted GE sequences (TR/TE=140/12, flip angle=80°, matrix 128 x 256,5 slices, slice thickness 8 mm, interslice gap 30%, acquisition time 15 s) in axial slice orientation and parallel to the laser applicators. These two sequences are repeated every minute. Increasing tissue temperature results in an increase in the Tj relaxation time. Finally this results in a decrease of signal intensity (Fig. 2.3.5). 

The 3-D image within the reconstmction sphere, which has a radius of Ro, is obtained by summing all the images reconstmcted at each slice orientation in which a complete set of 2-D projection data is provided. This sum image should be divided by the number of slice orientations reconstmcted for normalization. Essentially, this is the basis of the reconstmction algorithm developed for tmncated spherical geometry. 

For the implementation of the algorithm, all slice orientations involved in each set of projection data must be identified and the corresponding composite filter function generated. In fact, each 2-D parallel projection data set corresponding to a certain object size has a fixed number of slice orientations. This allows us to treat a certain projection data set in a unified way that is, a 2-D projection data set can be processed with one filter function. Let us consider a 2-D projection data set projected on a direction parallel to the line 00 in Fig. 3. Here, Op is the center of the projection plane. As shown in the figure, these projection data are shared by slice orientations rotated around the line OOp from -/3 to /3, where... 

A two-dimensional slice may be taken either parallel to one of the principal co-ordinate planes (X-Y, X-Z and Y-Z) selected from a menu, or in any arbitrary orientation defined on screen by the user. Once a slice through the data has been taken, and displayed on the screen, a number of tools are available to assist the operator with making measurements of indications. These tools allow measurement of distance between two points, calculation of 6dB or maximum amplitude length of a flaw, plotting of a 6dB contour, and textual aimotation of the view. Figure 11 shows 6dB sizing and annotation applied to a lack of fusion example. 

There is of course no requirement to confine the slice selection to the z-gradient. The gradients may be used in any combination and an image plane selected in any orientation without recourse to rotating the sample. 

Fig. 1.18 A film of silicone oil of 1 mm thickness is flowing along a vertically oriented planer sheet of PMMA. In a tagging experiment, a horizontal slice of 2 mm thickness is marked and its deformation is recorded as a function of the separation time A between the...

Fig. 2.9.2 Radiofrequency, field gradient and current distributions requires a three-dimen-ionic current pulse sequences for two-dimen- sional imaging sequence [see Figure 2.9.1(a)] sional current density mapping. TE is the Hahn and multiple experiments with the orientation spin-echo time, Tc is the total application time of the sample relative to the magnetic field of ionic currents through the sample. The 180°- incremented until a full 360°-revolution is pulse combined with the z gradient is slice reached. The polarity of the current pulses...

As pointed out by Stribeck [139,171] g (x) is, as well, suitable for the study of oriented microfibrillar structures and, generally, for the study of ID slices in deliberately chosen directions of the correlation function. This follows from the Fourier-slice theorem and its impact on structure determination in anisotropic materials, as discussed in a fundamental paper by Bonart [16]. 

The term monolayer (ML) must be defined clearly. In the work presented here, two definitions are used for surface studies, one ML indicates one adsorbate for each surface atom. For studies of compound formation, a monolayer is a slice of the compound s crystal structure, composed of one atomic layer of each of the constituent atoms. This does not necessarily mean a one unit-cell thick deposit is formed, as most compounds have larger unit cells from the point of view of crystallography, dependent on the orientation (Figure 8). 

A variety of different types of tissue preparation are used to study neurosecretion and synaptic transmission. A classical preparation is the frog NMJ (discussed below). The brain slice has been used for many years for biochemical studies of CNS metabolism and is a useful preparation for electrophysiological studies of synaptic transmission in the CNS. Slices can be oriented to maintain the local neuronal circuitry and can be thin, 0.3 mm, to minimize anoxia. The transverse hippocampal slice is widely used as an electrophysiological preparation to study synaptic plasticity (see Ch. 53). Primary cultures of neurons from selected CNS areas and sympathetic ganglia are also frequently used. They permit excellent visual identification of individual neurons and control of the extracellular milieu, but the normal neuronal connections are disrupted. 

In addition, from ultrathin slices of the embedded material HRTEM images were obtained in different crystallographic orientations ([001] (see Fig.5), [101], [110], [-111], [102], [120], [201], [122], [203], [301], [1-19], [-124]). Using the structure model of Rius et al. the comparison of kinematically electron diffraction patterns have been compared with experimental data (Cerius 4.2 [8]) as shown in Fig. 6. The basic course of... 

---