Multi-slice imaging

If the region of interest in the sample is not well defined, it is advantageous to acquire more than one slice through the object. Effective use of instrument time is achieved by 

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Fig. 6.2.7 [Fral] Timing diagram for multi-slice imaging by the STEAM method. The third rf pulse is used for slice selection. It is repeated with different centre frequencies for acquisition of different slices.

A closely related technique can be used for multi-slice imaging (Fig. 6.2.7) [Fral]. The scheme of Fig. 6.2.5(c) is appended by further slice-selective 90° pulses with different centre frequencies, so that the magnetization of other slices is selected [Fral]. In this way, the otherwise necessary recycle delay can effectively be used for acquisition of additional slices. However, the contrast in each slice is affected by a different Ty weight, because is different for each slice. The technique can readily be adapted to line-scan imaging by applying successive slice-selective pulses in orthogonal gradients [Finl]. 

Fig. 2.1.16 Trabecular bone structure, muscle after removal of the soft tissue (right). Image and tendon of a mouse tail in vitro at 21.14T, parameters multi-slice spin-echo method,...

We have developed a software package MSLS [1], in which multi-slice calculation software is combined with least squares refinement software used in X-ray crystallography. With multi-slice calculations which are standardly used for image calculations of HREM images, dynamic diffraction is taken into account explicitly. 

Perform three orthogonal sets of multi-slice T2-weighted FSE images to assure appropriate head position and good acoustic coupling. 

Fig. 5.3.13 Hadamard encoding and decoding for simultaneous four-slice imaging. The encoding is based on four experiments, A-D. In each experiment, all four slices are excited by a multi-frequency selective pulse. Its phase composition is determined by the rows of the Hadamard matrix H2. The image response is the sum of responses for each individual, frequency selective part of the pulse. Thus, addition and subtraction of the responses to the four experiments separates the information for each slice. This operation is equivalent to Hadamard transformation of the set of image responses. Adapted from [Miil21 with permission from Wiley-Liss. Inc., a division of John-Wiley Sons, Inc.

Fig. 7.2.7 [Haa3] Multi-CHESS-STEAM imaging, (a) Simultaneous acquisition of one nonselective HE image and n CHESS-STEAM images from one slice, (b) Multi-slice double CHESS-STEAM method for simultaneous acquisition of two CHESS images at n slices.

In this paper, we review the determination of the shape and the structure of metal particles by electron microscopy as illustrated by examples of Pd clusters epitaxially oriented on oxide single crystals and thin films of MgO and ZnO. The metal-oxide interfaces are characterized by HRTEM profile-view imaging, numerical analysis of the images, and image simulations by the multi-slice technique. 

The HRTEM images of the particles annealed under UHV or in low pressures (10 torr) of O2 show that the junction between the (111) and (100) faces is sharp. Comparison of the experimental images with images simulated by the multi-slice technique shows that this junction is atomically sharp. On annealing at higher pressures (10 torr) progressive rounding occurs at the corners this is completely reversible by reduction in H2. 

The multi-slice technique of H MRI was used to study regional effects of amphetamine on rat brain [49], a two-coil system enabling three-dimensional perfusion imaging. Amphetamine caused a significant increase in perfusion in many areas of the brain, including the cortex, cingulate and caudate putamen. 

Fang C.C., Jao Y.T., Han S.C., Wang S.P. (2007) Persistent left superior vena cava multi-slice CT images and report of a case. Int Cardiol 121 112-114. 

Rodt T, Ratiu P, Becker H et al (2002) 3D visualisation of the middle ear and adjacent structures using reconstructed multi-slice CT datasets, correlating 3D images and virtual endoscopy to the 2D cross-sectional images. Neuroradiology 44 783-790... 

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