Image acquisition techniques

Initially, drop coordinate points had to be obtained by some manual procedure. In the early 1990s, Cheng et al. (37) developed an enhanced digital image acquisition technique for extracting the drop profile coordinate points from the images of experimental drop... 

CTP is a relatively recent development in acute stroke imaging that is already in routine clinical use in many centers. CTP and MRP are similar in that both techniques are based on rapid serial image acquisition during intravenous injection of a bolus of contrast material. In both techniques, measurements of density over time (for CTP) or signal intensity over time (for MRP) are converted to contrast agent-versus-time curves, and these are processed in similar ways to yield the same perfusion measurements (most often CBV, CBF, and MTT). Example CTP images are shown in Figure 2.12. 

Thus, we see that in a single image acquisition, the line excitation SEMI-RARE method allows an evaluation of the extent of flow heterogeneity (up- and downflow) within the monolith. Furthermore, velocities in completely liquid field channels can be measured. This was not possible when SEMI-RARE was used because velocities were measured by following a gas-liquid interface. However, a limitation of the line excitation SEMI-RARE technique is that there needs to be a significant amount of liquid present within the monolith, because the gas phase is not imaged only liquid captured in the initial line excitation can be followed. 

For a particular biomedical application of CRS microscopy, the best choice whether to use CARS or SRS detection depends on the optimal balance between the pros and cons of each technique regarding its detection sensitivity, image acquisition time, and interpretability of image contrast and spectrum. In the following, we provide a critical discussion of the advantages and disadvantages of both complementary detection techniques ... 

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