Imaging time

Fig. 3.4. Schematic diagram ofthe imaging time-of-flight SSIMS system used at the University of Munster, Germany.

The sensitivity and specificity of DWI depend to some extent on the technique being used and the amount of imaging time that can be dedicated to the DWI sequence. DWI pulse sequences typically require between approximately 30 seconds and 4 minutes of imaging time to image the entire brain and achieve sensitivity and specificity approaching 100% (Fig. 2.2). The rare infarcts that are not apparent on DWI are usually very small and are often located in the brainstem. 

Our method is demonstrated with experiments on a Bentheimer sandstone sample. The sample was prepared to be cylindrically shaped with a diameter of 2.5 cm and a length of 2.0 cm. The sample was fully saturated with de-ionized water under vacuum. We performed the CPMG imaging experiment described in the previous section to measure the magnetization intensity at 50 echoes spaced by 4.6 ms for each of 32 x 16 x 16 voxels within the field of view of 3.0 cm x 3.0 cm x 3.0 cm. The corresponding voxel size is 0.938 mm x 1.88 mm x 1.88 mm. We used 1 s of repetition time (TR) and the total imaging time was 4.3 min. 

For experiments in hypoxia, use Parafilm to seal the plate during the imaging time (carried out in normoxia) to avoid equilibration of the oxygen levels. 

This work has recently been extended, again with a single Pd/Al2O3 catalyst pellet 69). The image time was reduced to 34 s by introduction of manganese ions into the... 

Sjovall, P., Lausmaa, J., Nygren, H., Carlsson, L., and Malmberg, P. (2003). Imaging of membrane lipids in single cells by imprint-imaging time-of-flight secondary ion mass spectrometry. Anal. Chem. 75 3429-3434. 

Evaluation of Substrate d -Luciferin Distribution by In Vivo Imaging Time Course... 

Figure 12 Stigmatic imaging time-of-flight instrument of Schueler et al. (From Ref. 55.)...

Our typical MR protocol for suspected CVST includes an axial FLAIR, axial diffusion-weigh ted MRI, coronal T1 SE and T2 TSE sequences, a coronal gradient echo and a 3D phase contrast venous angiogram with a total imaging time of approximately 20 min. 

Regarding the energy emission of diagnostic radiopharmaceuticals, the finally produced y rays should be powerful enough to be detected from outside of the body of the patient. The ideal energy for nuclear medicine equipment is around 150 keV. y rays should be monochromatic and photon abundance should be high to decrease the imaging time. 

Fig. 7.8. PCSl showing the pattern of AIB translocation following addition to a wood block bait in a 25 cm square compressed-soil microcosm similar to that shown in Fig. 7.3. (A) Photograph of the mycelium at the time of adding C-A1B. (B-D) PCSl images. Time course, with time indicated on each picture. Compared with the sand-based microcosm shown in Figure 7.7, the AIB distribution appeared weaker and more diffuse. As in sand microcosms, there was preferential filling of only a few out of several cords present, and AIB was translocated from the point of application into the bait, and beyond it to an advancing mycelial front subtended by a cord.

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