Proton imaging

Figure 16.11. Successive proton images of the spine of the same subject showing two different types of contrast. (Reprinted with permission from Wehrli FW, Shaw D, Kneeland JB, eds. Biomedical Magnetic Resonance Imaging. Principles. Methodology and Applications. VCH Publishers, Inc., Weinheim, Germany, 1988. Copyright 1988 VCH Publishers, Ine.)...

Figure 16.23. Proton image of the polymer in a crosslinked silicone polymeric block that contains in situ precipitated silica filler.

Figure 16.24. Proton image of the penetration of methanol into a square block of poly(methylmethacrylate).

Figure 16.25. Motion-sensitized proton images of water flowing in a tube. The top image gives the velocity (vertical direction) at each point in the tube cross section, the middle image gives the molecular diffusion coefficient, and the bottom shows the expected parabolic velocity profile across the tube diameter. (Reprinted with permission from Callaghan PT. Principles of Nuclear Magnetic Resonance Microscopy. Oxford University Press, New York, 1991. Copyright 1991 Oxford University Press.)...

Plate 19.7 Distribution of capecitabine and its metabolite FBAL in the liver of a patient treated with oral capecitabine at 3 T. (a) Spatially localized, 9F MR CSI spectra overlaid on the axial proton image of the liver acquired using the same surface coil, (b) and (c) Color depiction of distribution of FBAL in the axial plane and capecitabine in the coronal plane, respectively, (d) and (e) Distribution of FBAL in the coronal and axial planes, respectively, depicted by CSI spectra, (f) Distribution of water signal in the axial plane. 

Figure 19.8 Distribution of fIuvoxamine at steady-state concentration in the brain of a volunteer measured by 19F MR CSI at 3 T. (a) Spatially localized, 9F MR CSI spectra overlaid on the axial proton image of the brain and including the external reference sample., 9F spectra of a voxel containing (b) the background (e.g., no structure and no signal), (c) posterior brain tissue, and (d) external reference compound (trifluoroethanol). The density of the compounds is reflected by peak amplitude and area under the curve (AUC).

Fig. 8.7.3 Proton images (bottom) of a phantom made from poly (acetal) (Delrin) acquired with the time-suspension pulse sequence of Fig. 8.6.2, The field of view is (5.9 mm). The sample (top) has been imaged in three dimensions at 400 MHz with a voxel size of 92 x 92 x 625(pLtti). Adapted from [Corl2] with permission from Flsevier Science.

Proton NMR imaging was used to study the volume phase transition in a thermo-responsive hydrogel (Ganapathy et al. 2000). The thermally induced volume phase transition was clearly seen in the proton image. The shrinking of a polyelectrolyte gel under the application of an electrical DC field was observed in real time (Hotta and Ando 2002). 

In MALDI, quasi-molecular ions ([M+alkali]+ formation) can be formed by attachment of alkali ions, if alkali-metal salts are present in the sample [58, 59], Cations generally do not need to be added to the sample ubiquitous alkaU-metal impurities are sufficient to give strong alkali-cationized signals. It is reported that for polysaccharides, alkalization occurred much more frequently than protonation. Imaging of MALDI samples shows that the positions of analyte molecules and alkali atoms are highly correlated. In some eases, cationization takes place unfavorably, also in MALDI [46],... 

The improvement in mechanical properties by inorganic fillers is considerably reduced if there is a nonuniform dispersion of particles in the polymer matrix by formation of agglomerates. NMRI can produce visual pictures of the spatial variation of the organic phase distribution. This is accomplished by observing the proton images of the elastomers as a function of proton density and spin-spin, T2, relaxation times. These NMR parameters provide a measure of the molecular mobility, which in turn is related to the spatial variation of the polymer and the filler in the sample. 

---