Imaging parameters

The combination of microscopic and macroscopic information is made possible by what can be called parameter imaging . In the general sense, it consists of the encoding of properties such as spectral line shifts, relaxation times, diffusion coefficients, etc., in the image by suitable combination of corresponding modules into one pulse sequence. Parameter images are to be distinguished from mere... 

S. Stapf, X. Ren, E. Talnishnikh, B. Bliimich 2005, (Spatial distribution of coke residues in porous catalyst pellets analyzed by field-cycling relaxometry and parameter imaging), Magn. Reson. Imag. 23, 383. 

Parameter images are of interest in so far, as NMR parameters can be correlated with material properties either by experimental calibration or by theoretical models. An example for experimental parameter calibration is given in Figure 7.6 with a quantitative... 

Figure 7.6 NMR parameter image of a strained poly(dimethylsiloxane) rubber band with a cut and calibration curves (a) Experimental curve for T2 versus strain, (b) Experimental stress-strain relationship, (c) Calibration curve for T2 versus strain obtained from combination of curves a and b, (d) Stress image obtained by recalibration of a T2 parameter image. The stress contours range from 0 to 2.4 MPa...

Figure 7.19 Time-resolved T2 parameter images across a 1.4 mm thick sheet of SBR...

Figure 7.21 Temperature profiles from T2 parameter images of SBR cylinders with different carbon-black filler contents undergoing oscillatory shear deformation (a) Temperature calibration curves, (b) Temperature profiles across the cylinders...

Latent cirrhosis There are no subjective complaints or clinical symptoms. This stage is identified by laboratory parameters, imaging procedures or histological examination of the liver. Frequency is between 10 and 20%. 

Fig. 7,1,6 [Fii l ] Photo (a) and 7 parameter image (b) of a 23 mm x 31 mm section of a laminated glass window pane illustrating the different contrast features of visible light and the T2...

Depending on the particular pulse sequence used and on the coherence order, the multi-quantum build-up curves can be calculated in the short-time regime for a particular chemical group [Schl2]. From these known expressions, parameter images of... 

The different information obtainable from a chemical-shift weight and a relaxation-parameter image is illusiraled in Fig. 8.3,2 Pra3] In covulcanization of different rubber sheets, for example, sheets from SBR and NR, an interface may arise depending on the materials and the conditions of vulcanization (Fig. 8.3.2(a)). A sufficiently long acquisition delay t without chemical-shift refocusing introduces the chemical-shift... 

Fig. 9.2.8 Tz parameter imaging with a surface coil, (a) The phantom consists of three sheets from poly(urethane) rubber. A magnetic-field gradient was applied perpendicular to the surface coil for space encoding along the depth axis y. (b) A two-pulse sequence with flip angles a and 2a, respectively, was used for excitation, (c) Stack of ID images for different echo times fg = 2r. (d) 7) parameter image extracted from the signal decays in c.

Here Tz enters as the limit of Tip for vanishing lock-field strength Buy. Therefore, given a Ti parameter image and a map of B y R), the correlation time Xc of molecular motion can be mapped in the weak collision limit. 

Relaxation and spin-diffiision parameter imaging of strained polymers... 

Because H linewidths in many elastomers are of the order of 3 kHz or less, spin-echo and gradient-echo imaging techniques can be applied. Contrast is introduced by suitable filters like Ti and double-quantum filters or by use of the spectroscopic dimension. Parameter images of T2, the double-quantum signal intensity, or the quadrupolar coupling strength are evaluated and rescaled according to theory or experimental calibration data (cf. Section 7.1.6). 

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