Gradient strength

For a given half width at half maximum in the time domain, Ar,.n =2, /, the slice width A decreases with increasing gradient strength G. ... 

The aehievable spatial resolution is limited by several eflfeets. The first is the maximum gradient strength and eneoding times available. Bearing in mind equation B1.14.1 and = l/A/n, the pixel size resulting from... 

Figure Bl.14.13. Derivation of the droplet size distribution in a cream layer of a decane/water emulsion from PGSE data. The inset shows the signal attenuation as a fiinction of the gradient strength for diflfiision weighting recorded at each position (top trace = bottom of cream). A Stokes-based velocity model (solid lines) was fitted to the experimental data (solid circles). The curious horizontal trace in the centre of the plot is due to partial volume filling at the water/cream interface. The droplet size distribution of the emulsion was calculated as a fiinction of height from these NMR data. The most intense narrowest distribution occurs at the base of the cream and the curves proceed logically up tlirough the cream in steps of 0.041 cm. It is concluded from these data that the biggest droplets are found at the top and the smallest at the bottom of tlie cream.

The choice of gradient strength and duration can be optimized if the size of the object is known. From Eqs. (1.5 and 1.6) it becomes clear that a large gradient will... 

The gradient strength is G and — G for echo and antiecho selection, respectively. 

Figure 1.50 Basic pulse sequence for PCSE diffusion measurements. C = gradient strength, J = delay between the midpoints of the gradients,...

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