Figure 1

The field-focusing effect is illustrated in a phantom image. Relative signal intensity profiles (ξ) are shown as a function of position (x) in a CuSO₄ bottle. On the left is a signal intensity profile for a 90° flip angle in a 1.5T scanner. Signal intensity is fairly uniform across the bottle. On the right is a signal intensity profile for a 90° flip angle in a 3.0T scanner. Signal intensity is focused at the center of the bottle.