A correction technique of the total magnetic field inhomogeneity effects including the localized object induced inhomogeneities such as chemical shift and susceptibility is developed and its usefulness is experimentally demonstrated. With this new and simple technique all the inhomogeneity induced artifacts can be corrected simultaneously. The basic idea of this method is to add a compensation gradient of the same amplitude as the selection gradient in simultaneity with the reading gradient in such a way that the view angle is tilted. Thereby all the inhomogeneity induced geometrical shifts and hence the intensity changes are corrected, since the addition of the compensation which is independent from the field inhomogeneities including both chemical shifts and susceptibility. This technique has been theoretically examined and its usefulness is demonstrated by experiments.

A new angiography technique using the susceptibility effect is proposed. Blood containing deoxyhemoglobin is more paramagnetic than surrounding tissue and thereby produces a susceptibility effect at blood-tissue interfaces. By use of a specially tailored RF pulse, signals from normal tissues are suppressed while the signals from blood interfaces, where strong susceptibility-induced fields are created, are enhanced. The design and characteristic behavior of the tailored RF pulse are discussed and experimental results obtained using both a phantom and a human volunteer with a 2.0-T whole-body NMR system are also presented.

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