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Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

Impulse SequencesA 3.0 T MR system implements all the impulse sequences usually applied in clinical practice such as spin echo (SE): normal, fast 2D and 3D; gradient echo (GE): GRASS / Fast-GRASS 2D and 3D, SPGR / Fast SPGR 2D e 3D; echoplanar (EPI): single shot / multishot 2D e 3D; inversion recovery (IR): STIR, FLAIR (normal, fast), using the usual imaging parameters like flow and respiratory compensation, cardiac and peripheral gating, graphic prescription, fat/water saturation, variable bandwidth and asymmetric field of view.Both the user interface and the parameters of these sequences are the same as those of 1.5 T systems so that recompiling such sequences on 3.0 T systems should theoretically yield exactly the same images with the advantage of high field strength, namely a double signal intensity. In practice, much depends on the relaxation times (T1 and T2) and the SAR 1-3 . As

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