DESIGN OF PRACTICAL T-2-SELECTIVE RF EXCITATION (TELEX) PULSES

Traditional T-2-based imaging techniques are geared toward imaging lon g-T-2 species. Traditional techniques are, therefore, not optimal in c linical situations where the information of interest lies in the short -T-2 species. T-2-selective RF excitation (TELEX) is a technique for o btaining a T-2-based contrast that highlights short-T-2 values while s uppressing long-T-2 values-opposite to traditional T-2 contrast. Previ ously, TELEX has been demonstrated qualitatively to highlight only ver y short-T-2 values (T-2 approximate to 0.001 s). When applied to longe r T-2 values (T-2 greater than or equal to 0.01 s), TELEX becomes sens itive to Delta B-0 non-uniformities. This restricts its application to problems in which the T-2 of interest is very short. In this study, T ELEX is characterized quantitatively. Furthermore, a bandwidth broaden ing scheme is developed that reduces the Delta B-0 sensitivity of TELE X This permits the technique to be applied to longer T-2 values. The c apabilities and limitations of a practical implementation of TELEX are discussed.