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A METHOD FOR CALCULATING OPTIMUM SLEW RATE FOR GRADIENTS IN MAGNETIC RESONANCE IMAGING

IP.com Disclosure Number: IPCOM000033823D
Publication Date: 2004-Dec-29

Publishing Venue

The IP.com Prior Art Database

Abstract

In an embodiment, a method for calculating optimum slew rate for gradients in MRI includes starting with maximum value of the slew rate. If the Reilly fraction for the slew rate violates the limit, then a new slew rate is predicted. The new slew rate is determined using the current pulse waveform and the algorithm for calculating dB/dT. Iteration is carried out with different slew rates, changing the timing of the current waveform accordingly. The calculated pseudo waveform is then used as the input to the same algorithm, which is used to calculate the Reilly fraction. The slew rate, which gives the best value of the Reilly fraction, is used as the new slew rate. For the new pulse waveform Reilly fraction is calculated. If there is a violation, the new slew rate is set as the upper limit of slew rate, otherwise, the new slew rate is set it as the lower limit. If the difference between the upper limit and lower limit is within the tolerance limit, the new slew rate is set as the final slew rate, otherwise a new slew rate is predicted. If the new slew rate is not within the upper limit and lower limit, quadratic interpolation is used to calculate the new slew rate.