A MULTIDIMENSIONAL PARTITION ANALYSIS OF SSFP IMAGE PULSE SEQUENCES

The k-space description, of MRI pulse sequences, has been combined wit h a partition model in order to model the image reconstruction and the contrast behaviour found in SSFP pulse sequences, A partition represe nts the magnetisation created, due to excitation by a given rf pulse. In the present model, it is visualised as a set of parameters rather t han a vector sum taken over a collection of spins, A multidimensional parameter space, where each dimension is associated with one of the pa rtition parameters, is introduced in order to describe the interaction between partitions and pulse sequence events (e.g., rf pulses and gra dients). The three k-space dimensions form the first three dimensions and higher orders are used to handle phase dispersions due to diffusio n and main field inhomogeneities. The model makes it possible to perfo rm fast simulation of images resulting from general SSFP pulse sequenc es, A computer implementation generates images (256 matrix), containin g more than 10 different T-1/T-2 combinations, in less than 45 s on a 120 MHz Pentium computer, The contrast behaviour and signal intensitie s found in simulated images show excellent agreement with data generat ed using a clinical MRI scanner system. (C) 1997 Elsevier Science Inc.