Brain in vivo MRS without and with water suppression: Padé-based nonderivative, derivative, shape and parameter estimations

The theme of the present study is in vivo brain magnetic resonance spectroscopy for a healthy adult volunteer. The time signals encoded without and with water suppression are analyzed by the nonderivative and derivative fast Padé transform, FPT and dFPT, respectively. Both processors are applied as shape and parameter estimators. The ever existing border between shape and parameter estimators is erased by the nonparametric dFPT. This processor begins as a shape estimator and finishes as a (quantification-equipped) parameter estimator. It forces the given total shape spectrum (envelope) to collapse onto its proper components. Component lineshape reconstructions amount to quantification since isolated peaks in spectra can be parametrized by numerical integrations. The comparably good spectra are obtained for time signals without and with water suppression. Water-unsuppressed encodings beneficially offer faster scanning sequences, eliminate magnetization transfer effects, shorten repetition times and lower the radio-frequency power deposition to the patient.