title: PERFIDI filters to suppress and/or quantify relaxation time components in multi-component systems: an example for fat-water systems.
abstract: Parametrically Enabled Relaxation FIlters with Double and multiple Inversion (PERFIDI) is an experimental NMR/MRI technique devised to analyze samples/voxels characterized by multi-exponential longitudinal relaxation. It is based on a linear combination of NMR sequences with suitable preambles composed of inversion pulses. Given any standard NMR/MRI sequence, it permits one to modify it in a way which will attenuate, in a predictable manner and before data acquisition, signals arising from components with different r rates (r=1/T1). Consequently, it is possible to define relatively simple protocols to suppress and/or to quantify signals of different components. This article describes a simple way to construct low-pass, high-pass and band-pass PERFIDI filters. Experimental data are presented in which the method has been used to separate fat and water proton signals. We also present a novel protocol for very fast determination of the ratio between the fat signal and the total signal which avoids any time-consuming magnetization recovery multi-array data acquisition. The method has been validated also for MRI, producing well T1-contrasted images.
authors.affiliation: Department DICAM, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Bortolotti
authors.forename: P
authors.initials: P
authors.lastname: Fantazzini
authors.forename: M
authors.initials: M
authors.lastname: Gombia
authors.forename: D
authors.initials: D
authors.lastname: Greco
authors.forename: G
authors.initials: G
authors.lastname: Rinaldin
authors.forename: S
authors.initials: S
authors.lastname: Sykora
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000465:Algorithms; D000818:Animals; D002417:Cattle; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D018482:Muscle, Skeletal / Q000737:chemistry*; D012815:Signal Processing, Computer-Assisted; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water