PERFIDI: parametrically enabled relaxation filters with double and multiple inversion.
We present a novel approach to the nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) analysis of complex samples with nontrivial distribution of longitudinal relaxation rate R(1). Parametrically enabled relaxation filters with double and multiple inversion (PERFIDI) aim to separate signals arising from components with different R(1) values prior to actual data acquisition. Given any standard NMR/MRI pulse sequence, which, by itself, is insensitive to differences in R(1) values, it can be combined with a PERFIDI preamble, which functions as a preliminary R(1) filter and confers on the original technique sensitivity to the dimension R(1). This article states the principles of the approach, including the way to account for instrumental imperfections, and shows how PERFIDI with specific filter profile functions can be built. Using terms borrowed from electronics, these filters are classified as low-pass, high-pass and band-pass types. Also included are an experimental verification example and a discussion of potential applications of PERFIDI in various NMR areas.
Sykora
Stanislav
S
Extra Byte, Via Raffaello Sanzio 22C, Castano Primo I-20022, Italy.
Bortollotti
Villiam
V
Fantazzini
Paola
P
D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012815:Signal Processing, Computer-Assisted