MRI of Hyperpolarized Protons Against a Large 1H Background

L. BULJUBASICH; JAN F. DECHENT; LAURA M. SCHREIBER; HANS W. SPIESS; KERSTIN MÜNNEMANN

Conferencia; Euromar 2011; 2011

A major challenge in molecular imaging is the detection of tiny amounts of interesting molecules. In magnetic resonance imaging (MRI) their signals are usually concealed by the large background signal of the body. Hyperpolarization can overcome this issue by increasing the nuclear magnetic resonance (NMR) signals few orders of magnitude. For the most widely used NMR and MRI nucleus 1H, however, this strategy is limited. The enormous number of thermally polarized protons in the body screens the small amount of hyperpolarized ones. In this work we present a simple approach dealing with parahydrogenated molecules (i.e., molecules generated in a reaction with Parahydrogen1,2), leading to a 1H NMR/MRI contrast. It makes use of different temporal evolution of the antiphase signal of hyperpolarized 1H generated with PHIP3,4 compared to that of the thermal signal of the background. By choosing an optimal delay time for detection of the PHIP antiphase signals this new contrast can be simply implemented in any MRI pulse sequence.