Abstract: The present invention provides the use of a persistent .pi.-system free radical for the manufacture of a contrast medium for use in magnetic resonance imaging, wherein the electron delocalising .pi.-system of said radical comprises at least one homo or heterocyclic ring, said radical being other than the chloranil semiquinone anion radical or a trityl radical. Also provided are magnetic resonance imaging contrast media containing and methods using such radicals.

Abstract: The present invention relates to a method of generating a magnetic resonance image of a sample comprising introducing into the sample a physiologically tolerable deuterated stable free radical, exposing the sample to first and second radiations of frequencies selected respectively to excite nuclear spin transitions in selected nuclei in the sample and to excite electron spin resonance transitions of the free radical coupled to nuclear spin transitions of at least some of the nuclei, detecting free induction decay signals from the sample, and generating a magnetic resonance image from these signals.

Abstract: The invention relates to a modification of electron spin resonance enhanced magnetic resonance imaging (ESREMRI) in which two magnetically responsive materials (contrast agents) are introduced into the sample being investigated, one contrast agent serving as an ESREMRI free induction decay signal enhancing agent and the other as enhancement suppressing agent. In this way, image contrast may be enhanced further for regions in which the suppressing agent distributes poorly or not at all or which the suppressing agent reaches at a later time than the enhancing agent.

Abstract: There is provided an improved magnetic resonance imaging procedure which essentially combines electron spin resonance enhanced MRI with echo planar imaging MRI.

Abstract: There is provided a method of and apparatus for thermographic imaging involving the use in electron spin resonance enhanced magnetic resonance imaging (ESREMRI) of a paramagnetic contrast agent having in its esr spectrum a temperature dependant transition. The ESREMRI enhancement of the free induction decay signal resultant on stimulating that transition with radiation of a set frequency or frequency band is itself accordingly temperature dependant.

Abstract: The present invention describes a method of and apparatus for performing electron spin resonance enhanced magnetic resonance imaging (ESREMRI) at ultra-low fields of up to 20 Gauss, optionally dispensing with a primary magnet and using the earth's ambient field to provide the primary magnetic field for the magnetic resonance imaging procedure.

Abstract: A method of generating a magnetic resonance image of a sample comprising introducing into the sample a contrast medium comprising a paramagnetic material having an electron spin resonance transition having a linewidth of 1 Gauss or less; exposing the sample to a first radiation of a frequency selected to excite nuclear spin transitions in selective nuclei in the sample and exposing the sample to a second radiation of a frequency which excites electron spin transitions coupled to nuclear spin transitions of at least some nuclei, the second radiation being of a frequency selected to excite an electron spin resonance transition of the paramagnetic material; detecting free induction decay signals from the sample; and generating therefrom a magnetic resonance image of the sample.