Abstract: The magnetic resonance image of a specimen is encoded by the phase angle response of the volume elements in a slice or volume illuminated by a pulsed radio frequency source, instead of encoded by the magnitude response. The specimen can be imaged before and during intrinsic perturbations such as caused by external stimuli or execution of cognitive or motor tasks. Preferably the specimen is perfused with a paramagnetic contrast agent such as Gadolinium or Dysprosium, slowly or by bolus injection, after recording one or more baseline images. The phase angle response of the specimen can then be recorded one or more times as perturbation subsists or as the bolus traverses the area of illumination. Fast Fourier transformation converts gradient spin echo response data to phase angles for a spatial distribution of volume elements in the illuminated slice.

Abstract: A method of vector magnetic resonance measuring and imaging and associated apparatus provide for a specimen being placed in a main magnetic field, RF pulses being impinged thereon, and magnetic field gradients being superimposed thereupon, preferably with three input gradient pulses being impinged preferably simultaneously to construct a balanced system of four gradient vectors having equally strong moments Four cycles of such input gradient pulses are employed to create four magnetic gradient moments from which velocity or motion vectors are created. A receiver obtains signals from a specimen and converts them into information which is introduced into a computer. The computer converts the signals sensitized by the gradient vector moments into motional-type vector information which can be measured and imaged. Different approaches may be taken for low velocity and high velocity usages.

Abstract: A method of inversion spin echo magnetic resonance imaging includes providing a specimen positioned within a main magnetic field, a source of RF signals, a receiver for receiving signals emitted from the specimen responsive to the RF pulses and emitting responsive output signals, a computer for receiving the output signals from the receiver and establishing image information related thereto and a visual display for displaying images obtained from the image information. During an initial echo period, imposing three pulses on the main magnetic field with the first and third pulses having a first value and the second pulse having a second value which may be approximately double the first value, creating an echo with the second pulse and the third pulse converting this echo into negative longitudinal magnetization.

Abstract: Red blood cells (RBC's) loaded with nonradioactive chromium in paramagnetic form are employed as a contrast agent for magnetic resonance imaging (MRI). The method has promise for intravascular imaging applications where the contrast agent must remain in the circulatory system. Specific uses of this kind include locating gastrointestinal bleeding, differentiation of tumor from edema, MRI angiography, and determination of tissue perfusion. The Cr-labelled RBC's can also be used for liver and/or spleen MRI examinations.