Abstract: The invention relates to a system and method for magnetic resonance imaging. In order to achieve high resolution imaging a magnetic resonance imaging system and method is proposed, wherein magnetic resonance signals using a first resonance frequency are used for a central portion of k-space and magnetic resonance signals using a second resonance frequency are used for a peripheral portion of k-space. In a preferred embodiment of the invention non-proton magnetic resonance signals are used for the central portion of the k-space and proton magnetic resonance signals are used for the periphery of k-space. Accordingly, the reconstructed magnetic resonance image shows contrast relating to the non-proton nuclei and fine resolution dominated by the protons. Hence, the invention can especially provide a solution for the limited time available for the acquisition of non-proton magnetic resonance signals.

Abstract: The invention relates to a method for in vivo measurement of a periodically varying fluid flow in an object by means of magnetic resonance. The method includes a step for applying first and second additional magnetic field gradients in order to shift the phase of a reference magnetization, which phase shift relates to a net flow of the fluid during an interval between the application of the additional magnetic field gradients. According to the invention, near a phase of a period of the periodically varying fluid flow an excitation RF pulse is generated, the first additional gradient is applied and a first additional RF pulse is generated and near a corresponding phase of a second period of the periodically varying fluid flow a second additional RF pulse is generated and the second additional gradient is applied.

Abstract: The invention relates to a method of imaging perfusion parameters of, for example blood in a volume of the brain in the head of a body by means of magnetic resonance, in which a contrast medium is introduced into a blood flow within the body, said contrast medium flowing, via the carotid arteries, to the volume in the head to be imaged by means of magnetic resonance. The images of the volume which are reconstructed from the magnetic resonance signals received are subsequently deconvoluted with an arterial input function of the contrast medium in a supply to the volume imaged. This arterial input function is determined according to the invention by excitation of spins and measurement of a magnetic resonance signal in an elongate part of the body which contains the carotid arteries and has a cross-section which is at least equal to a diameter of a carotid artery.

Abstract: The invention relates to a magnetic resonance imaging method. The method includes the execution of image pulse sequences for the measurement of magnetic resonance image signals and navigator signals. After the execution of the image pulse sequence, the navigator MR signal is checked so as to determine whether the navigator MR signal meets a predetermined quality criterion. If the navigator MR signal does not meet the quality criterion, the navigator MR signal and the magnetic resonance imaging signals corresponding to the navigator MR signal are measured again.

Abstract: The invention relates to a method for imaging diffusion parameters of a body by means of magnetic resonance. The method involves an adjustment pulse sequence and an imaging pulse sequence. The adjustment pulse sequence measures preparation MR signals. The imaging pulse sequence measures position-dependent MR signals. The imaging pulse sequence is adjusted on the basis of information from the preparation MR signals measured during the adjustment pulse sequence.

Abstract: A diffusion weighted MR method for forming images of diffusion of spins in biological tissue. In order to correct macroscopic motions, the MR method measures navigator MR signals wherefrom a phase correction is derived for the MR signals. During the imaging of, for example a part of the brain of a human or animal, artefacts may arise at the areas of the image which correspond to regions in the part of the brain which contain CSF. The artefacts in the MR image can be reduced by determining a corrected phase, for measuring points having a modulus smaller than the threshold value, from the phases of different reference measuring points of the navigator MR signal for which the phase can be determined with a sufficiently small error.

Abstract: The invention relates to a fast imaging method based on gradient recalled echoes of nuclear spins whose excitation and echo formation are not contained in the same sequence. The method has an increased susceptibility to variations in the time constant T.sub.2.sup.* of the free induction decay of the MR signal and is used in, for example, functional MR imaging studies that are based on temporary changes in T.sub.2.sup.* which are caused by local changes in magnetic susceptibility e.g. local changes in brain oxygenation state of a human or animal body. In order to reduce the susceptibility of the image quality to motion navigator gradients are generated in each sequence so as to measure a navigator MR signal. From the measured navigator signals a phase correction is determined and the MR signals measured are corrected by means of this phase correction.