Abstract: A magnetic resonance imaging system and method for detecting blood flow abnormalities according to the time delay for the arrival of a bolus of a MR contrast agent into localized regions as observed in a temporal series magnetic resonance signals or images obtained subsequent to bolus injection. A rapid series of imaging pulse sequences acquires the time development of the signal from localized regions within the imaged field of view of a body. During the imaging period, a bolus of a MR contrast agent is injected into the cardiovascular system of the body. As the MR contrast material circulates through the imaged region, the associated field gradient which extends into the surrounding tissue results in signal losses in the acquired signal from these regions. The arrival time for the bolus into a given localized region is determined from the acquired time data, and the relative arrival time among regions in the imaged field of view indicates whether there is decreased blood flow to certain areas.

Abstract: A nuclear magnetic resonance pulse sequence to provide spectral encoding so that the resulting series of spin-echoes each include both spatial and spectral information for spectroscopic imaging. Atoms within the object are excited and may then be spatially encoded, as by a phase encoding gradient. A series of refocusing pulses is then applied, inducing a respective series of spin-echoes. Spectral information is directly encoded in the spin-echo signals. The multiple spin-echoes may be used for sampling different points of k-space, and/or for increasing the signal-to-noise ratio by averaging. In an alternative embodiment, the present invention produces compound weighted spectroscopic images by selecting the period between refocussing pulses according to the coupling constant of a group contained in the compound; thereby, the signal of the selected compounds modulate with a known frequency different for compounds with different coupling constants.

Abstract: A method for enhancing the sensitivity of gradient-recalled echo imaging for T2* effects in dynamic magnetic resonance imaging which involves the step of delaying gradient-recalled echoes so that the gradient-recalled echoes are subjected to magnetic susceptibility effects for an extended period of time. The gradient-recalled echoes are delayed beyond a subsequent radio frequency pulse by applying an additional gradient which dephases any gradient-recalled echo of spins that are excited in the radio frequency repetition time period in which said gradient-recalled echoes are produced.

Abstract: A method of obtaining an attenuation curve, and corresponding diffusion constant, from a single-shot procedure. In contrast to the conventional pulsed field-gradient spin echo (PGSE) procedures used to determine the diffusion attenuation curve of a body undergoing magnetic resonance imaging, the method uses a single-shot procedure. The procedure uses application of a single shot pulse sequence to initiate a spin-echo procedure. This procedure creates a number of gradient recalled echoes by alternating the diffusion gradient. Each subsequent gradient-recalled echo is attenuated by an additional pair of gradient pulses. This successive attenuation by the gradient pulses allows the diffusional attenuation curve to be determined accurately in a single procedure. Ratios of time symmetric echo pulses yield a value proportional to the diffusion constant.

Abstract: A method for enhancing the sensitivity of gradient-recalled echo imaging for T2* effects in dynamic magnetic resonance imaging which involves the step of delaying gradient-recalled echoes so that the gradient-recalled echoes are subjected to magnetic susceptibility effects for an extended period of time. The gradient-recalled echoes are delayed beyond a subsequent radio frequency pulse by applying an additional gradient which dephases any gradient-recalled echo of spins that are excited in the radio frequency repetition time period in which said gradient-recalled echoes are produced.