Abstract: A T2 preparation sequence uses a segmented BIR-4 adiabatic pulse with two substantially equal delays and is insensitive to B1 field variations and can simultaneously suppress fat signals with low specific absorption rate (SAR). An adiabatic reverse half passage pulse is applied followed by a predetermined delay. An adiabatic full passage pulse is applied followed by a substantially equal delay, followed by an adiabatic half passage pulse. Fat signal suppression is achieved by increasing or decreasing either the first delay or the second delay.

Abstract: A system and method are disclosed to acquire high temporal resolution free-breathing cardiac MR images. The technique includes monitoring heart rate of a patient just prior to image acquisition to acquire a time period of an R—R interval, and using this time period from the heart rate monitoring to prospectively estimate future R—R intervals. The acquisition of MR data can then commence at any point in an R—R interval and extend for the time period recorded. The data acquisition can be segmented and acquired in successive R—R intervals, then combined to create high temporal resolution images.

Abstract: A real-time imaging and visualization method and system that allows multiple field-of-view imaging on multiple receiver channels is disclosed. The method and system implement a semi-bit reversed modified phase-encoding scheme to acquire identical data over all receiver channels, and to reconstruct independently on each channel an image thereby providing multiple FOV images. The method and system provide for real-time catheter tracking where separate receiver channels collect anatomical roadmap data, guidewire data, and catheter data. The present invention uses a loopless antenna to acquire projection images thereby allowing the entire antenna and structures within its diameter of sensitivity to appear as a bright signal and a long narrow connected region. The present invention allows for very narrow FOV imaging for guidewire and catheter channels as well as full FOV imaging for roadmap image reconstruction.

Abstract: A system and method are disclosed to acquire high temporal resolution free-breathing cardiac MR images. The technique includes monitoring heart rate of a patient just prior to image acquisition to acquire a time period of an R-R interval, and using this time period from the heart rate monitoring to prospectively estimate future R-R intervals. The acquisition of MR data can then commence at any point in an R-R interval and extend for the time period recorded. The data acquisition can be segmented and acquired in successive R-R intervals, then combined to create high temporal resolution images.

Abstract: A system and method for creating MR images using mask data that is copied forward for on-the-fly image subtraction for use within such techniques as MR angiography is disclosed. The invention includes acquiring an MR mask image comprised of a plurality of k-space lines, and then copying the k-space line data of the MR mask image into a number of different memory locations. The number of different memory locations corresponds to a preselected number of MR image acquisitions as set by an MR operator. The invention next includes acquiring the preselected number of MR images, each comprised of k-space line data. As the k-space line data is acquired, it is then immediately accumulated in one of the memory locations having the MR mask image k-space line data. By setting a polarity of the data stored, each acquired k-space line of an acquired MR image is subtracted from a corresponding k-space line of the MR mask image in real time. The image is then reconstructed using the subtracted k-space line data.

Abstract: A method is provided for estimating or determining the linear phase shift of an MR signal pertaining to an object of interest. In accordance with the method, an MR sequence is applied to the object, to acquire a set of MR data samples in a specified domain, such as the time domain, the acquired data samples having an associated linear phase shift. A set of conjugate data samples is generated from the acquired data samples, in a domain conjugate to the specified domain such as the frequency domain. The linear phase shift is then determined from the conjugate data samples, by means of computations which are executed exclusively in the conjugate domain. The efficiency of such computations is comparable to the efficiency of the Ahn algorithm. The resultant linear phase shift is employed to reduce artifacts in constructing an MR image of the object, in connection with an MR technique such as navigator echo, or multi-echo imaging.

Abstract: A method is provided for acquiring MR image data, which comprises the steps of applying a succession of RF excitation pulses to a selected region of an imaging subject to produce a corresponding succession of MR data signals, generating a readout gradient in association with each of the MR data signals, and acquiring sets of data points from the MR data signals to provide views respectively corresponding thereto. The data points of a view are respectively identified by positions in k-space along a first k-space axis, each of the positions along the first k-space axis having a time offset with respect to a reference.