Pulse sequence generated oblique magnetic resonance imaging: Applications to cardiac imaging

Bernstein, Matt A.; Perman, William H.; Besozzi, Myrwood C.; Thomasson, David

doi:10.1118/1.595868

Cited by 15 publications

(6 citation statements)

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“…The gradient control would be one obvious subsystem with which to interface. Images of oblique cuts in present MRI devices are obtained by generating linear combinations of the basic slice select, phase encoding, and frequency encoding gradient waveforms (25). A different combination is sent to each of the x, y, and z gradients.…”

Section: Discussionmentioning

confidence: 99%

MR fluoroscopy: Technical feasibility

Riederer

Tasciyan

Farzaneh

et al. 1988

Magnetic Resonance in Med

370

275

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A method of magnetic resonance image acquisition and reconstruction is described in which high imaging rates and fast reconstruction times are allowed. The acquisition is a modification of the basic FLASH sequence but with a restricted number N of phase encodings. The encodings are applied sequentially, periodically, and continuously. Images are formed by sliding a window of width N encodings along the acquired data and reconstructing an image for each position of the window. In general the acquisition time per image exceeds the time between successive images, and the method thus has a temporal lag. Experimental studies were performed with a dynamic phantom using 48 phase encodings and a TR of 20 ms, for an image acquisition time of about 1 s. The image display rate in the reconstructed sequence was 12.5 images/s, and the image sequence portrayed the motion of the phantom. Additional studies were done with 24 encodings. It is shown how the sliding window technique lends itself to high-speed reconstruction, with each newly acquired echo used to quickly update the image on display. The combination of the acquisition technique described and a hardware implementation of the reconstruction algorithm can result in realtime MR image acquisition and reconstruction.

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Section: Discussionmentioning

confidence: 99%

MR fluoroscopy: Technical feasibility

Riederer

Tasciyan

Farzaneh

et al. 1988

Magnetic Resonance in Med

370

275

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show abstract

“…Consider two right-handed coordinate systems, the physical coordinate system corresponding to the physical x, y, and z gradients of the MRI system and the logical coordi-nate system corresponding to the frequency-encode (xЈ), phase-encode (yЈ), and slice-select (zЈ) directions. The two systems are related by simple rotation (7). Let p ជ 1 , p ជ 2 , and p ជ 3 be the points selected by the user in the physical reference frame.…”

Section: Algorithmmentioning

confidence: 99%

Interactive three-point localization of double-oblique sections using MR fluoroscopy

Debbins¹,

Kruger²,

Fain³

et al. 1999

Magn. Reson. Med.

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Magnetic resonance imaging allows significant freedom in selecting the orientation and position of a tomographic section. However, it can nonetheless be challenging to determine quickly and efficiently the correct parameters required to image a targeted anatomic structure that may lie at an oblique angle in the imaging volume. We describe a three‐point tool in which a) the user interactively selects three points from an anatomic structure of interest during live MR fluoroscopy; b) adjustments to pulse sequence are calculated to image the tomographic section defined by the three points; and c) the section is then immediately imaged fluoroscopically. The tool allows quick localization of, for example, longitudinal images of specific arterial structures. Magn Reson Med 41:846–849, 1999. © 1999 Wiley‐Liss, Inc.

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“…The second plateau duration is a function of the dead-period pulse width. Because the pulse width is known and the ramps are of maximum slew rate, this leads to 2 3 or eight possible design cases that differ only by the sign of the slope of the three ramps that compose the waveform. These cases are illustrated in Fig.…”

Section: Waveform Designmentioning

confidence: 99%

Minimizing dead-periods in flow-encoded or -compensated pulse sequences while imaging in oblique planes

Bolster

Atalar

1999

J. Magn. Reson. Imaging

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A technique is developed to minimize magnetic resonance pulse sequence dead-periods, with first and higher moment requirements, while imaging in oblique planes. Deadperiod requirements of starting amplitude, ending amplitudes, area, and other moment requirements are transformed from the image coordinate system to the physical gradient coordinate system, where the waveforms are then designed. With this technique, the full capabilities of the gradient hardware are utilized. An online algorithm is presented to perform dead-period minimization and gradient waveform design when the first moment and area of the dead-period are specified. The algorithm is then used to implement three-axis flow-compensation in a fast spoiled gradient-echo sequence. This results in a minimal increase in TE and TR over an equivalent non-flow-compensated sequence, and little variation in the minimum TR over the entire range of oblique slice orientations. Applications of this algorithm extend to the optimization of any pulse sequence in which the first moment is important and oblique imaging is required.

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Pulse sequence generated oblique magnetic resonance imaging: Applications to cardiac imaging

Cited by 15 publications

References 0 publications

MR fluoroscopy: Technical feasibility

MR fluoroscopy: Technical feasibility

Interactive three-point localization of double-oblique sections using MR fluoroscopy

Minimizing dead-periods in flow-encoded or -compensated pulse sequences while imaging in oblique planes

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