Algorithms for extracting motion information from navigator echoes

Wang, Yi; Grimm, Roger C.; Felmlee, Joel P.; Riederer, Stephen J.; Ehman, Richard L.

doi:10.1002/mrm.1910360120

Cited by 77 publications

(68 citation statements)

References 15 publications

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“…21 Alternatively, the use of automated algorithms for the detection of the period of minimal myocardial motion has been suggested. [22][23][24] The subsequent scans can then be tailored for data acquisition to occur only during this predefined quiescent period (Fig. 4).…”

Section: A Triggering On the Electrocardiogrammentioning

confidence: 99%

Motion Compensation Strategies in Magnetic Resonance Imaging

Heeswijk

Bonanno

Coppo

et al. 2012

Crit Rev Biomed Eng

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Image quality in magnetic resonance imaging (MRI) is considerably affected by motion. Therefore, motion is one of the most common sources of artifacts in contemporary cardiovascular MRI. Such artifacts in turn may easily lead to misinterpretations in the images and a subsequent loss in diagnostic quality. Hence, there is considerable research interest in strategies that help to overcome these limitations at minimal cost in time, spatial resolution, temporal resolution, and signal-to-noise ratio. This review summarizes and discusses the three principal sources of motion: the beating heart, the breathing lungs, and bulk patient movement. This is followed by a comprehensive overview of commonly used compensation strategies for these different types of motion. Finally, a summary and an outlook are provided.

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Section: A Triggering On the Electrocardiogrammentioning

confidence: 99%

Motion Compensation Strategies in Magnetic Resonance Imaging

Heeswijk

Bonanno

Coppo

et al. 2012

Crit Rev Biomed Eng

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show abstract

“…Onedimensional navigator profiles were acquired before each dynamic repetition of the imaging sequence by performing a readout along the axis of the excited pencil beam. The imaging slice position was adaptively corrected in real-time based on the estimated target displacement as obtained via correlation analysis of subsequently acquired navigator profiles (15,28). The duration of the single nonselective 2D RF pulse was 6.1 ms, whereas the duration of the fat-selective 2D RF pulse train was 19.9 ms.…”

Section: Mr Imagingmentioning

confidence: 99%

“…A 1-2-1 binomial waterselective RF pulse was used to suppress the signal of the fat and avoid thermometry errors. The imaging slice position was adaptively corrected in real-time by modifying the excitation frequency of the water-selective RF pulse according to the estimated kidney motion obtained via correlation analysis of the navigator profiles (15,28).…”

Section: Mr Thermometrymentioning

confidence: 99%

Spectrally selective pencil‐beam navigator for motion compensation of MR‐guided high‐intensity focused ultrasound therapy of abdominal organs

Köhler

Senneville

Quesson

et al. 2011

Magnetic Resonance in Med

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MR-guided high-intensity focused ultrasound (MR-HIFU) is a noninvasive technique for depositing thermal energy in a controlled manner deep within the body. However, the MR-HIFU treatment of mobile abdominal organs is problematic as motion-related thermometry artifacts need to be corrected and the focal point position must be updated in order to follow the moving organ to avoid damaging healthy tissue. In this article, a fat-selective pencil-beam navigator is proposed for real-time monitoring and compensation of through-plane motion. As opposed to the conventional spectrally nonselective navigator, the fat-selective navigator does not perturb the water-proton magnetization used for proton resonance frequency shift thermometry. This allows the proposed navigator to be placed directly on the target organ for improved motion estimation accuracy. The spectral and spatial selectivity of the proposed navigator pulse is evaluated through simulations and experiments, and the improved slice tracking performance is demonstrated in vivo by tracking experiments on a human kidney and on a human liver. The direct motion estimation provided by the fat-selective navigator is also shown to enable accurate motion compensated MR-HIFU therapy of in vivo porcine kidney, including motion compensation of thermometry and beam steering based on the observed threedimensional kidney motion. Magn Reson Med 66:102-111,

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“…For each navigator echo, the absolute displacement Y was determined relative to a prestored navigator profile obtained in an initial dummy cycle phase. The displacement was calculated in real-time using a least-squares algorithm (15). This information was used in the MAG real-time gating routine to calculate which phase encoding step should be measured next.…”

Section: Methodsmentioning

confidence: 99%