Extended field‐of‐view imaging with table translation and frequency sweeping

Zhu, Yangying; Dumoulin, Charles L.

doi:10.1002/mrm.10470

Cited by 30 publications

(37 citation statements)

References 10 publications

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“…Three-dimensional CMT imaging (5,11,12) was chosen for MR scout image acquisition because it is efficient in terms of signal-to-noise ratio (SNR). Sufficient SNR facilitates isotropic spatial resolution, which is advantageous for all kinds of image processing applications, and allows use of the system's body coil for MR signal reception, to simplify the approach even further.…”

Section: Concept and Implementationmentioning

confidence: 99%

Towards automatic patient positioning and scan planning using continuously moving table MR imaging

Koken

Dries

Keupp

et al. 2009

Magnetic Resonance in Med

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A concept is proposed to simplify patient positioning and scan planning to improve ease of use and workflow in MR. After patient preparation in front of the scanner the operator selects the anatomy of interest by a single push-button action. Subsequently, the patient table is moved automatically into the scanner, while real-time 3D isotropic low-resolution continuously moving table scout scanning is performed using patient-independent MR system settings. With a real-time organ identification process running in parallel and steering the scanner, the target anatomy can be positioned fully automatically in the scanner's sensitive volume. The desired diagnostic examination of the anatomy of interest can be planned and continued immediately using the geometric information derived from the acquired 3D data. The concept was implemented and successfully tested in vivo in 12 healthy volunteers, focusing on the liver as the target anatomy. The positioning accuracy achieved was on the order of several millimeters, which turned out to be sufficient for initial planning purposes. Furthermore, the impact of nonoptimal system settings on the positioning performance, the signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) was investigated. The present work proved the basic concept of the proposed approach as an element of future scan automation. Magn

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Section: Concept and Implementationmentioning

confidence: 99%

Towards automatic patient positioning and scan planning using continuously moving table MR imaging

Koken

Dries

Keupp

et al. 2009

Magnetic Resonance in Med

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“…From the basic concepts available (7)(8)(9)(10)(11)(12)(13), the lateral readout method was chosen, which is described in detail in Ref. 13.…”

Section: Continuously Moving Table Signal Samplingmentioning

confidence: 99%

“…This approach entails frequent acceleration and deceleration of the patient table, which is not optimal with respect to sampling efficiency and patient comfort. Therefore, MR data acquisition during continuous table motion (7)(8)(9)(10)(11)(12)(13) has received significant interest recently, although it makes scanning technically more challenging.…”

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confidence: 99%

Whole‐body 3D water/fat resolved continuously moving table imaging

Börnert

Keupp

Eggers

et al. 2007

Magnetic Resonance Imaging

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Purpose:To study the feasibility of three-dimensional (3D) whole-body, head-to-toe, water/fat resolved MRI, using continuously moving table imaging technology. Materials and Methods:Experiments were performed on nine healthy volunteers, acquiring 3D whole-body head-totoe data under continuous motion of the patient table. Two different approaches for water/fat separation have been studied. Results of a three-point chemical shift encoding and a spectral presaturation technique were compared with respect to image quality and performance. Furthermore, fast, low-resolution, whole-body water/fat imaging was performed in two minutes total scan time to derive patient-specific parameters such as the total water/fat ratio, the intraperitoneal/extraperitoneal fat ratio, and the body mass index (BMI). Results:Good water/fat separation with decent image quality was obtained in all cases. The three-point chemical shift encoding approach was found to be more efficient with respect to signal-to-noise ratio (SNR) and acquisition time. Conclusion:Whole-body water/fat sensitive MRI using continuous table motion is feasible and could be of interest for clinical practice. Some improvements of the method are desirable.

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“…The technique is analogous to the receiver-frequency sweeping used in Ref. 11. The patient's extent in the A/P direction is covered by N y (primary) phase encodings.…”

Section: Theorymentioning

confidence: 99%

Continuously moving table 3D MRI with lateral frequency‐encoding direction

Aldefeld¹,

Börnert²,

Keupp³

2006

Magnetic Resonance in Med

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A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective ( For MRI of extended regions of the human body, such as in angiography and cancer screening, the patient table must be moved because the useful field of view (FOV) is limited in clinical scanners. The established method for this purpose is to acquire the MR data at a number of successive stations while the table is at rest (1,2). Alternatively, the MR data are acquired continuously while the table moves, which is technically more demanding but can offer shorter scan time and increased flexibility in the imaging of dynamic processes. Continuously moving table methods can be subdivided into two main approaches: In the first one, data are acquired from transverse (axial) slices positioned at or near the isocenter (3-7). This approach benefits from the good field homogeneity obtainable in transverse slices, but is not optimal from an SNR standpoint, since data are acquired from only a small slice volume. In the second approach, which is addressed in this paper, data are acquired simultaneously from a large 3D volume. Several scanning strategies are possible here, with different tradeoffs among SNR, speed of acquisition, and image quality.Dietrich and Hajnal (8) proposed a continuously moving table method based on 3D Cartesian k-space scanning in which the frequency-encoding (readout) direction is chosen along a transverse direction, the secondary phaseencoding along the direction of motion. To compensate for the table motion, each acquired full set of secondary phase-encoding data is Fourier transformed along the direction of motion and shifted to its corresponding anatomical location in hybrid space (mixed Fourier/spatial domain). A slab-selective RF pulse is applied to avoid signal aliasing along the head-feet direction. Kruger et al. (9) described a method in which the frequency-encoding direction is chosen parallel with the direction of motion, which obviates the need for slab selection. Gradient nonlinearity correction has been incorporated into this scheme (10), allowing larger 3D acquisition volumes. Zhu and D...

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Extended field‐of‐view imaging with table translation and frequency sweeping

Abstract: A new method for MRI of an extended field of view (FOV) has been developed and validated. The method employs concurrent MR data acquisition and patient table motion.

Cited by 30 publications

References 10 publications

Towards automatic patient positioning and scan planning using continuously moving table MR imaging

Towards automatic patient positioning and scan planning using continuously moving table MR imaging

Whole‐body 3D water/fat resolved continuously moving table imaging

Continuously moving table 3D MRI with lateral frequency‐encoding direction

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