Undersampled projection reconstruction applied to MR angiography

Peters, Dana C.; Korosec, Frank R.; Grist, Thomas M.; Block, Walter F.; Holden, James E.; Vigen, Karl K.; Mistretta, Charles A.

doi:10.1002/(sici)1522-2594(200001)43:1<91::aid-mrm11>3.0.co;2-4

Cited by 349 publications

(335 citation statements)

References 27 publications

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“…Alternatively, PC-PR can be used to reduce the total scan time without decreasing the spatial and/or temporal resolution. Although azimuthal undersampling does not decrease the spatial resolution, it does introduce streak artifacts (14) that in most cases are tolerable when the number of signalgenerating objects in the field of view (FOV) is limited and the signal-to-noise ratio (SNR) of these objects is high. The intensity of streak artifacts increases with the amount of undersampling (15).…”

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confidence: 99%

Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

Wentland

Korosec

Vigen

et al. 2006

Magnetic Resonance Imaging

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Purpose:To assess the accuracy of flow measurements in vitro and in vivo during scan times shorter than a breathhold using a 2D cine phase contrast (PC) undersampled radial acquisition method, which may be useful for measuring flow, especially in vessels subject to motion during respiration. Materials and Methods:For in vitro assessment, a flow phantom was imaged at various flow rates and undersampling factors. For in vivo assessment, five normal subjects were imaged and the flow rate in the aorta was compared with the sum of the flow rates in the iliac arteries. Results:For results in vitro, the accuracy of flow measurements was maintained with scan times as low as 13-17 seconds. For results in vivo, scans acquired in less than 25 seconds provided flow measurements in the aorta that corresponded well to the sum of flow measurements in the iliac arteries. Conclusion:The undersampled radial acquisition cine PC technique provided accurate flow measurements in a flow phantom and in healthy human volunteers in scan times shorter than a typical breath-hold.

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confidence: 99%

Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

Wentland

Korosec

Vigen

et al. 2006

Magnetic Resonance Imaging

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“…The full flexibility to reconstruct images with different temporal resolutions is achieved by using a constant angular profile spacing, given by the golden ratio, y GR ¼ 111. 25 . This approach guarantees quasiuniform profile distribution for an arbitrary temporal resolution.…”

Section: Data Acquisition Schemementioning

confidence: 99%

“…In traditional radial frequency encoding trajectories (25), undersampling in the radial direction would not make sense. In contrast, the proposed trajectory allows the flexibility of undersampling both the angular and radial directions of the PE plane.…”

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3D undersampled golden‐radial phase encoding for DCE‐MRA using inherently regularized iterative SENSE

Prieto

Uribe

Razavi

et al. 2010

Magnetic Resonance in Med

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One of the current limitations of dynamic contrast-enhanced MR angiography is the requirement of both high spatial and high temporal resolution. Several undersampling techniques have been proposed to overcome this problem. However, in most of these methods the tradeoff between spatial and temporal resolution is constant for all the time frames and needs to be specified prior to data collection. This is not optimal for dynamic contrast-enhanced MR angiography where the dynamics of the process are difficult to predict and the image quality requirements are changing during the bolus passage. Here, we propose a new highly undersampled approach that allows the retrospective adaptation of the spatial and temporal resolution. The method combines a three-dimensional radial phase encoding trajectory with the golden angle profile order and non-Cartesian Sensitivity Encoding (SENSE) reconstruction. Different regularization images, obtained from the same acquired data, are used to stabilize the non-Cartesian SENSE reconstruction for the different phases of the bolus passage. The feasibility of the proposed method was demonstrated on a numerical phantom and in three-dimensional intracranial dynamic contrast-enhanced MR angiography of healthy volunteers. The acquired data were reconstructed retrospectively with temporal resolutions from 1.2 sec to 8.1 sec, providing a good depiction of small vessels, as well as distinction of different temporal phases. Magn Reson Med 64:514-526, 2010. V C 2010 Wiley-Liss, Inc.Key words: DCE-MRA; undersampling; golden-radial phase encoding; SENSE; regularization.The simultaneous high spatial and temporal resolution required in dynamic MRI is limited due to time acquisition constraints. This is especially important in applications such as dynamic contrast-enhanced MR angiography (DCE-MRA), where for example high spatial resolution is required to visualize small vasculature structures, whereas high temporal resolution is needed to achieve adequate distinction between arterial and venous vessels (1). To attain this goal, several undersampling acquisition and reconstruction techniques have been proposed. These techniques speed up the acquisition of dynamic MRI by reducing the number of acquired samples in k-t space. The missing data can be estimated by exploiting the high spatial-temporal correlation of dynamic process (2-9), by using prior information (10,11), or by employing spatial sensitivity encoding in parallel imaging acquisitions (12)(13)(14).For most of those techniques, the tradeoff between spatial and temporal resolutions is constant for all the time frames and must be specified prior to data acquisition. However, in DCE-MRA a time-varying retrospective adaptation of this tradeoff would be of great benefit. For instance, a high temporal resolution is desirable to visualize the arrival of the contrast agent to the vessels of interest, though a lower spatial resolution is bearable for this part of the dynamic process. Conversely, for arterial and venous signal peak phases, a high spatial ...

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“…Angularly undersampled PR, in which the number of projections is less than ( /2)N r , has been applied to MR angiography (3)(4)(5), myocardial wall tagging (1), MR fluoroscopy (6,7), and cardiac cine imaging (8 -10). Acquisition has been performed in both two and three (11) dimensions.…”

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confidence: 99%

“…Acquisition has been performed in both two and three (11) dimensions. Undersampled PR images are accompanied by undersampling artifacts, which have been reported to be tolerable in some applications (3).…”

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confidence: 99%

A modified projection reconstruction trajectory for reduction of undersampling artifacts

Wang

Grimm

Riederer

2005

Magnetic Resonance Imaging

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Purpose: To reduce undersampling artifacts for a given number of repetitions of the projection reconstruction (PR) sequence by modifying its k-space trajectory to sample more mid-frequencies while reducing the sampling coverage of the peripheral spatial frequencies. Materials and Methods:The single k-space spoke measured per repetition in the standard PR was modified so that one complete and two partial spokes were measured per repetition but with decreased k-space extent. The point spread functions (PSFs) and undersampling artifacts of the modified PR were compared with those of the standard PR for various numbers of projections. Phantom and in vivo images were used to assess the relative performance.Results: PSF analysis indicated that the modified PR method provided reduced undersampling artifacts with somewhat reduced spatial resolution. The phantom and in vivo images corroborated this. Conclusion:The modified PR trajectory provides reduced undersampling artifact vs. the standard PR, particularly when the number of projections is limited and the artifact level is high.

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Undersampled projection reconstruction applied to MR angiography

Cited by 349 publications

References 27 publications

Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

3D undersampled golden‐radial phase encoding for DCE‐MRA using inherently regularized iterative SENSE

A modified projection reconstruction trajectory for reduction of undersampling artifacts

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