Phase versus amplitude sorting of 4D‐CT data

Wink, Nicole M; Panknin, Christoph; Solberg, T.D.

doi:10.1120/jacmp.v7i1.2198

Cited by 83 publications

(30 citation statements)

References 23 publications

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“…In the present work, the Advantage4D software uses phase to group series images. A recent study reported some improvement if amplitude is used instead of phase (28) . We define “phase tolerance” (percent) as the width of the phase interval used to reconstruct a series at a given phase.…”

Section: Methodsmentioning

confidence: 99%

Initial evaluation of a four‐dimensional computed tomography system, using a programmable motor

Simon

Giraud

Servois

et al. 2006

J Applied Clin Med Phys

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A dynamic lung tumor phantom was used to investigate the geometric reconstruction accuracy of a commercial four‐dimensional computed tomography (4D‐CT) system. A ball filled with resin, embedded in a cork cube, was placed on a moving platform. Various realistic antero‐posterior (AP) motions were programmed to reproduce the respiratory motion of a lung tumor. Several three‐dimensional (3D) CT and 4D‐CT images of this moving object were acquired and compared using different acquisition parameters. Apparent volume and diameter of the ball were measured and compared to the real values. The position of two points (the AP limits of the ball) during the motion in the coordinate system of the CT scanner were also compared with the expected values. Volume error was shown to increase with object speed. However, although the volume error was associated with intraslice artifacts, it did not reflect large interslice inconstancies in object position and should not be used as an indicator of image accuracy. The 3D‐CT gave a random position of the tumor along the phantom excursion; accuracy in the assessment of position by 4D‐CT ranged from 0.4 mm to 2.6 mm during extreme phases of breathing. We used average projection (AVE) and maximum intensity projection (MIP) algorithms available on the commercial software to create internal target volumes (ITVs) by merging gross tumor volume (GTV) images at various respiratory phases. The ITVs were compared to a theoretical value computed from the programmed ball excursion. The ITVs created from the MIP algorithm were closer to the theoretical value (within 12%) than were those created from the AVE algorithm (within 40%).PACS numbers: 87.53.Xd, 87.56.Mp, 87.57.Ce, 87.59.Fm

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Section: Methodsmentioning

confidence: 99%

Initial evaluation of a four‐dimensional computed tomography system, using a programmable motor

Simon

Giraud

Servois

et al. 2006

J Applied Clin Med Phys

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“…In general, two main binning strategies are used: phase binning and amplitude binning [9, 13–15]. For phase binning, peaks in the respiratory signal are detected and the respiratory cycle is divided in equidistant time bins (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…One of the challenges of 4DMRI (and 4DCT) is that irregular breathing is known to deteriorate image quality and introduce image artifacts [9–15]. Various strategies of handling irregular breathing have been demonstrated for 4DMRI: e.g., discarding of images associated with an amplitude that falls outside a defined range of amplitudes or applying triggering in order to only obtain images within a certain respiratory amplitude range [11, 16, 17].…”

Section: Introductionmentioning

confidence: 99%

A novel amplitude binning strategy to handle irregular breathing during 4DMRI acquisition: improved imaging for radiotherapy purposes

et al. 2019

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Background For radiotherapy of abdominal cancer, four-dimensional magnetic resonance imaging (4DMRI) is desirable for tumor definition and the assessment of tumor and organ motion. However, irregular breathing gives rise to image artifacts. We developed a outlier rejection strategy resulting in a 4DMRI with reduced image artifacts in the presence of irregular breathing. Methods We obtained 2D T2-weighted single-shot turbo spin echo images, with an interleaved 1D navigator acquisition to obtain the respiratory signal during free breathing imaging in 2 patients and 12 healthy volunteers. Prior to binning, upper and lower inclusion thresholds were chosen such that 95% of the acquired images were included, while minimizing the distance between the thresholds (inclusion range (IR)). We compared our strategy (Min95) with three commonly applied strategies: phase binning with all images included (Phase), amplitude binning with all images included (MaxIE), and amplitude binning with the thresholds set as the mean end-inhale and mean end-exhale diaphragm positions (MeanIE). We compared 4DMRI quality based on: Data included (DI); percentage of images remaining after outlier rejection. Reconstruction completeness (RC); percentage of bin-slice combinations containing at least one image after binning. Intra-bin variation (IBV); interquartile range of the diaphragm position within the bin-slice combination, averaged over three central slices and ten respiratory bins. IR. Image smoothness (S); quantified by fitting a parabola to the diaphragm profile in a sagittal plane of the reconstructed 4DMRI. A two-sided Wilcoxon’s signed-rank test was used to test for significance in differences between the Min95 strategy and the Phase, MaxIE, and MeanIE strategies. Results Based on the fourteen subjects, the Min95 binning strategy outperformed the other strategies with a mean RC of 95.5%, mean IBV of 1.6 mm, mean IR of 15.1 mm and a mean S of 0.90. The Phase strategy showed a poor mean IBV of 6.2 mm and the MaxIE strategy showed a poor mean RC of 85.6%, resulting in image artifacts (mean S of 0.76). The MeanIE strategy demonstrated a mean DI of 85.6%. Conclusions Our Min95 reconstruction strategy resulted in a 4DMRI with less artifacts and more precise diaphragm position reconstruction compared to the other strategies. Trial registration Volunteers: protocol W15_373#16.007; patients: protocol NL47713.018.14 Electronic supplementary material The online version of this article (10.1186/s13014-019-1279-z) contains supplementary material, which is available to authorized users.

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“…We chose an amplitude-based phase assignment method because of the greater accuracy of amplitudebased gated treatment over phase-based gating in clinical situations (30,31).…”

Section: Treatment Planningmentioning

confidence: 99%

Comparison of Respiratory-Gated and Respiratory-Ungated Planning in Scattered Carbon Ion Beam Treatment of the Pancreas Using Four-Dimensional Computed Tomography

Mori¹,

Yanagi²,

Hara³

et al. 2010

International Journal of Radiation Oncology*Biology*Physics

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Phase versus amplitude sorting of 4D‐CT data

Cited by 83 publications

References 23 publications

Initial evaluation of a four‐dimensional computed tomography system, using a programmable motor

Initial evaluation of a four‐dimensional computed tomography system, using a programmable motor

A novel amplitude binning strategy to handle irregular breathing during 4DMRI acquisition: improved imaging for radiotherapy purposes

Comparison of Respiratory-Gated and Respiratory-Ungated Planning in Scattered Carbon Ion Beam Treatment of the Pancreas Using Four-Dimensional Computed Tomography

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