Dataset Information

Gradual edge enhancement in spiral phase contrast imaging with fractional vortex filters.

ABSTRACT: In the spiral phase contrast imaging, the integer spiral phase plate (SPP) are generally employed to perform the radial Hilbert transform on the object. Here we introduce fractional SPP filters, instead of the integer ones, to investigate the gradual formation of edge enhancement for pure phase objects. Two spatial light modulators are used in our experimental configuration. One is addressed to display the pure phase object of a five-pointed star, while the other serves as a dynamic filter of fractional topological charge Q. Of interest is the observation of the complete reversal of the edge and background brightness by gradually changing the fractional vortices from Q = 0 to 1. The experimental results were well interpreted based on the OAM spectra of fractional SPP, which indicates that the filtered output image can be considered as a coherent superposition of all possible images that are individually resulted from the integer OAM filtering. Besides, we show that the spiral phase contrast effect can still be observed in real time for a rotating three-leaf clover. Our results may find potential applications in the optical microscopic imaging.

SUBMITTER: Wang J

PROVIDER: S-EPMC4625183 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Gradual edge enhancement in spiral phase contrast imaging with fractional vortex filters.

Wang Jikang J Zhang Wuhong W Qi Qianqian Q Zheng Shasha S Chen Lixiang L

Scientific reports 20151029

In the spiral phase contrast imaging, the integer spiral phase plate (SPP) are generally employed to perform the radial Hilbert transform on the object. Here we introduce fractional SPP filters, instead of the integer ones, to investigate the gradual formation of edge enhancement for pure phase objects. Two spatial light modulators are used in our experimental configuration. One is addressed to display the pure phase object of a five-pointed star, while the other serves as a dynamic filter of fr ...[more]

PMID: 26510668

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Project description:To validate a prospectively triggered spiral phase-contrast magnetic resonance (MR) sequence accelerated with sensitivity encoding (SENSE) in a population of children and adults with congenital heart disease.The local research ethics committee approved this study, and written consent was obtained from all patients or guardians. Stroke volumes were quantified in 40 patients (mean age ± standard deviation: 21.4 years ± 13.8, age range: 3.0-61.3 years; 22 male patients aged 3.0-38.0 years [mean age, 17.2 years ± 10.5], 18 female patients aged 4.7-61.3 years [mean age, 26.6 years ± 15.9]) with congenital heart disease in the aorta (n = 40), main pulmonary artery (n = 38), right pulmonary artery (n = 22), and left pulmonary artery (n = 24). Stroke volumes were obtained with (a) breath-hold spiral phase-contrast MR imaging with SENSE, (b) conventional breath-hold cartesian phase-contrast MR imaging, and (c) reference free-breathing phase-contrast MR imaging. Stroke volumes were compared by using repeated-measures analysis of variance, Bland-Altman analysis, and correlation coefficients.Imaging time with the breath-hold spiral phase-contrast MR sequence was significantly lower than that with the conventional breath-hold phase-contrast MR sequence (~5 seconds vs ~16 seconds, respectively; P < .0001). There was excellent agreement in stroke volumes in all vessels between the reference free-breathing sequence (mean volume, 60.3 mL ± 27.3) and the two breath-hold sequences-spiral SENSE phase-contrast MR imaging (mean volume, 59.5 mL ± 27.1; P < .001) and conventional cartesian phase-contrast MR imaging (mean volume, 59.8 mL ± 27.6; P = .268). The limits of agreement were smaller with the spiral breath-hold sequence than with the conventional breath-hold sequence (-4.4 mL, 2.9 mL vs -10.3 mL, 9.3 mL, respectively); correlation was similar (r = 0.998 vs r = 0.984, respectively).Flow volumes can be accurately and reliably quantified by using a spiral SENSE phase-contrast MR sequence, with high spatiotemporal resolution obtained in a short breath hold.

Dataset Information

Gradual edge enhancement in spiral phase contrast imaging with fractional vortex filters.

Publications

Gradual edge enhancement in spiral phase contrast imaging with fractional vortex filters.

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