Carotid dual-energy CT angiography: evaluation of low keV calculated monoenergetic datasets by means of a frequency-split approach for noise reduction at low keV levels
Background and purpose - Calculated monoenergetic ultra-low keV datasets did not lead to improved contrast-to-noise ratio (CNR) due to the dramatic increase in image noise. The aim of the present study was to evaluate the objective image quality of ultra-low keV monoenergetic images (MEIs) calculate...
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| Main Authors: | , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
April 2016
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| In: |
European journal of radiology
Year: 2016, Volume: 85, Issue: 4, Pages: 720-725 |
| ISSN: | 1872-7727 |
| DOI: | 10.1016/j.ejrad.2016.01.015 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1016/j.ejrad.2016.01.015 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S0720048X16300158 
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| Author Notes: | Philipp Riffel, Holger Haubenreisser, Mathias Meyer, Sonja Sudarski, John N. Morelli, Bernhard Schmidt, Stefan O. Schoenberg, Thomas Henzler |
| Summary: | Background and purpose - Calculated monoenergetic ultra-low keV datasets did not lead to improved contrast-to-noise ratio (CNR) due to the dramatic increase in image noise. The aim of the present study was to evaluate the objective image quality of ultra-low keV monoenergetic images (MEIs) calculated from carotid DECT angiography data with a new monoenergetic imaging algorithm using a frequency-split technique. - Materials and methods - 20 patients (12 male; mean age 53±17 years) were retrospectively analyzed. MEIs from 40 to 120keV were reconstructed using the monoenergetic split frequency approach (MFSA). Additionally MEIs were reconstructed for 40 and 50keV using a conventional monoenergetic (CM) software application. Signal intensity, noise, signal-to-noise ratio (SNR) and CNR were assessed in the basilar, common, internal carotid arteries. - Results - Ultra-low keV MEIs at 40keV and 50keV demonstrated highest vessel attenuation, significantly greater than those of the polyenergetic images (PEI) (all p-values <0.05). The highest SNR level and CNR level was found at 40keV and 50keV (all p-values <0.05). MEIs with MFSA showed significantly lower noise levels than those processed with CM (all p-values <0.05) and no significant differences in vessel attenuation (p>0.05). Thus MEIs with MFSA showed significantly higher SNR and CNR compared to MEIs with CM. - Conclusion - Combining the lower spatial frequency stack for contrast at low keV levels with the high spatial frequency stack for noise at high keV levels (frequency-split technique) leads to improved image quality of ultra-low keV monoenergetic DECT datasets when compared to previous monoenergetic reconstruction techniques without the frequency-split technique. |
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| Item Description: | Gesehen am 18.04.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1872-7727 |
| DOI: | 10.1016/j.ejrad.2016.01.015 |