Journal article
Reducing CT radiation dose with iterative reconstruction algorithms: the influence of scan and reconstruction parameters on image quality and CTDIvol.
- Klink T Inselspital - Bern University Hospital, University Institute of Diagnostic, Interventional, and Pediatric Radiology, Freiburgstrasse 10, 3010 Bern, Switzerland; University of Würzburg, Insitute of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany. Electronic address: klink_t1@ukw.de.
- Obmann V Inselspital - Bern University Hospital, University Institute of Diagnostic, Interventional, and Pediatric Radiology, Freiburgstrasse 10, 3010 Bern, Switzerland. Electronic address: verena.obmann@insel.ch.
- Heverhagen J Inselspital - Bern University Hospital, University Institute of Diagnostic, Interventional, and Pediatric Radiology, Freiburgstrasse 10, 3010 Bern, Switzerland. Electronic address: johannes.heverhagen@insel.ch.
- Stork A Roentgeninstitut Duesseldorf, Kaiserswerterstrasse 89, 40476 Duesseldorf, Germany. Electronic address: a.stork@roentgeninstitut.de.
- Adam G University Medical Center Hamburg Eppendorf, Department of Diagnostic and Interventional Radiology, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address: g.adam@uke.de.
- Begemann P Roentgeninstitut Duesseldorf, Kaiserswerterstrasse 89, 40476 Duesseldorf, Germany. Electronic address: p.begemann@roentgeninstitut.de.
- 2014-07-20
Published in:
- European journal of radiology. - 2014
Computed tomography
Hybrid iterative reconstruction
Image quality
Phantom
Radiation dose
Algorithms
Image Processing, Computer-Assisted
Observer Variation
Phantoms, Imaging
Radiation Dosage
Radiographic Image Interpretation, Computer-Assisted
Signal-To-Noise Ratio
Tomography, X-Ray Computed
English
OBJECTIVES
In this phantom CT study, we investigated whether images reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) with reduced tube voltage and current have equivalent quality. We evaluated the effects of different acquisition and reconstruction parameter settings on image quality and radiation doses. Additionally, patient CT studies were evaluated to confirm our phantom results.
METHODS
Helical and axial 256 multi-slice computed tomography scans of the phantom (Catphan(®)) were performed with varying tube voltages (80-140kV) and currents (30-200mAs). 198 phantom data sets were reconstructed applying FBP and IR with increasing iterations, and soft and sharp kernels. Further, 25 chest and abdomen CT scans, performed with high and low exposure per patient, were reconstructed with IR and FBP. Two independent observers evaluated image quality and radiation doses of both phantom and patient scans.
RESULTS
In phantom scans, noise reduction was significantly improved using IR with increasing iterations, independent from tissue, scan-mode, tube-voltage, current, and kernel. IR did not affect high-contrast resolution. Low-contrast resolution was also not negatively affected, but improved in scans with doses <5mGy, although object detectability generally decreased with the lowering of exposure. At comparable image quality levels, CTDIvol was reduced by 26-50% using IR. In patients, applying IR vs. FBP resulted in good to excellent image quality, while tube voltage and current settings could be significantly decreased.
CONCLUSIONS
Our phantom experiments demonstrate that image quality levels of FBP reconstructions can also be achieved at lower tube voltages and tube currents when applying IR. Our findings could be confirmed in patients revealing the potential of IR to significantly reduce CT radiation doses.
In this phantom CT study, we investigated whether images reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) with reduced tube voltage and current have equivalent quality. We evaluated the effects of different acquisition and reconstruction parameter settings on image quality and radiation doses. Additionally, patient CT studies were evaluated to confirm our phantom results.
METHODS
Helical and axial 256 multi-slice computed tomography scans of the phantom (Catphan(®)) were performed with varying tube voltages (80-140kV) and currents (30-200mAs). 198 phantom data sets were reconstructed applying FBP and IR with increasing iterations, and soft and sharp kernels. Further, 25 chest and abdomen CT scans, performed with high and low exposure per patient, were reconstructed with IR and FBP. Two independent observers evaluated image quality and radiation doses of both phantom and patient scans.
RESULTS
In phantom scans, noise reduction was significantly improved using IR with increasing iterations, independent from tissue, scan-mode, tube-voltage, current, and kernel. IR did not affect high-contrast resolution. Low-contrast resolution was also not negatively affected, but improved in scans with doses <5mGy, although object detectability generally decreased with the lowering of exposure. At comparable image quality levels, CTDIvol was reduced by 26-50% using IR. In patients, applying IR vs. FBP resulted in good to excellent image quality, while tube voltage and current settings could be significantly decreased.
CONCLUSIONS
Our phantom experiments demonstrate that image quality levels of FBP reconstructions can also be achieved at lower tube voltages and tube currents when applying IR. Our findings could be confirmed in patients revealing the potential of IR to significantly reduce CT radiation doses.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.1016/j.ejrad.2014.05.033
- PMID 25037931
- Persistent URL
- https://sonar.ch/global/documents/131944
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