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Attenuation-based automatic kilovoltage selection and sinogram-affirmed iterative reconstruction: effects on radiation exposure and image quality of portal-phase liver CT.

Song JS, Choi EJ, Kim EY, Kwak HS, Han YM - Korean J Radiol (2015)

Bottom Line: Reconstructed images were then qualitatively and quantitatively compared with protocol A images.Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.

ABSTRACT

Objective: To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver.

Materials and methods: We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images.

Results: Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).

Conclusion: Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

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Related in: MedlinePlus

Transverse contrast-enhanced liver CT images of 67-year-old female (body mass index, 26.7 kg/m2) with liver cirrhosis.Previous CT (A) was scanned at 120 kV (136 eff. mAs) with volume CT dose index (CTDIvol) of 10.4 mGy and follow-up CT (B) was performed at 100 kV (132 eff. mAs) with CTDIvol of 5.2 mGy. Both readers selected (B) as preferred image.
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Figure 2: Transverse contrast-enhanced liver CT images of 67-year-old female (body mass index, 26.7 kg/m2) with liver cirrhosis.Previous CT (A) was scanned at 120 kV (136 eff. mAs) with volume CT dose index (CTDIvol) of 10.4 mGy and follow-up CT (B) was performed at 100 kV (132 eff. mAs) with CTDIvol of 5.2 mGy. Both readers selected (B) as preferred image.

Mentions: Objective image noise was lower in protocol B compared to protocol A, without statistical significance. There was no significant difference in the mean CT attenuation of liver and paraspinal muscles. The mean CT attenuation of the portal vein was significantly higher with protocol B (216.2 ± 40.8 vs. 233.1 ± 44.2, p = 0.005). There were no significant differences in SNRliver, SNRportal vein, and CNRportal vein (Table 2). Qualitative analysis results were shown in Table 3. Interobserver agreement was moderate to almost perfect. The radiologist with 20-year of clinical experience preferred both images in 53.7% (36/67), protocol A in 28.4% (19/67), and protocol B in 17.9% (12/67). The radiologist with 6-year clinical experience preferred both images in 59.7% (40/67), protocol A in 10.4% (7/67), protocol B in 29% (20/67) (p < 0.001) (Fig. 2).


Attenuation-based automatic kilovoltage selection and sinogram-affirmed iterative reconstruction: effects on radiation exposure and image quality of portal-phase liver CT.

Song JS, Choi EJ, Kim EY, Kwak HS, Han YM - Korean J Radiol (2015)

Transverse contrast-enhanced liver CT images of 67-year-old female (body mass index, 26.7 kg/m2) with liver cirrhosis.Previous CT (A) was scanned at 120 kV (136 eff. mAs) with volume CT dose index (CTDIvol) of 10.4 mGy and follow-up CT (B) was performed at 100 kV (132 eff. mAs) with CTDIvol of 5.2 mGy. Both readers selected (B) as preferred image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296279&req=5

Figure 2: Transverse contrast-enhanced liver CT images of 67-year-old female (body mass index, 26.7 kg/m2) with liver cirrhosis.Previous CT (A) was scanned at 120 kV (136 eff. mAs) with volume CT dose index (CTDIvol) of 10.4 mGy and follow-up CT (B) was performed at 100 kV (132 eff. mAs) with CTDIvol of 5.2 mGy. Both readers selected (B) as preferred image.
Mentions: Objective image noise was lower in protocol B compared to protocol A, without statistical significance. There was no significant difference in the mean CT attenuation of liver and paraspinal muscles. The mean CT attenuation of the portal vein was significantly higher with protocol B (216.2 ± 40.8 vs. 233.1 ± 44.2, p = 0.005). There were no significant differences in SNRliver, SNRportal vein, and CNRportal vein (Table 2). Qualitative analysis results were shown in Table 3. Interobserver agreement was moderate to almost perfect. The radiologist with 20-year of clinical experience preferred both images in 53.7% (36/67), protocol A in 28.4% (19/67), and protocol B in 17.9% (12/67). The radiologist with 6-year clinical experience preferred both images in 59.7% (40/67), protocol A in 10.4% (7/67), protocol B in 29% (20/67) (p < 0.001) (Fig. 2).

Bottom Line: Reconstructed images were then qualitatively and quantitatively compared with protocol A images.Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.

ABSTRACT

Objective: To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver.

Materials and methods: We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images.

Results: Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).

Conclusion: Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

Show MeSH
Related in: MedlinePlus