Korean J Radiol.  2015 Oct;16(5):1047-1055. 10.3348/kjr.2015.16.5.1047.

Feasibility Study of Radiation Dose Reduction in Adult Female Pelvic CT Scan with Low Tube-Voltage and Adaptive Statistical Iterative Reconstruction

• Wang X
• He W
• Chen J
• Hu Z
• Zhao L

• KMID: 2160772
• DOI: http://doi.org/10.3348/kjr.2015.16.5.1047

Abstract

OBJECTIVE
To evaluate image quality of female pelvic computed tomography (CT) scans reconstructed with the adaptive statistical iterative reconstruction (ASIR) technique combined with low tube-voltage and to explore the feasibility of its clinical application.
MATERIALS AND METHODS
Ninety-four patients were divided into two groups. The study group used 100 kVp, and images were reconstructed with 30%, 50%, 70%, and 90% ASIR. The control group used 120 kVp, and images were reconstructed with 30% ASIR. The noise index was 15 for the study group and 11 for the control group. The CT values and noise levels of different tissues were measured. The contrast to noise ratio (CNR) was calculated. A subjective evaluation was carried out by two experienced radiologists. The CT dose index volume (CTDIvol) was recorded.
RESULTS
A 44.7% reduction in CTDIvol was observed in the study group (8.18 +/- 3.58 mGy) compared with that in the control group (14.78 +/- 6.15 mGy). No significant differences were observed in the tissue noise levels and CNR values between the 70% ASIR group and the control group (p = 0.068-1.000). The subjective scores indicated that visibility of small structures, diagnostic confidence, and the overall image quality score in the 70% ASIR group was the best, and were similar to those in the control group (1.87 vs. 1.79, 1.26 vs. 1.28, and 4.53 vs. 4.57; p = 0.122-0.585). No significant difference in diagnostic accuracy was detected between the study group and the control group (42/47 vs. 43/47, p = 1.000).
CONCLUSION
Low tube-voltage combined with automatic tube current modulation and 70% ASIR allowed the low CT radiation dose to be reduced by 44.7% without losing image quality on female pelvic scan.

Keyword

Adaptive statistical iterative reconstruction; Tube-voltage; CT; Radiation dose

MeSH Terms

Adult
Aged
Body Mass Index
Feasibility Studies
Female
Genital Diseases, Female/diagnosis/*radiography
Humans
Middle Aged
Pelvis/*radiography
Radiation Dosage
Radiographic Image Interpretation, Computer-Assisted
Signal-To-Noise Ratio
*Tomography, X-Ray Computed

Figure

• 

  Fig. 1 Images reconstructed with different proportions of ASIR and kVp. A-E are reconstructed images using 30% ASIR (100 kVp), 50% ASIR (100 kVp), 70% ASIR (100 kVp), 90% ASIR (100 kVp), and 30% ASIR (120 kVp), respectively. Image scores for these five sets of images were > 3 points. Noise level in D was lower than that in A. Noise level in E was similar to those in C and D. A-D were from same patient with BMI of 23.2 kg/m2 and CTDIvol of 6.35 mGy. E was from another patient with BMI of 22.8 kg/m2 and CTDIvol of 13.3 mGy. ASIR = adaptive statistical iterative reconstruction, BMI = body mass index, CTDIvol = computed tomography dose index volume

• 

  Fig. 2 Locations of ROIs in different tissues. A. Image shows locations of ROI in bladder. B. Image shows locations of ROIs in iliac and fat. C. Image shows locations of ROI in uterine. D. Image shows locations of ROI in obturator muscles. ROI = region of interest

• 

  Fig. 3 Noise level at different ASIR proportions and over smooth appearance on 70% and 90% ASIR images. A-D are 30-90% ASIR images from same patient. Noise level decreased in proportion to increases in ASIR. C and D show over smooth appearance. ASIR = adaptive statistical iterative reconstruction

• 

  Fig. 4 Noise level at different ASIR proportions; over smooth appearance on 90% ASIR image. A-D are 30-90% ASIR images from same patient. Noise level decreased in proportion to increases in ASIR. D shows over smooth appearance. ASIR = adaptive statistical iterative reconstruction

Reference

1. Chen JH, Jin EH, He W, Zhao LQ. Combining automatic tube current modulation with adaptive statistical iterative reconstruction for low-dose chest CT screening. PLoS One. 2014; 9:e92414.

2. Shin HJ, Chung YE, Lee YH, Choi JY, Park MS, Kim MJ, et al. Radiation dose reduction via sinogram affirmed iterative reconstruction and automatic tube voltage modulation (CARE kV) in abdominal CT. Korean J Radiol. 2013; 14:886–893.

3. Pickhardt PJ, Lubner MG, Kim DH, Tang J, Ruma JA, del Rio AM, et al. Abdominal CT with model-based iterative reconstruction (MBIR): initial results of a prospective trial comparing ultralow-dose with standard-dose imaging. AJR Am J Roentgenol. 2012; 199:1266–1274.

4. McCollough CH, Primak AN, Braun N, Kofler J, Yu L, Christner J. Strategies for reducing radiation dose in CT. Radiol Clin North Am. 2009; 47:27–40.

5. Kalra MK, Maher MM, Toth TL, Hamberg LM, Blake MA, Shepard JA, et al. Strategies for CT radiation dose optimization. Radiology. 2004; 230:619–628.

6. Marin D, Nelson RC, Schindera ST, Richard S, Youngblood RS, Yoshizumi TT, et al. Low-tube-voltage, high-tube-current multidetector abdominal CT: improved image quality and decreased radiation dose with adaptive statistical iterative reconstruction algorithm--initial clinical experience. Radiology. 2010; 254:145–153.

7. Yu MH, Lee JM, Yoon JH, Baek JH, Han JK, Choi BI, et al. Low tube voltage intermediate tube current liver MDCT: sinogram-affirmed iterative reconstruction algorithm for detection of hypervascular hepatocellular carcinoma. AJR Am J Roentgenol. 2013; 201:23–32.

8. Hara AK, Paden RG, Silva AC, Kujak JL, Lawder HJ, Pavlicek W. Iterative reconstruction technique for reducing body radiation dose at CT: feasibility study. AJR Am J Roentgenol. 2009; 193:764–771.

9. Martinsen AC, Sæther HK, Hol PK, Olsen DR, Skaane P. Iterative reconstruction reduces abdominal CT dose. Eur J Radiol. 2012; 81:1483–1487.

10. Prakash P, Kalra MK, Digumarthy SR, Hsieh J, Pien H, Singh S, et al. Radiation dose reduction with chest computed tomography using adaptive statistical iterative reconstruction technique: initial experience. J Comput Assist Tomogr. 2010; 34:40–45.

11. Prakash P, Kalra MK, Kambadakone AK, Pien H, Hsieh J, Blake MA, et al. Reducing abdominal CT radiation dose with adaptive statistical iterative reconstruction technique. Invest Radiol. 2010; 45:202–210.

12. Silva AC, Lawder HJ, Hara A, Kujak J, Pavlicek W. Innovations in CT dose reduction strategy: application of the adaptive statistical iterative reconstruction algorithm. AJR Am J Roentgenol. 2010; 194:191–199.

13. Singh S, Kalra MK, Gilman MD, Hsieh J, Pien HH, Digumarthy SR, et al. Adaptive statistical iterative reconstruction technique for radiation dose reduction in chest CT: a pilot study. Radiology. 2011; 259:565–573.

14. Lin XZ, Machida H, Tanaka I, Fukui R, Ueno E, Chen KM, et al. CT of the pancreas: comparison of image quality and pancreatic duct depiction among model-based iterative, adaptive statistical iterative, and filtered back projection reconstruction techniques. Abdom Imaging. 2014; 39:497–505.

15. Sagara Y, Hara AK, Pavlicek W, Silva AC, Paden RG, Wu Q. Abdominal CT: comparison of low-dose CT with adaptive statistical iterative reconstruction and routine-dose CT with filtered back projection in 53 patients. AJR Am J Roentgenol. 2010; 195:713–719.

16. Kalra MK, Prasad S, Saini S, Blake MA, Varghese J, Halpern EF, et al. Clinical comparison of standard-dose and 50% reduced-dose abdominal CT: effect on image quality. AJR Am J Roentgenol. 2002; 179:1101–1106.

17. Singh S, Kalra MK, Moore MA, Shailam R, Liu B, Toth TL, et al. Dose reduction and compliance with pediatric CT protocols adapted to patient size, clinical indication, and number of prior studies. Radiology. 2009; 252:200–208.

18. EUR 16262. European guidelines on quality criteria for computed tomography. http://www.drs.dk/guidelines/ct/quality/download/eur16262.w51.

19. Kondo H, Kanematsu M, Goshima S, Tomita Y, Kim MJ, Moriyama N, et al. Body size indexes for optimizing iodine dose for aortic and hepatic enhancement at multidetector CT: comparison of total body weight, lean body weight, and blood volume. Radiology. 2010; 254:163–169.

20. Schindera ST, Diedrichsen L, Müller HC, Rusch O, Marin D, Schmidt B, et al. Iterative reconstruction algorithm for abdominal multidetector CT at different tube voltages: assessment of diagnostic accuracy, image quality, and radiation dose in a phantom study. Radiology. 2011; 260:454–462.

21. Gervaise A, Osemont B, Louis M, Lecocq S, Teixeira P, Blum A. Standard dose versus low-dose abdominal and pelvic CT: comparison between filtered back projection versus adaptive iterative dose reduction 3D. Diagn Interv Imaging. 2014; 95:47–53.

22. Kaza RK, Platt JF, Al-Hawary MM, Wasnik A, Liu PS, Pandya A. CT enterography at 80 kVp with adaptive statistical iterative reconstruction versus at 120 kVp with standard reconstruction: image quality, diagnostic adequacy, and dose reduction. AJR Am J Roentgenol. 2012; 198:1084–1092.

23. Vardhanabhuti V, Riordan RD, Mitchell GR, Hyde C, Roobottom CA. Image comparative assessment using iterative reconstructions: clinical comparison of low-dose abdominal/pelvic computed tomography between adaptive statistical, model-based iterative reconstructions and traditional filtered back projection in 65 patients. Invest Radiol. 2014; 49:209–216.

24. Singh S, Kalra MK, Hsieh J, Licato PE, Do S, Pien HH, et al. Abdominal CT: comparison of adaptive statistical iterative and filtered back projection reconstruction techniques. Radiology. 2010; 257:373–383.

25. Flicek KT, Hara AK, Silva AC, Wu Q, Peter MB, Johnson CD. Reducing the radiation dose for CT colonography using adaptive statistical iterative reconstruction: a pilot study. AJR Am J Roentgenol. 2010; 195:126–131.

26. Thibault JB, Sauer KD, Bouman CA, Hsieh J. A three-dimensional statistical approach to improved image quality for multislice helical CT. Med Phys. 2007; 34:4526–4544.

27. Xu J, Mahesh M, Tsui BM. Is iterative reconstruction ready for MDCT? J Am Coll Radiol. 2009; 6:274–276.

28. Tang K, Wang L, Li R, Lin J, Zheng X, Cao G. Effect of low tube voltage on image quality, radiation dose, and low-contrast detectability at abdominal multidetector CT: phantom study. J Biomed Biotechnol. 2012; 2012:130169.