Reducing the radiation dose for CT colonography using adaptive statistical iterative reconstruction: A pilot study

Kristina T. Flicek, Amy K. Hara, Alvin C Silva, Qing Wu, Mary B. Peter, C. Daniel Johnson

Research output: Contribution to journalArticle

164 Citations (Scopus)

Abstract

OBJECTIVE. The purpose of our study was to evaluate the feasibility of preserving image quality during CT colonography (CTC) using a reduced radiation dose with adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHODS. A proven colon phantom was imaged at standard dose settings (50 mAs) and at reduced doses (10-40 mAs) using six different ASIR levels (0-100%). We assessed 2D and 3D image quality and noise to determine the optimal dose and ASIR setting. Eighteen patients were then scanned with a standard CTC dose (50 mAs) in the supine position and at a reduced dose of 25 mAs with 40% ASIR in the prone position. Three radiologists blinded to the scanning techniques assessed 2D and 3D image quality and noise at three different colon locations. A score difference of ≥ 1 was considered clinically important. Actual noise measures were compared between the standard-dose and low-dose acquisitions. RESULTS. The phantom study showed image noise reduction that correlated with a higher percentage of ASIR. In patients, no significant image quality differences were identified between standard- and low-dose images using 40% ASIR. Overall image quality was reduced for both image sets as body mass index increased. Measured image noise was less with the low-dose technique using ASIR. CONCLUSION. The results of this pilot study show that the radiation dose during CTC can be reduced 50% below currently accepted low-dose techniques without significantly affecting image quality when ASIR is used. Further evaluation in a larger patient group is warranted.

Original languageEnglish (US)
Pages (from-to)126-131
Number of pages6
JournalAmerican Journal of Roentgenology
Volume195
Issue number1
DOIs
StatePublished - Jul 2010

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Computed Tomographic Colonography
Radiation
Noise
Colon
Prone Position
Supine Position
Body Mass Index

Keywords

  • Adaptive statistical iterative reconstruction (ASIR)
  • Colonography
  • CT
  • Radiation dose

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

Reducing the radiation dose for CT colonography using adaptive statistical iterative reconstruction : A pilot study. / Flicek, Kristina T.; Hara, Amy K.; Silva, Alvin C; Wu, Qing; Peter, Mary B.; Johnson, C. Daniel.

In: American Journal of Roentgenology, Vol. 195, No. 1, 07.2010, p. 126-131.

Research output: Contribution to journalArticle

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abstract = "OBJECTIVE. The purpose of our study was to evaluate the feasibility of preserving image quality during CT colonography (CTC) using a reduced radiation dose with adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHODS. A proven colon phantom was imaged at standard dose settings (50 mAs) and at reduced doses (10-40 mAs) using six different ASIR levels (0-100{\%}). We assessed 2D and 3D image quality and noise to determine the optimal dose and ASIR setting. Eighteen patients were then scanned with a standard CTC dose (50 mAs) in the supine position and at a reduced dose of 25 mAs with 40{\%} ASIR in the prone position. Three radiologists blinded to the scanning techniques assessed 2D and 3D image quality and noise at three different colon locations. A score difference of ≥ 1 was considered clinically important. Actual noise measures were compared between the standard-dose and low-dose acquisitions. RESULTS. The phantom study showed image noise reduction that correlated with a higher percentage of ASIR. In patients, no significant image quality differences were identified between standard- and low-dose images using 40{\%} ASIR. Overall image quality was reduced for both image sets as body mass index increased. Measured image noise was less with the low-dose technique using ASIR. CONCLUSION. The results of this pilot study show that the radiation dose during CTC can be reduced 50{\%} below currently accepted low-dose techniques without significantly affecting image quality when ASIR is used. Further evaluation in a larger patient group is warranted.",
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