Attenuation-based automatic tube voltage selection and tube current modulation for dose reduction at contrast-enhanced liver CT.

PURPOSE To retrospectively determine whether the combined use of automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) can effectively reduce radiation dose at contrast material-enhanced liver computed tomography (CT) while maintaining acceptable image quality compared with the use of ATCM alone. MATERIALS AND METHODS This study was approved by an institutional review board, and informed consent was waived. Three hundred fourteen consecutive patients suspected of having liver disease were divided into three groups. In two groups, both ATVS and ATCM were used (group A1, n=97; group A2, n=101) but with different contrast gain settings; in one group, only ATCM with a fixed tube potential of 120 kV (group B, n=116) was used. Weighted volume CT dose index and dose-length product, contrast-to-noise ratios (CNRs), and mean image noise were assessed. Qualitative analysis was performed by two board-certified radiologists and one radiology resident. Statistical analysis was performed by using the one-way analysis of variance test, two-tailed paired t test, Kruskal-Wallis test, and noninferiority test. RESULTS In groups A1 and A2, a significant dose reduction was obtained compared with that in group B (P<.0001). The mean dose reduction was 20% in group A1 and 31% in group A2. Furthermore, CNRs were significantly higher in groups A1 and A2 than in group B (P<.0001). Despite the higher image noise in groups A1 and A2, the overall image quality was acceptable. CONCLUSION Compared with the use of ATCM alone, the combined use of ATVS and ATCM allowed reduction of radiation exposure while maintaining good image quality at contrast-enhanced liver CT.

[1]  Ehsan Samei,et al.  Hypervascular liver tumors: low tube voltage, high tube current multi-detector row CT for enhanced detection--phantom study. , 2008, Radiology.

[2]  Takeshi Nakaura,et al.  Abdominal CT with low tube voltage: preliminary observations about radiation dose, contrast enhancement, image quality, and noise. , 2005, Radiology.

[3]  D. Sahani,et al.  Cranial CT with Adaptive Statistical Iterative Reconstruction: Improved Image Quality with Concomitant Radiation Dose Reduction , 2012, American Journal of Neuroradiology.

[4]  T. Mulkens,et al.  Use of an automatic exposure control mechanism for dose optimization in multi-detector row CT examinations: clinical evaluation. , 2005, Radiology.

[5]  Thomas Flohr,et al.  Comparison of angular and combined automatic tube current modulation techniques with constant tube current CT of the abdomen and pelvis. , 2006, AJR. American journal of roentgenology.

[6]  Toshinori Hirai,et al.  Comparison of standard- and low-tube voltage MDCT angiography in patients with peripheral arterial disease , 2010, European Radiology.

[7]  C. McCollough,et al.  Optimal tube potential for radiation dose reduction in pediatric CT: principles, clinical implementations, and pitfalls. , 2011, Radiographics : a review publication of the Radiological Society of North America, Inc.

[8]  G Allan Johnson,et al.  Liver: single breath-hold dynamic subtraction CT with multi-detector row helical technology feasibility study. , 2002, Radiology.

[9]  Ashok Panigrahy,et al.  Reducing abdominal CT radiation dose with the adaptive statistical iterative reconstruction technique in children: a feasibility study , 2011, Pediatric Radiology.

[10]  C. McCollough,et al.  CT dose reduction and dose management tools: overview of available options. , 2006, Radiographics : a review publication of the Radiological Society of North America, Inc.

[11]  J. Bruix,et al.  Management of hepatocellular carcinoma: An update , 2011, Hepatology.

[12]  M. Gunn,et al.  State of the art: technologies for computed tomography dose reduction , 2010, Emergency Radiology.

[13]  Y. Yamashita,et al.  Low-kilovoltage, high-tube-current MDCT of liver in thin adults: pilot study evaluating radiation dose, image quality, and display settings. , 2011, AJR. American journal of roentgenology.

[14]  M. Kalra,et al.  Reducing radiation dose in emergency computed tomography with automatic exposure control techniques , 2005, Emergency Radiology.

[15]  Thomas L Toth,et al.  Detection and characterization of lesions on low-radiation-dose abdominal CT images postprocessed with noise reduction filters. , 2004, Radiology.

[16]  E. Samei,et al.  Detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase: effect of a low-tube-voltage, high-tube-current CT technique--preliminary results. , 2010, Radiology.

[17]  Joel G Fletcher,et al.  Automatic selection of tube potential for radiation dose reduction in CT: a general strategy. , 2009, Medical physics.

[18]  Kazuo Awai,et al.  Aortic and hepatic enhancement and tumor-to-liver contrast: analysis of the effect of different concentrations of contrast material at multi-detector row helical CT. , 2002, Radiology.

[19]  K. Shiwaku,et al.  Appropriate BMI for Asian populations , 2004, The Lancet.

[20]  Willi A Kalender,et al.  Application- and patient size-dependent optimization of x-ray spectra for CT. , 2009, Medical physics.

[21]  Screening patients with multi-detector computed axial tomography (MDCT): when will we inform patients about the risk of radiation? , 2008, Emergency Medicine Journal.

[22]  J. Haaga,et al.  Radiation dose management: weighing risk versus benefit. , 2001, AJR. American journal of roentgenology.

[23]  M. Kalra,et al.  Strategies for CT radiation dose optimization. , 2004, Radiology.

[24]  Harlan M Krumholz,et al.  Exposure to low-dose ionizing radiation from medical imaging procedures. , 2009, The New England journal of medicine.

[25]  Naveen M. Kulkarni,et al.  Low-dose MDCT and CT enterography of patients with Crohn disease: feasibility of adaptive statistical iterative reconstruction. , 2011, AJR. American journal of roentgenology.

[26]  E. Samei,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. , 2010, Radiology.

[27]  L. Tanoue.  Computed Tomography — An Increasing Source of Radiation Exposure , 2009 .

[28]  Ehsan Samei,et al.  Hypervascular liver tumors: low tube voltage, high tube current multidetector CT during late hepatic arterial phase for detection--initial clinical experience. , 2009, Radiology.

[29]  Natalie N. Braun,et al.  Strategies for reducing radiation dose in CT. , 2009, Radiologic clinics of North America.

[30]  M. Macari,et al.  Dual Source Dual Energy MDCT: Comparison of 80 kVp and Weighted Average 120 kVp Data for Conspicuity of Hypo-Vascular Liver Metastases , 2010, Investigative radiology.

[31]  Rainer Raupach,et al.  Automated Attenuation-Based Tube Potential Selection for Thoracoabdominal Computed Tomography Angiography: Improved Dose Effectiveness , 2011, Investigative radiology.

[32]  Thomas L Toth,et al.  Dose reduction and compliance with pediatric CT protocols adapted to patient size, clinical indication, and number of prior studies. , 2009, Radiology.

[33]  H. M. Krumholz,et al.  Exposure to Low-Dose Ionizing Radiation from Medical Imaging Procedures , 2009 .

[34]  Bernhard Bischoff,et al.  Image quality and radiation exposure with a low tube voltage protocol for coronary CT angiography results of the PROTECTION II Trial. , 2010, JACC. Cardiovascular imaging.