Pediatric MDCT: towards assessing the diagnostic influence of dose reduction on the detection of small lung nodules.

RATIONALE AND OBJECTIVES The purpose of this study was to evaluate the effect of reduced tube current (dose) on lung nodule detection in pediatric multidetector array computed tomography (MDCT). MATERIALS AND METHODS The study included normal clinical chest MDCT images of 13 patients (aged 1-7 years) scanned at tube currents of 70 to 180 mA. Calibrated noise addition software was used to simulate cases as they would have been acquired at 70 mA (the lowest original tube current), 35 mA (50% reduction), and 17.5 mA (75% reduction). Using a validated nodule simulation technique, small lung nodules of 3 to 5 mm in diameter were inserted into the cases, which were then randomized and rated independently by three experienced pediatric radiologists for nodule presence on a continuous scale ranging from zero (definitely absent) to 100 (definitely present). The observer data were analyzed to assess the influence of dose on detection accuracy using the Dorfman-Berbaum-Mets method for multiobserver, multitreatment receiver-operating characteristic (ROC) analysis and the Williams trend test. RESULTS The areas under the ROC curves were 0.95, 0.91, and 0.92 at 70, 35, and 17.5 mA, respectively, with standard errors of 0.02 and interobserver variability of 0.02. The Dorfman-Berbaum-Mets method and the Williams trend test yielded P values for the effect of dose of .09 and .05, respectively. CONCLUSION Tube current (dose) has a weak effect on the detection accuracy of small lung nodules in pediatric MDCT. The effect on detection accuracy of a 75% dose reduction was comparable to interobserver variability, suggesting a potential for dose reduction.

[1]  K. Berbaum,et al.  Satisfaction of search in diagnostic radiology. , 1989, Investigative radiology.

[2]  Naichang Yu,et al.  Simulating solid lung nodules in MDCT images for CAD evaluation: modeling, validation, and applications , 2007, SPIE Medical Imaging.

[3]  R Kikinis,et al.  Spiral CT of the chest: comparison of cine and film-based viewing. , 1995, Radiology.

[4]  Williams Da,et al.  A test for differences between treatment means when several dose levels are compared with a zero dose control. , 1971 .

[5]  Rainer Raupach,et al.  The effect of dose reduction and feasibility of edge-preserving noise reduction on the detection of liver lesions using MSCT , 2007, European Radiology.

[6]  Takeshi Johkoh,et al.  Reduced radiation dose helical chest CT: effect on reader evaluation of structures and lung findings. , 2004, Radiology.

[7]  M. Absalon,et al.  Pulmonary nodules discovered during the initial evaluation of pediatric patients with bone and soft‐tissue sarcoma , 2008, Pediatric blood & cancer.

[8]  Ehsan Samei,et al.  Comparison of patient size-based methods for estimating quantum noise in CT images of the lung. , 2009, Medical physics.

[9]  A J Britten,et al.  The addition of computer simulated noise to investigate radiation dose and image quality in images with spatial correlation of statistical noise: an example application to X-ray CT of the brain. , 2004, The British journal of radiology.

[10]  B. J. Winer.  Statistical Principles in Experimental Design , 1992 .

[11]  Willi A Kalender,et al.  An extensible software-based platform for reconstruction and evaluation of CT images. , 2004, Radiographics : a review publication of the Radiological Society of North America, Inc.

[12]  H. Kauczor,et al.  Radiation dose reduction in chest CT: a review. , 2008, AJR. American journal of roentgenology.

[13]  Bernd Hamm,et al.  Low-dose spiral CT: applicability to paediatric chest imaging , 1999, Pediatric Radiology.

[14]  W. Heindel,et al.  Detection of pulmonary nodules at multirow-detector CT: effectiveness of double reading to improve sensitivity at standard-dose and low-dose chest CT , 2004, European Radiology.

[15]  Nevzat Karabulut,et al.  Comparison of low-dose and standard-dose helical CT in the evaluation of pulmonary nodules , 2002, European Radiology.

[16]  M. M. Zhang,et al.  Usefulness of low-dose CT in the detection of pulmonary metastasis of gestational trophoblastic tumours. , 2007, Clinical radiology.

[17]  A R Feinstein,et al.  Context bias. A problem in diagnostic radiology. , 1996, JAMA.

[18]  H Rusinek,et al.  Pulmonary nodule detection: low-dose versus conventional CT. , 1998, Radiology.

[19]  Harold L. Kundel,et al.  Handbook of Medical Imaging, Volume 1. Physics and Psychophysics , 2000 .

[20]  C. Metz.  ROC Methodology in Radiologic Imaging , 1986, Investigative radiology.

[21]  E. Samei,et al.  Experimental comparison of noise and resolution for 2k and 4k storage phosphor radiography systems. , 1999, Medical physics.

[22]  K. Zou,et al.  Multidetector CT of the paranasal sinus: potential for radiation dose reduction. , 2007, Radiology.

[23]  K. Berbaum,et al.  Receiver operating characteristic rating analysis. Generalization to the population of readers and patients with the jackknife method. , 1992, Investigative radiology.

[24]  Jie Zhang,et al.  Paediatric CT: the effects of increasing image noise on pulmonary nodule detection , 2008, Pediatric Radiology.

[25]  Madan M. Rehani,et al.  Effect of reduction in tube current on reader confidence in paediatric computed tomography. , 2005, Clinical radiology.

[26]  D. A. Williams,et al.  A test for differences between treatment means when several dose levels are compared with a zero dose control. , 1971, Biometrics.

[27]  Denis Tack,et al.  Multi-detector row CT pulmonary angiography: comparison of standard-dose and simulated low-dose techniques. , 2005, Radiology.

[28]  A. Leung,et al.  Simulated dose reduction in conventional chest CT: validation study. , 1997, Radiology.

[29]  T M Yelbuz,et al.  Pulmonary nodules: experimental and clinical studies at low-dose CT. , 1999, Radiology.

[30]  Radiation dose in computed tomography of the chest. , 2004, JBR-BTR : organe de la Societe royale belge de radiologie (SRBR) = orgaan van de Koninklijke Belgische Vereniging voor Radiologie.

[31]  E Samei,et al.  Three-dimensional simulation of lung nodules for paediatric multidetector array CT. , 2009, The British journal of radiology.

[32]  Hoen-oh Shin,et al.  Insertion of virtual pulmonary nodules in CT data of the chest: development of a software tool , 2006, European Radiology.

[33]  Kevin S. Berbaum,et al.  Monte Carlo validation of a multireader method for receiver operating characteristic discrete rating data: split-plot experimental design , 1999, Medical Imaging.

[34]  G. Enríquez,et al.  Low-dose high-resolution CT of the chest in children and young adults: dose, cooperation, artifact incidence, and image quality. , 2000, AJR. American journal of roentgenology.

[35]  Jiang Hsieh,et al.  Computer-simulated radiation dose reduction for abdominal multidetector CT of pediatric patients. , 2002, AJR. American journal of roentgenology.

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