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Performance of Iterative Reconstruction and Automated Tube Voltage Selection on the Image Quality and Radiation Dose in Abdominal CT Scans

Desai, Gaurav S. MD; Fuentes Orrego, Jorge M. MD; Kambadakone, Avinash R. MD; Sahani, Dushyant V. MD

Journal of Computer Assisted Tomography: November/December 2013 - Volume 37 - Issue 6 - p 897–903
doi: 10.1097/RCT.0b013e3182a73fa6
Abdominal CT Techniques and Dose Optimization

Objective: To study the impact of sinogram-affirmed iterative reconstruction (SAFIRE) and concurrent application of automated tube voltage selection (ATVS) on image quality (IQ) and radiation dose.

Methods: A phantom was scanned using various computed tomography (CT) parameters (kV, 80–120; mAs, 50–200). Abdomen contrast-enhanced CT (CECTs) in 170 adults were performed using dose-modified protocols: in 145 patients (group I), ATVS was applied (mAs, 111–649); in 25 (group II), the kV was fixed at 120 (reference mAs, 150). In 95 patients, standard-dose (SD) scan was available. Two readers evaluated the IQ of filtered back projection (FBP) and SAFIRE (levels 1, 3, and 5) images.

Results: In phantom, nonlinear drop in noise with increasing strengths of IR (levels S1–S5) was noted. The dose-modified IR scan was rated diagnostic in all 170 patients, with IQ score comparable to that of SD-FBP (P = 0.3). Lower kV (100/80) was prescribed by ATVS in 70% examinations in group I. In comparison with SD-FBP, the mean dose in CT dose index in group I (IR, 3.2 mGy; SD-FBP, 13.02 mGy; P < 0.0001) and in group II (IR, 4.8 mGy; SD-FBP, 11.8 mGy; P < 0.001) was 75.4% and 59.3% lower.

Conclusions: Use of SAFIRE and ATVS provides diagnostic quality images at 59.3% to 75.4% reduced dose compared with SD-FBP scan.

From the Department of Radiology, Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, Boston, MA.

Received for publication May 2, 2013; accepted July 19, 2013.

Reprints: Dushyant Sahani, MD, Division of Abdominal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114 (e-mail: dsahani@partners.org).

The study was not funded by any agency or CT manufacturer.

The authors report no conflicts of interest.

© 2013 by Lippincott Williams & Wilkins