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Second-Generation Dual-Energy Computed Tomography of the Abdomen: Radiation Dose Comparison With 64- and 128-Row Single-Energy Acquisition

De Cecco, Carlo Nicola MD*; Darnell, Anna MD; Macías, Napoleón MD; Ayuso, Juan Ramón MD; Rodríguez, Sonia MD; Rimola, Jordi MD; Pagés, Mario MD; García-Criado, Ángeles MD; Rengo, Marco MD*; Muscogiuri, Giuseppe MD*; Laghi, Andrea MD*; Ayuso, Carmen MD

Journal of Computer Assisted Tomography:
doi: 10.1097/RCT.0b013e318291f6a0
Abdominal Imaging

Purpose: This study was designed to compare the radiation dose in abdominal dual-energy (DE) and single-energy (SE) acquisitions obtained in clinical practice with a second-generation DE computed tomography (DECT) and to analyze the dose variation in comparison with an SE acquisition performed with a 64-row SECT (SECT).

Methods: A total of 130 patients divided into 2 groups underwent precontrast and portal abdominal 128-row CT examination. In group A, DE portal acquisition was performed using a detector configuration of 2 × 40 × 0.6 mm, tube A at 80 kVp and a reference value of 559 mAs, tube B at 140 kVp and a reference value of 216 mAs, pitch 0.6, and online dose modulation; group B underwent SE portal acquisition using a detector configuration of 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. Group C consisted of 32 subjects from group A previously studied with 64-row SECT using the following parameters: detector configuration 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. In each group, the portal phase dose-length product and radiation dose (mSv) were calculated and normalized for a typical abdominal acquisition of 40 cm.

Results: After normalization to standard 40-cm acquisition, a dose-length product of 599.0 ± 133.5 mGy · cm (range, 367.5 ± 1231.2 mGy · cm) in group A, 525.9 ± 139.2 mGy · cm (range, 215.7–882.8 mGy · cm) in group B, and 515.9 ± 111.3 mGy · cm (range, 305.5–687.2 mGy · cm) in group C was calculated for portal phase acquisition.

A significant radiation dose increase (P < 0.05) was observed in group A (10.2 ± 2.3 mSv) compared with group B (8.9 ± 2.4) and group C (8.8 ± 1.9 mSv). No significant difference (P > 0.05) was reported between SE 64- and 128-row acquisitions. A significant positive correlation between radiation dose and body mass index was observed in each group (group A, r2 = 0.59, P < 0.0001; group B, r2 = 0.35, P < 0.0001; group C, r2 = 0.20, P = 0.0098).

Conclusions: In clinical practice, abdominal DECT acquisition shows a significant but minimal radiation dose increase, on the order of 1 mSv, compared with 64- and 128-row SE acquisition. The slightly increased radiation dose can be justified if the additional information obtained using a spectral imaging approach directly impacts on patient management or reduce the overall radiation dose with the generation of virtual unenhanced images, which can replace the precontrast acquisition.

Author Information

From the *Department of Radiological Sciences, Oncology and Pathology, University of Rome “Sapienza”–Polo Pontino, Latina, Italy; and †Department of Radiology, Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain.

Received for publication October 22, 2012; accepted March 10, 2013.

Reprints: Carlo Nicola De Cecco, MD, Department of Radiological Sciences, Oncology and Pathology, University of Rome “Sapienza”–Polo Pontino, Via Franco Faggiana, 34. 04100 Latina, Italia (e-mail:

All authors have no conflict of interest to disclose relevant to this investigation.

© 2013 by Lippincott Williams & Wilkins