Daniele Marin MD, Presenter: Fellowship funded, Bracco Group

Rendon C. Nelson MD, Abstract Co-Author: Consultant, General Electric Company Research support, Bracco Group Research support, Covidien AG Speakers Bureau, Siemens AG

Chris Proctor BSRT, Abstract Co-Author: Employee, General Electric Company

Sebastian Tobias Schindera MD, Abstract Co-Author: Nothing to Disclose

The advantages of higher contrast of low kVp images tends to be offset by the inherent high noise, compared to high kVp images. Our purpose is to retrospectively assess the effect of an adaptive statistical iterative reconstruction (ASIR) algorithm for improving the image quality of low energy (80 kVp) technique on abdominal multidetector computed tomography (MDCT).

The study cohort comprised 10 patients (6 men, 4 women; mean age, 63; age range, 51-77 years) who underwent an abdominal dual energy, 64-slice MDCT scan (LightSpeed VCT; GE Healthcare) during the late hepatic arterial phase. By using a vendor-provided software (Volume Dual Energy; GE Healthcare) that allows for the nearly simultaneous delivery of two different kilovoltage energies in a single acquisition, two separate imaging settings (80 kVp / 540 mAs and 140 kVp / 308 mAs) were acquired. Besides the standard reconstruction algorithm, the low energy (80 kVp) image set was also processed with the ASIR algorithm (GE Healthcare) and a noise reduction level set at 40. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) relative to the muscle were measured for the aorta, liver, and pancreas, and were compared for the 80-, 140-, and ASIR-processed 80-kVp image sets. Mean image noise levels were also compared between the three image sets. The analysis of variance (ANOVA) test was performed for verification of statistically significant differences (P < 0.05).

The image noise decreased from 20.4 to 15.6 HU when the baseline non-processed 80 kVp image set was reconstructed with the ASIR algorithm (P < 0.001). At the same time, the ASIR-reconstructed image set yielded the highest SNR and CNR for aorta, liver, and pancreas compared to either baseline non-processed 80- or 140-kVp image sets (P < 0.001).

The ASIR algorithm can substantially reduce image noise of a low energy (80 kVp) technique, which results in improved image quality compared to either baseline non-processed 80- or 140-kVp image sets.

By substantially improving image quality, the ASIR algorithm can increase the effectiveness of a low tube voltage technique for abdominal MDCT applications.

Marin, D, Nelson, R, Proctor, C, Schindera, S, Low Tube Voltage, High Tube Current Multi–Detector Row CT of the Abdomen: Improved Image Quality with an Adaptive Statistical Iterative Reconstruction Algorithm.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6017529.html