Mathias Meyer, Presenter: Nothing to Disclose

Holger Haubenreisser, Abstract Co-Author: Nothing to Disclose

Sonja Sudarski MD, Abstract Co-Author: Nothing to Disclose

Florian Lietzmann, Abstract Co-Author: Nothing to Disclose

Lothar R. Schad PhD, Abstract Co-Author: Nothing to Disclose

Stefan Oswald Schoenberg MD, PhD, Abstract Co-Author: Institutional research agreement, Siemens AG

Thomas Henzler MD, Abstract Co-Author: Nothing to Disclose

To prospectively evaluate radiation dose and image quality of a third generation 2x192 slice dual-source CT (DSCT) without z-axis filter behind the patient and a 0.4x0.5mm2 focal spot for temporal-bone CT.

Forty-five patients were either scanned on a 1st, 2nd or 3rd generation DSCT in an ultra-high-resolution (UHR) temporal-bone imaging mode. Detector collimation on the first two generation DSCTs was 16x0.6 mm using a z-axis UHR filter, leading to an effective collimation of 16x0.3 mm and a reduced z-axis radiation dose efficiency of approximately 50%. On the 3rd generation DSCT system the tighter focal spot of 0.2mm2 allows to omit the necessity for an additional z-axis-filter. 0.4 mm images were reconstructed using standard filtered-back-projection (FBP) or iterative reconstruction (IR) technique for the first two generations of DSCT and a novel model based IR algorithm for the 3rd generation DSCT. Objective image quality was evaluated for identical regions-of-interest and subjective image quality was evaluated on a 5-point Likert scale. Radiation dose parameters were assessed and compared between the three DSCT systems. Comparisons between the groups were analyzed with two-way ANOVA or Wilcoxon-Rank-Sum Test depending on the distribution of the data.  

The statistically significantly highest subjective and objective image quality was found for the 3rd generation DSCT when compared to the 1st or 2nd generation DSCT systems (subjective image quality: 3rd generation DSCT 5[5-5], 2nd generation DSCT 4[4-4], 1st generation DSCT 3[2-3] all p<0.0001). Total effective dose was 63%/39% lower for the 3rd generation system when compared to the 1st and 2nd generation DSCT (0.25±0.04 mSv vs. 0.67±0.04 mSv and 0.41±0.04 mSv; p<0.0001 respectively).

Temporal bone imaging without z-axis-UHR-filter and a novel third generation IR algorithm allows for significantly higher image quality, while lowering effective dose when compared to the first two generations of DSCTs.

UHR temporal bone imaging with a 3rd generation DSCT allows for significantly lower radiation doses, while improving image quality, which is especially important in order to reduce organ radiation dose.

Meyer, M, Haubenreisser, H, Sudarski, S, Lietzmann, F, Schad, L, Schoenberg, S, Henzler, T, Initial Results of a 3rd Generation Dual Source CT System Using Only an In-Plane Comb Filter for Ultra-high Resolution Temporal Bone Imaging  .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011162.html