Ralf W. Bauer MD, Presenter: Research Consultant, Siemens AG Speakers Bureau, Siemens AG

Lara Holthaus BSC, Abstract Co-Author: Nothing to Disclose

Boris Schell MD, Abstract Co-Author: Nothing to Disclose

Martin Beeres MD, Abstract Co-Author: Nothing to Disclose

Thomas Josef Vogl MD, PhD, Abstract Co-Author: Nothing to Disclose

Josef Matthias Kerl MD, Abstract Co-Author: Research Consultant, Siemens AG Speakers Bureau, Siemens AG

Patients suffering from malignant lymphomas regularly undergo CT of the neck with relevant dose exposure for the evaluation of lymph node status. We compared a novel high-pitch dual source CT (DSCT) protocol with our standard single source CT examination protocol in terms of dose and conspicuity of cervical lymph node levels.

We compared data from 30 patients who underwent contrast-enhanced high-pitch DSCT (group 1) of the neck for staging of malignant lymphoma to 30 patients who underwent regular single source CT (group 2) on the same CT scanner (Definition Flash, Siemens). Scan protocols were as follows: group1: dual source mode, 128x0.6 mm collimation, tube voltage/current of 120 kV/180 mAs on tube A and B, rotation time 0.28 s, pitch 3.0; group 2: single source mode, 128x0.6 mm collimation, tube voltage/current of 120 kV/180 mAs, rotation time 1.0 s, pitch 0.8. Automated tube current modulation was used in both groups. Images were reconstructed at 2 mm section width with 2 mm increment and a medium soft convolution kernel (B30f). CTDIvol and DLP as measure of dose and background noise (BN) as measure of objective image quality were compared using Wilcoxon-Mann-Whitney-U test. Overall subjective diagnostic image quality and artifact burden were rated by two radiologists from 1 to 5 (1 = excellent image quality/no artifacts, 5 = no reliable diagnosis possible/heavy artifacts).

Mean CTDIvol (5.6±0.9 mGy vs. 12.9±1.1 mGy) and DLP (182±34 mGycm vs. 357±39 mGycm) were significantly (p = 0.003) lower for group 1 compared to group 2. Mean BN was significantly higher for group 1 (6.7±1.4 HU vs. 4.2±0.4 HU; p = 0.001). However, this did not affect diagnostic image quality. Mean subjective image quality (1.2±0.4 vs. 1.1±0.3) and artifact burden (1.7±0.7 vs. 1.3±0.5) was not rated significantly different between both groups (p = 0.54 and p = 0.29).

High-pitch DSCT of the neck allows for a significant reduction of patient dose while diagnostic image quality is preserved in patients undergoing cervical lymph node staging for malignant lymphoma. Especially in young adults radiation delivered to critical organs like thyroid gland and eye lens is of important matter.

High-pitch DSCT of the neck allows for significant reduction of patient dose for lymphoma staging.

Bauer, R, Holthaus, L, Schell, B, Beeres, M, Vogl, T, Kerl, J, Dose and Image Quality of High-Pitch Dual-Source CT for the Evaluation of Cervical Lymph Node Status: Comparison to Regular 128-slice Single-Source CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034364.html