Carolina Santos Name MD, Abstract Co-Author: Nothing to Disclose

Martine J. Remy-Jardin MD, PhD, Presenter: Nothing to Disclose

Jean-Baptiste Faivre MD, Abstract Co-Author: Nothing to Disclose

Vittorio Pansini MD, Abstract Co-Author: Nothing to Disclose

Nunzia Tacelli MD, Abstract Co-Author: Nothing to Disclose

Jacques Remy MD, Abstract Co-Author: Nothing to Disclose

To compare the radiation dose and image quality of nongated CT angiograms of the chest acquired with single- and dual-source CT technology.

This study was based on the comparative analysis of two-paired populations of 44 patients of less than 80 kg body weight (b.w.), evaluated with dual-source (Definition, Siemens ; Group 1) and single-source (Sensation 64, Siemens; Group 2) CT with an individual adaptation of the kilovoltage according to the patient’s weight. Group 1 patients were scanned with 80 kV (n=5) or 100 kV (n=39) whereas Group 2 patients were scanned with 100 kV (n=14) or 120 kV (n=29). Both groups were otherwise scanned with similar parameters (collimation: 64x0.6mm; pitch: 1.2 to 1.5; rotation time: 0.33s; 4D automatic modulation of milliamperage).

The mean DLP value was statistically significantly lower in Group 1 compared to Group 2 (116.16 +/-53.98 mGy.cm vs 159.53 +/- 78.42 mGy.cm; p=0.0037) with similar subjective image quality and no significant difference in objective image quality assessed by measuring the noise level within the trachea (16.86 +/- 5.33 HU vs 16.42 +/- 5.22 HU; p>0.05) and descending aorta (27.4 +/- 6.33 HU vs 26.54 +/- 6.81 HU; p>0.05). The mean BMI of patients scanned at 100 kV was significantly higher in Group 1 (22.03 +/- 3.12 kg/m2) than Group 2 (19.15 +/- 2.26 kg/m2; p=0.0024) with similar subjective and objective image quality. The levels of diagnostic reference (i.e., DLP values of 75% of CT scans) in the studied population were 132 mGy.cm in Group 1 and 208 mGy.cm in Group 2.

Dual-source CT allows more frequent use of low kilovoltages than single-source CT without impairment in image quality, thus reducing the overall radiation dose delivered during standard CT angiograms of the chest.

Low kilovoltage scanning is an efficient means for radiation dose reduction, applicable to routine nongated CT angiography of the chest without alteration in image quality.

Santos Name, C, Remy-Jardin, M, Faivre, J, Pansini, V, Tacelli, N, Remy, J, Radiation Dose during Nongated MDCT Angiography of the Chest: Comparison between Single- and Dual-source CT Technology.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011212.html