Christopher Herzog MD, Presenter: Nothing to Disclose

Denise M. Mulvihill MD, Abstract Co-Author: Nothing to Disclose

Shaun A Nguyen MD, Abstract Co-Author: Nothing to Disclose

Bernhard Schmidt PhD, Abstract Co-Author: Employee, Siemens AG

Giancarlo Savino MD, Abstract Co-Author: Nothing to Disclose

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

Philip Costello MD, Abstract Co-Author: Speakers Bureau, General Electric Company Speakers Bureau, Bracco Group

U. Joseph Schoepf MD, Abstract Co-Author: Research grant, Schering AG (Berlex Inc) Research grant, Bracco Group Research grant, General Electric Company Research grant, Schering AG (MEDRAD, Inc) Research grant, Siemens AG Consultant, Schering AG (Berlex Inc) Consultant, Bracco Group Consultant, General Electric Company Consultant, Siemens AG Consultant, PAION AG

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To assess the effect of weight-based scan protocols and automatic tube current modulation (ATCM) on tube-current-time product values and image quality at cardiovascular pediatric 64-slice CTA.

The need for approval of this HIPAA-compliant retrospective study was waived by our IRB. Our 64-slice CT protocols use a weight based algorithm to determine nominal tube current settings with 80, 100 and 120 kV. ATCM was used for each case. Comparison was made to 16-slice MDCT with 120kVp tube voltage and 120 mAs tube current and to the selected nominal mAs-values, which would have been delivered without ATCM. Two radiologists independently rated image quality on a 5-point scale. Image noise was objectively assessed by measuring the standard deviation in HU within four different regions of interest. Findings at CT were clinically correlated with cardiac ultrasound, angiography or surgery.

Thirty-eight 64-slice and thirty 16-slice MDCT scans were evaluated. Mean diagnostic quality for 64-slice MDCT was rated at 3.7 (range 3-4.4), mean image noise was 9.1 HU STD (range 3.3-15.9). For 16-slice MDCT results were similar. Scanning with ATCM significantly (p<0.05) reduced tube current time-product values as compared to scanning without ATCM (-57.8% / 54.1/128mAs) or 16-slice MDCT (-47.9% / 54.1/104.37mAs) respectively. mAs-values were significantly (p<0.05) lower for 80kVp than for 100kVp or 120kVp scans, whereas image quality and image noise was similar. Agreement between MDCT and clinical findings was excellent.

ATCM combined with low tube voltage settings significantly reduce radiation exposure and are thus generally recommended in pediatric cardiovascular 64-slice CT.

In MDCT pediatric cardio-vascular imaging radiation dose can be significantly reduced without compromising image quality by combining low voltage scan protocols with automated tube current modulation.

Herzog, C, Mulvihill, D, Nguyen, S, Schmidt, B, Savino, G, Vogl, T, Costello, P, Schoepf, U, et al, , et al, , Pediatric Cardiovascular 64-slice CT Angiography: Radiation Dose Reduction by Automated Anatomical Tube Current Modulation.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4441784.html