Ulrich Linsenmaier MD, Presenter: Nothing to Disclose

Stefan Wirth MD, Abstract Co-Author: Nothing to Disclose

Daniel Maxien MD, Abstract Co-Author: Nothing to Disclose

Michael Karl Scherr MD, Abstract Co-Author: Nothing to Disclose

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Markus Koerner MD, Abstract Co-Author: Research grant, General Electric Company

Lindis Brummund, Abstract Co-Author: Nothing to Disclose

Do consecutive dose reduction and new iterative image reconstruction in MDCT allow for a dose neutral replacement of CR in diagnosis of the cervical spine in Emergency Radiology?

On a 64 row MDCT scanner with gemstone detector (HD750, GE Healthcare, Waukesha, Milwaukee) a standard protocol (120 kV, modulated tube current, 80-300 mA) and four consecutive dose reduced protocols, (I)10-80, (II)10-60, (III)10-40 and (IV)10-20mA, were obtained. All scans were calculated with and without Adaptive Statistical Iterative Reconstruction (ASIR) and soft tissue and bony kernels. After IRB approval intact human cadavers were studied undergoing virtual autopsy. A total of 160 tudies were evaluated for image noise [SD HU] and four readers rated the image quality at level of C3 and C7 on a semiquantitative scale [0 (non diagnostic) to 4 (fully diagnostic)]. Effective dose estimations [mSv] of all studies were calculated using CTDI, scan length and DLP. All results were compared to the standard protocol. Effective dose (a.p., lat.) of the digital CR system (ADC, AGFA, Germany) was measured with a Alderson phantom. Wilcoxon test was used for the statistical tests.  

Image noise increased for spongious (+15%) and remained unchanged (+/- 2%) with cortical bone. Cortical bone was fully diagnostic (score 4) at C3 for all protocols and slightly impaired at C7 (score 3) for dose levels I (10/80) and II (10/60 mA) and non diagnostic (score 1-2; p< 0.05) for levels III and IV.Spongious bone was non diagnostic at C3 with dose level IV (10-20mA) (p <.02) and at C7 with level III (10/40) and IV (10/20 mA). Effective doses were 1.1 mSv for standard and 0.62, 0.33, 0.27, 0.18 mSv for levels I-IV, respectively and 0.9mSv for CR (2 planes). ASIR did not significantly improve the results for dose reduced protocols.  

MDCT using low dose protocols can replace CR at a comparable dose level.

Low dose MDCT provides diagnostic image quality at a comparable dose level and could replace CR films in the evaluation of bony structures.

Linsenmaier, U, Wirth, S, Maxien, D, Scherr, M, Reiser, M, Koerner, M, Brummund, L, Replacing Conventional Radiographs of the Cervical Spine: Low Dose MDCT Using Consecutive Dose Reduction and Iterative Image Reconstruction—A Cadaver Study.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010245.html