Mathias Georg Ludwig Cohnen MD, Presenter: Nothing to Disclose

Sarah Assadi, Abstract Co-Author: Nothing to Disclose

Hans-Joerg Wittsack PhD, Abstract Co-Author: Nothing to Disclose

Ludger Wilhelm Poll MD, Abstract Co-Author: Nothing to Disclose

Andreas Saleh MD, Abstract Co-Author: Nothing to Disclose

Klaus Muskalla MD, Abstract Co-Author: Nothing to Disclose

Ulrich Moedder MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To assess patient radiation exposure in typical Multi-Detector Row CT (MDCT) protocols for imaging of the head in ischemic cerebral disease (“stroke imaging”).

Scanning protocols of MDCT of the head, of cerebral and cervical vessels, as well as perfusion MDCT protocols, respectively, were simulated using a “Somatom Sensation Cardiac 64” (Siemens Medical Solutions, Erlangen, Germany). Standard MDCT of the head comprised of sequential scanning using a collimation of 20x1.2 mm. MDCT-angiographic studies were performed with 64x0.6 mm. MDCT-perfusion studies of the brain used 20x1.2 mm detector configuration with different tube currents (270, 200 mAs) as well as tube potentials (80, 120 kV). Effective doses were derived from LiF-TLD-measurements at several organ sites using an Alderson-Rando phantom.

Effective doses were 1.7 mSv for standard MDCT of the head, 1.9 mSv for MDCTA of intracranial vessels, 2.8 mSv for MDCTA of cervical vessels, respectively. With different parameters, effective dose varied between 1.1 and 5.0 mSv for MDCT-perfusion scanning of the brain. In perfusion MDCT, local doses in the area of the primary beam ranged between 21 and 325 mGy.

The effective dose in combined 64-detector row CT of the head, the cerebral or cervical vessels, and cerebral perfusion (“stroke imaging”) may result in up to 9.5 mSv with possible local doses of up to 350 mGy depending on the chosen examination parameters.

Particularly in case of repeated examinations physicians should be aware which method, CT or MRI, is adequate for patients with acute stroke including side-effects and informed consent.

Cohnen, M, Assadi, S, Wittsack, H, Poll, L, Saleh, A, Muskalla, K, Moedder, U, et al, , Radiation Exposure of the Patient in Multi-Detector Row CT Stroke Imaging: Combination of Head CT, CT Angiography, and CT Perfusion.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4429247.html