Ulrike Wiesspeiner MD, Presenter: Nothing to Disclose

Georg F. Stuecklschweiger PhD, Abstract Co-Author: Nothing to Disclose

Robert Vollmann, Abstract Co-Author: Nothing to Disclose

Helmut Guss, Abstract Co-Author: Nothing to Disclose

Rudolf Stollberger DPhil, Abstract Co-Author: Nothing to Disclose

Franz Ebner MD, Abstract Co-Author: Nothing to Disclose

To optimize 4D-CT-DSA for high-resolution cerebral arteriography with lowest possible effective radiation dose.

Inclusion of fifty-nine patients (39 females, mean 54,0 years and 20 males, mean 56,6 years) who had previous aneurysm surgery. 320 rows Volume-CT-Technology (Aquilion-One, Toshiba) and contrast medium with 400mg Iodine/ml conc. were used. Scanning protocol: single slice (mask) 80/100 (kV/mA); diagnostic scans (3 rotations): 80/300 (kV/mA), slice ThK: 0,5 mm, FOV: 180 or 240 mm, scan range: 120-128 cm. Bolus timing was performed to determine individual arrival times. Test bolus: 10 ml CM and saline flush, diagnostic bolus: 50ml CM and saline flush. Diagnostic criteria to assess vessel anatomy: M3 and/or M4 segments of the middle cerebral artery (MCA) and terminal segment of the pericallosal artery (PA). Image corruption by venous overlay was assessed. Vessel contrast: excellent / good / poor (non-diagnostic). Dosimetry: in-vivo measurements with lithium-fluorid- thermoluminescent dosimeters (TLD)

Delineation of arterial segments: contrast filling of terminal segment of the PA in 96%, 2/3 in 4%. Contrast filling of the MCA was present within the 4th segment in 91% and only in the 3rd segment in 9%. Vessel Contrast: excellent in 77%, good (diagnostic) in 20% and poor (non-diagnostic) in 3%. Bolus-Timing was considered as exactly in 88%, early (but diagnostic) in 11% and late in 1% (venous overlay). In-vivo-Dosimetry: Mean DLP: FOV (180 cm mean value): 757,6 mGy•cm; FOV (240 cm mean value) 977,5, mGy•cm. Mean effective doses (both FOV): 1,87 mSv (SD 0,23).

4D-CT-DSA with three rotations can achieve high contrast in cerebral arteries (4th segment of MCA and terminal segment of PA) without enhancement of the deep venous system. Effective radiation dose can be confined along with established reference levels for head CT at the level of 2mSv.

4D-CT-DSA has the capability to act as follow-up imaging modality in patients undergoing surgical clipping of cerebral aneurysms in order to detect neck remnants or reperfusion.

Wiesspeiner, U, Stuecklschweiger, G, Vollmann, R, Guss, H, Stollberger, R, Ebner, F, The Circle of Willis on Dynamic Volume CT Angiography: Bolus Timing, Vessel Delineation, and Radiation Dose.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015564.html