Kolja Thierfelder MD, MSc, Presenter: Nothing to Disclose

Lukas Havla, Abstract Co-Author: Nothing to Disclose

Sebastian Ekkehard Beyer, Abstract Co-Author: Nothing to Disclose

Felix G. Meinel MD, Abstract Co-Author: Nothing to Disclose

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

Wieland H. Sommer MD, Abstract Co-Author: Nothing to Disclose

Recently introduced dynamic CT angiography (dCTA) provides additional information on cerebral hemodynamics, but small differences in the time delay of maximum enhancement are hard to detect. Our aim was to evaluate a new method of displaying dCTA datasets in which the time of maximum enhancement is displayed in a range of colors (color-coded CT angiography, cCTA) in different types of acute ischemic stroke.

Our sample comprised 16 patients who underwent multiparametric CT due to suspected stroke. MRI-confirmed diagnoses were M1- (6), ACI- (4), both M1- and ACI- (1), and carotid t occlusion (3). Two patients had no cerebral pathology. cCTA was reconstructed from whole-brain CT perfusion raw data that were acquired on a 128-slice CT with one scan acquired every 1.5s. The delay of vessel enhancement was quantified using the time-to-maximum (Tmax) of the residue functions. Tmax parameters were color-coded and then filtered. Non-enhancing areas were masked. cCTA is a composite image of angiographic data superimposed by colored Tmax maps.Two experienced readers evaluated whether cCTA provided additional information when compared to conventional CTA alone with respect the Circle of Willis, M1-segment, M2-segement, and leptomeningeal collaterals. The visualization of the collateralization and the diagnostic confidence in determining occlusion site were rated using maximum intensity projections of 20, 40, and 60mm slab thicknesses on 5-point Likert scales.

The combined use of CTA and cCTA in comparison to CTA alone provided additional information in the assessment of the Circle of Willis in 6/16, the M1-segment in 12/16, the M2-segment in 14/16, and the collateralization status in 15/16 of the patients. Leptomeningeal collaterals were most favorably visualized on the 40- (3.53±0.63), followed by the 60- (3.36±0.50), and the 20mm-MIP (2.92±0.81). The occlusion site was most favorably represented on the 20- (2.71±1.12), followed by the 40- (2.54±1.09), and the 60mm-MIP (1.87±1.20). 

cCTA yields a comprehensive and easy-to-read overview of the cerebral hemodynamics. It provides additional information with respect to collateralization status and occlusion site.

cCTA is a simple and robust technique that demonstrates cerebral hemodynamics at a glance. It might be beneficial for a fast and reliable assessment of the collateralization status in patients with acute ischemic stroke.

Thierfelder, K, Havla, L, Beyer, S, Meinel, F, Reiser, M, Sommer, W, Color-coded Cerebral CT Angiography: Technical Feasibility and Benefits in Patients with Acute Ischemic Stroke.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011450.html