Yu Cheng Mi, Presenter: Nothing to Disclose

Xiao Zhu Lin MD, Abstract Co-Author: Nothing to Disclose

Shufeng Fan MD, Abstract Co-Author: Nothing to Disclose

Ying Chen, Abstract Co-Author: Nothing to Disclose

Chunguang Zeng, Abstract Co-Author: Nothing to Disclose

To evaluate the image quality performance of Gemstone Spectral Imaging on cerebral CT subtraction angiography compared with traditional 120 kVp CT scan.

Seventy-four consecutive patients underwent cerebral CTA were randomly enrolled into two groups: control group with conventional 120kVp scan and study group with gemstone spectral imaging scan in artery phase on DISCOVERY CT750HD scanner. The images of each patient were reconstructed into polychromatic images of 120kVp and monochromatic images of 40-140keV. The optimal CNR analysis of monochromatic images was performed on Advantage Workstation 4.5. Then subtraction angiography was executed using conventional 120kVp images and optimal monochromatic images, Volume Rendering images of cerebral artery were reconstructed accordingly. CT values of the cerebral artery, contrast, noise of background, Contrast-Noise-Ratio, Signal-Noise-Ratio of cerebral artery against brain tissue were calculated and compared. Artery delineation and bone removal performance were blindly evaluated by two experienced radiologist using 5 point scale (Excellent:5;Bad:1).

There were two sets of optimal monochromatic images for cerebral angiography: (55.19±2.05)keV and (64.92±1.16)keV. Consistency of the two radiologists is good (Kappa=0.65, u=12.53, p=0.00(<0.05)). There was no significant difference on performance of bone removal between conventional 120kVp and spectral imaging scan(χ2=3.85，p=0.28>0.05). There were significant differences on artery delineation (Ridit analysis: R1140kVp=0.33, R155keV=0.7, R165keV=0.55, R1routine=0.42, χ2=35.52,P=0.00<0.05; R2140kVp=0.31, R255keV=0.68, R265keV=0.57, R2routine=0.44, χ2=33.52,P=0.00<0.05) and CT values of the cerebral artery, contrast, noise of background, Contrast-Noise-Ratio, Signal-Noise-Ratio of cerebral artery against brain tissue (F=38.849, 38.620, 7.995, 11.342, 10.982, p=0.00, <0.05), respectively. CT value, contrast, CNR and SNR of cerebral artery from monochromatic images of 55keV and 65keV were found better than those of conventional 120kVp.

CT spectral imaging with optimal monochromatic images of 55keV can provide high quality images for cerebral artery assessment on CT subtraction angiography compared with traditional 120kVp scan.

Gemstone spectral Imaging can provide high quality images for cerebral artery assessment on cerebral CT subtraction angiography.

Mi, Y, Lin, X, Fan, S, Chen, Y, Zeng, C, Image Quality Comparison between Conventional 120kVp and Gemstone Spectral Imaging on Cerebral CT Subtraction Angiography.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12037792.html