Abstract 5801: Reduction of Blooming Artifact of Calcification with Prototype Fine-Cell Detector Computed Tomography (0.3mm collimation): Comparison with 64-Slice MDCT
Purpose: Severe calcification remains as a major limitation of cardiac CT, due to its blooming artifact. Here we present the novel ‘Fine-cell Detector CT’ (FDCT), which has 0.3125mm detector. Our purpose is to evaluate whether FDCT decreases blooming artifact of calcification compared with 64-slice MDCT by using the slope of profile curve at the border of calcification and iodine.
Materials and Methods: We developed coronary artery phantoms with three different diameters, 3mm, 4mm and 5mm. Within each phantom, calcifications (Tough Bone, Kyoto Kagaku, Japan) with three grades of stenoses (25%, 50% and 75%) were inserted. Diluted iodine (350HU at 120kV) was filled in the lumen of each phantom. Those phantoms in water tank were scanned by both 64-slice VCT (LightSpeed VCT, GE Healthcare) and FDCT with 120kVp, 200mAs, 16row*0.625mm in VCT, 32row*0.3125mm in FDCT. Axial images were reconstructed using Standard kernel with 96mm field-of-view. The longitudinal multiplanar reconstruction images were generated using separate workstation (Advantage Workstation VolumeShare2, GE Healthcare). Profiles of CT value at the border of calcification and iodine were measured vertical to the axis of each phantom. This process was repeated ten times at each grade of stenosis and 30 profile curves obtained from each phantom. Blooming effect of calcification was estimated by slope of the profile curve at the border of calcification and iodine. The slope (HU/mm) was defined as the highest co-efficiency of regression analysis. The slopes of FDCT and VCT were compared.
Results: Total 180 slopes were obtained by regression analysis (averaged R2 = 0.99). In every grade of stenoses within each phantom, the slopes of FDCT were statically higher than that of VCT (p<0.001). (e.g. 980 HU/mm vs 856 HU/mm at 3mm with 50% stenosis, 987 HU/mm vs 802HU/mm at 4mm with 50% stenosis and 975HU/mm vs 795HU/mm at 5mm with 50% stenosis)
Conclusion: FDCT with better spatial resolution decreases blooming artifact of calcification compared with 64-slice MDCT. Fine-cell Detector CT has a potential to improve the evaluation of the lesion with severe calcification.