[Value of Monochromatic Imaging on Spectral Detector CT in Metal Artifact Reduction of Denture Implants]

Objective To evaluate the role of monochromatic imaging in reducing metal artifacts and improving image quality in patients with denture implants undergoing head/neck plain CT. Methods Forty patients with denture implants undergoing head/neck plain CT on a dual-layer spectral detector CT were enrolled. The conventional and monochromatic 110 keV images were reconstructed from the same acquisition. The regions of interests (ROIs) were placed on the artifact streak (CT1),the soft tissue affected by the artifact (CT2),and the unaffected tissue (CT3). The artifact index (AI) and standard deviation (SD) were calculated. The image quality was compared.Results The attenuation of CT1 was significantly improved on monochromatic images than on conventional images [-195.00 (-700.40,44.80) vs. -336.50 (-1024.00,-77.00),P=0.00]. The attenuation of CT2 was significant different between monochromatic and conventional images [46.10 (-0.20,91.60) vs. 102.80 (4.60,210.20),P=0.00]. The difference between CT2 and CT3 was significantly smaller on monochromatic images than on conventional images [14.55 (0.00,44.00) vs. 51.30 (0.30,168.30),P=0.00]. The SD of CT2 was significantly smaller on monochromatic images than on conventional images [14.75 (7.80,35.00) vs. 23.25 (7.60,56.00),P=0.00]. The AI was significantly improved by monochromatic imaging [12.76 (3.53,34.14) vs. 19.00 (2.43,54.32),P=0.00]. Conclusion The monochromatic imaging can effectively reduce the artifacts caused by denture implants and improve image quality on head/neck plain CT.