双能CT迭代去金属伪影重建算法联合虚拟单能成像在腰椎金属内固定伪影抑制中的应用及能量优化OA

Objective To investigate the application of dual-energy CT iterative metal artifact re-duction reconstruction algorithm(DE-iMAR)combined with virtual monochromatic imaging(DE Mono+)for metal artifact suppression in lumbar spinal instrumentation and to identify the optimal reconstruction energy level.Methods This retrospective study enrolled 105 patients who underwent CT examina-tion after lumbar spinal instrumentation.All patients were scanned using a third-generation dual-source CT scanner(Siemens SOMATOM).The original dual-energy CT mixed images were acquired(group A),and three reconstruction approaches were applied:DE-iMAR alone(group B),DE Mono+alone(group C),and DE-iMAR combined with DE Mono+(group D).Two radiologists with more than 5 years of experience independently evaluated image quality and artifact scores using a double-blind method.The subjective scores,CT values of the psoas major muscle at the most se-vere artifact level and at artifact-free level were compared among the four groups under different en-ergy conditions.The inter-observer agreement for image quality and artifact scoring was assessed.The subjective scores,artifact scores,subjective scores at the most severe artifact site,and artifact index(AI)values were compared among the four groups.Results At 130 keV,the subjective scores of groups C and D were significantly higher than those at 120 kVp and at 40,70,100,160,and 190 keV(P＜0.05).At 40-190 keV,group D had significantly higher subjective scores than group C at the same energy levels(P＜0.05);at 120 kVp,group D had significantly higher sub-jective scores than groups A and B(P＜0.05).At 120 kVp,the CT values of the psoas major mus-cle at the most severe artifact level in groups A and B were significantly higher than those at the arti-fact-free level(P＜0.05).At 120 kVp and at 40,70,100,160,and 190 keV,the CT values at the most severe artifact level in groups C and D were significantly higher than those at the artifact-free level(P＜0.05).At 40-190 keV,the CT values of the psoas major muscle at both the most severe artifact level and the artifact-free level in group D were significantly lower than those in group C(P＜0.05).At 120 kVp,the CT values at both the most severe artifact level and the artifact-free level in group D were significantly lower than those in groups A,B,and C(P＜0.05).At 130 keV,groups C and D showed the optimal image quality and artifact suppression;therefore,subsequent analyses were performed at this energy level.The intraclass correlation coefficients(ICC)for image quality and artifact scoring by the two radiologists were all over 0.8,indicating good agreement(P＜0.05).The subjective scores of group D were significantly higher than those of groups A,B and C,with groups B and C scoring higher than group A(P＜0.05).The artifact scores of group D were significantly lower than those of groups A,B,and C,with groups B and C scoring lower than group A(P＜0.05).The subjective scores of group D for soft tissue,metal-bone interface,and e-rector spinae were significantly higher than those of groups A,B,and C,with groups B and C sco-ring higher than group A(P＜0.05).The AI values of region of interest(ROI)1,ROI 2,and ROI 3 in group D were significantly lower than those in groups A,B,and C,with groups B and C scoring lower than group A(P＜0.05).Conclusion The combination of DE-iMAR and DE Mono+demonstrates application value in reducing metal artifacts in lumbar spinal instrumentation and significantly improves CT image quality after lumbar spinal instrumentation,providing more reli-able imaging evidence for clinical diagnosis.