The Clinical Application Of Monoenergetic Technique Of Dual-energy CT In Reducing Artifacts Caused Lumbar Spinal Internal Fixation And Three-dimensional Reconstruction

0bjective The aim of the study was to assess the performance and diagnostic valueof a dual energy CT approach to reduce metal artifacts in subjects with lumbar spinalinternal fixation and three-dimensional reconstruction.Methods57cases of patients with lumbar spinal internal fixation are examinated bydual source CT dual energy.80KV,140KV and1set of average weighted of120KVhybrid energy images are collected after one-time scanning. Monoenergetic softwarewas used to post-process, reconstruct9monoenergetic image the space of10keVbetween60keV～140keV energy group. In each group of monoenergetic image andthe mixture of average weighted120KV energy image, area of interest (ROI) wasselected in vertebral body (trabecular bone) of metal artifacts heaviest level line,measure CT value and SD value, then recorded, calculated signal-to-noise ratio (SNR)value under different photon energy. LSD t-test was applied to determine CT valueand noise. Two radiologists evaluated and rated the reformatted images with MPR,SSD and VRT according to the following3scale. Good, mild artifact, goodvisualization of bony structures and no artifact; assessable, moderate artifact;nonassessable, with marked artifact;2-test was used to perform statistical analysis ofimage quality for MPR, SSD and VRT.Results There were fewer artifacts on the images due to the application ofmonoenergetic technique in dual-energy CT. Nine groups of monoenergetic imagesfrom60keV to140keV compare to average weighted120KV images, there was nosignificant difference among CT value and noise value in60keV（P>0.05）. From70keV to140keV, there was significant difference among CT value and noise value（P<0.05）. Two side-by-side group of single energy CT image under different tubevoltage value was compared to. There was significant difference among CT value from60keV to130keV（P <0.05）. There was no significant difference among CTvalue between130keV and140keV（P>0.05）. There was significant differenceamong noise value from60keV to110keV（P <0.05）. There was no significantdifference among noise value from110keV to140keV（P>0.05）. There was nosignificant difference in the signal-to-noise ratio. Three kinds of three-dimensionalreconstruction are no serious artifact. MPR method without artifacts of45cases,12cases of artifacts is lighter;47cases of SSD method without artifacts，10cases ofartifacts is lighter;57cases of VRT have shown good, three kinds ofthree-dimensional reconstruction image quality difference have statisticallysignificance（P <0.05）.Conclusion Dual-source CT single spectrum technology can significantly reducemetal artifacts of lumbar spinal internal fixation.130keV～140keV images displaythe least artifact. Monoenergetic images at110keV have the highest diagnoseticquality. VRT has fewer artifacts than MPR and SSD.