双能量CT联合金属伪影削减算法抑制股骨柄假体金属伪影的模型研究
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摘要
目的:通过体模研究,评价双能量CT扫描获得的虚拟单色谱图像(VMS)联合金属伪影削减(MAR)算法抑制股骨柄假体金属伪影的效果。方法:将人工股骨柄假体用细绳悬挂在水箱中心。以不同管电压(80、100、120、140 kVp)单能量CT(SECT)及不同管电流(200、484 mA)下的双能量CT(DECT)扫描假体。扫描设备选择单球管,单层探测器CT扫描仪。利用单球管双电压快速切换的双能量扫描获得的数据重建40、90、140 keV单色谱图像(VMS),及经过金属伪影抑制算法处理的40、90、140 keV单色谱图像(VMS+MAR)。对全部图像(16组)进行质量评价,包括伪影面积(AA),伪影指数(AI)。结果:16组图像(140 kVp、120 kVp、100 kVp、80 kVp、40 keV 485 mA、40 keV 485 mA MAR、90 keV 485 mA、90 keV 485 mA MAR、140 keV 485 mA、140 keV 485 mA MAR、40 keV 200 mA、40 keV 200 mA MAR、90 keV 200 mA、90 keV 200 mA MAR、140 keV 200 mA、140 keV 200 mA MAR)伪影面积分别为787、1088、1499、2133、5664、650、665、172、279、157、7603、886、803、238、423、172 mm~2,伪影指数分别为22.75、33.65、58.58、92.55、195.18、3.53、23.38、0.35、7.88、0.05、230.28、4.95、24.83、1.43、10.98、0.10 HU。对于单能量扫描,随着管电压的降低,伪影逐步加重。对于双能量扫描单色谱图像,管电流越低伪影越严重;光子能量越低伪影越严重。经过金属伪影削减算法处理的单能量图像,金属伪影明显减轻。结论:与单能量扫描相比,双能量CT扫描高光子能量单色谱图像联合MAR算法能有效抑制股骨柄假体金属伪影。光子能量越高,金属伪影越小。
Objective:To quantify the reduction of metal artefacts of hip prosthesis using virtual monochromatic spectral(VMS) images of dual-energy CT(DECT) scan combined with metal artifact reduction(MAR) algorithm.Methods:The water-filled phantom with hip prosthesis was scanned using a single-source single-layer detector dual-energy CT scanner.Scans were carried out using single-energy CT(SECT) mode at different tube potentials(80,100,120,140 kVp),and using DECT mode with different tube currents(200,484 mA).VMS images at 40,90 and 140 keV with and without MAR algorithm were reconstructed from DECT scans.16 sets of images were evaluated in terms of artifact area(AA) and artifact index(AI) and compared.Results:The artifact area and artifact index of 16 sets of images(140 kVp,120 kVp,100 kVp,80 kVp,40 keV 485 mA,40 keV 485 mA MAR,90 keV 485 mA,90 keV 485 mA MAR,140 keV 485 mA,140 keV 485 mA MAR,40 keV 200 mA,40 keV 200 mA MAR,90 keV 200 mA,90 keV 200 mA MAR,140 keV 200 mA,140 keV 200 mA MAR) were 787,1088,1499,2133,5664,650,665,172,279,157,7603,886,803,238,423,172 mm~2,and 22.75,33.65,58.58,92.55,195.18,3.53,23.38,0.35,7.88,0.05,230.28,4.95,24.83,1.43,10.98,0.10 HU,respectively.For SECT,higher tube potential generated less metal artifacts.For VMS images from DECT,higher photon energy and higher tube current produced less metal artifacts.VMS images with MAR algorithm significantly decreased both metal artifact area and artifact index.Conclusion:VMS images reconstructed with MAR algorithm provided improved image quality by reducing metal artifacts of hip prosthesis,especially with higher energy levels.
Objective:To quantify the reduction of metal artefacts of hip prosthesis using virtual monochromatic spectral(VMS) images of dual-energy CT(DECT) scan combined with metal artifact reduction(MAR) algorithm.Methods:The water-filled phantom with hip prosthesis was scanned using a single-source single-layer detector dual-energy CT scanner.Scans were carried out using single-energy CT(SECT) mode at different tube potentials(80,100,120,140 kVp),and using DECT mode with different tube currents(200,484 mA).VMS images at 40,90 and 140 keV with and without MAR algorithm were reconstructed from DECT scans.16 sets of images were evaluated in terms of artifact area(AA) and artifact index(AI) and compared.Results:The artifact area and artifact index of 16 sets of images(140 kVp,120 kVp,100 kVp,80 kVp,40 keV 485 mA,40 keV 485 mA MAR,90 keV 485 mA,90 keV 485 mA MAR,140 keV 485 mA,140 keV 485 mA MAR,40 keV 200 mA,40 keV 200 mA MAR,90 keV 200 mA,90 keV 200 mA MAR,140 keV 200 mA,140 keV 200 mA MAR) were 787,1088,1499,2133,5664,650,665,172,279,157,7603,886,803,238,423,172 mm~2,and 22.75,33.65,58.58,92.55,195.18,3.53,23.38,0.35,7.88,0.05,230.28,4.95,24.83,1.43,10.98,0.10 HU,respectively.For SECT,higher tube potential generated less metal artifacts.For VMS images from DECT,higher photon energy and higher tube current produced less metal artifacts.VMS images with MAR algorithm significantly decreased both metal artifact area and artifact index.Conclusion:VMS images reconstructed with MAR algorithm provided improved image quality by reducing metal artifacts of hip prosthesis,especially with higher energy levels.
引文
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[12] Takrouri HS,Alnassar MM,Amirabadi A,et al.Metal artifact reduction added value of rapid-kilovoltage-switching dual-energy CT in relation to single-energy CT in a piglet animal model[J].AJR,2015,205(3):W352-W359.
[13] Kidoh M,Utsunomiya D,Oda S,et al.CT venography after knee replacement surgery comparison of dual-energy CT-based monochromatic imaging and single-energy metal artifact reduction techniques on a 320-row CT scanner[J].Acta Radiol Open,2017,6(2):1-8.
[14] Filograna L,Magarelli N,Leone A,et al.Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies[J].Skeletal Radiol,2015,44(9):1287-1294.
[2] Jeong S,Kim SH,Hwang EJ,et al.Usefulness of a metal artifact reduction algorithm for orthopedic implants in abdominal CT phantom and clinical study results[J].AJR,2015,204(2):307-317.
[3] 侯凯,吕鹏,唐启瑛,等.320排CT单能量去金属伪影技术用于内脏动脉瘤弹簧圈栓塞术后随访的应用研究[J].放射学实践,2018,33(4):423-427.
[4] 赵艳娥,宁辉,郑玲,等.双能量CT虚拟单能谱成像技术在脑动脉瘤夹闭术后评估中的应用[J].放射学实践,2014,29(9):988-992.
[5] 董鑫,吕国士,刘伟,等.能谱CT的MONO成像联合MARS技术在颅内弹簧圈植入物伪影的应用研究[J].临床放射学杂志,2016,35(5):794-798.
[6] Yasuda M,Yoshikawa K,Kato K,et al.Validation of a metal artifact reduction algorithm using 1D linear interpolation for cone beam ct after endovascular coiling therapy for cerebral aneurysms[J].Neuroradiol J,2014,27(6):742-754.
[7] 毕正宏,王鸣鹏,毛定彪,等.骨折金属固定术后能谱CT图像质量的初步研究[J].中国医学计算机成像杂志,2013,19(1):75-78.
[8] Guggenberger R,Winklhofer S,Osterhoff G,et al.Metallic artefact reduction with monoenergetic dual-energy CT systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels[J].Eur Radiol,2012,22(11):2357-2364.
[9] Pessis E,Sverzut JM,Campagna R,et al.Reduction of metal artifact with dual-energy CT virtual monospectral imaging with fast kilovoltage switching and metal artifact reduction software[J].Semin Musculoskelet Radiol,2015,19(5):446-455.
[10] Wellenberg RH,Boomsma MF,van Osch JA,et al.Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses[J].Eur J Radiol,2017,88(3):61-70.
[11] Han SC,Chung YE,Lee YH,et al.Metal artifact reduction software used with abdominopelvic dual-energy CT of patients with metal hip prostheses assessment of image quality and clinical feasibility[J].AJR,2014,203(4):788-795.
[12] Takrouri HS,Alnassar MM,Amirabadi A,et al.Metal artifact reduction added value of rapid-kilovoltage-switching dual-energy CT in relation to single-energy CT in a piglet animal model[J].AJR,2015,205(3):W352-W359.
[13] Kidoh M,Utsunomiya D,Oda S,et al.CT venography after knee replacement surgery comparison of dual-energy CT-based monochromatic imaging and single-energy metal artifact reduction techniques on a 320-row CT scanner[J].Acta Radiol Open,2017,6(2):1-8.
[14] Filograna L,Magarelli N,Leone A,et al.Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies[J].Skeletal Radiol,2015,44(9):1287-1294.