多层螺旋CT后处理技术对飞行员腰椎峡部裂的诊断价值

Application of multi-slice CT postprocessing techniques in diagnosing lumbar spondylolysis of pilots

目的 探讨多层螺旋CT后处理技术对飞行员腰椎峡部裂（1umbar spondylolysis,LS）的诊断价值.方法 对385例改装体检的歼击机飞行员按年龄（23～28岁;29～34岁;35～40岁;41～46岁）及飞行时间（≤800 h;801～1600 h;1601～2400 h）分组;进行腰椎CT容积扫描.利用多层螺旋CT的多平面重建（multiplanar reconstruction,MPR）、最大密度投影（maximum intensity projection,MIP）和容积再现（volume rendering,VR）技术对图像进行后处理,多方位观察飞行员腰椎峡部裂情况,并比较MPR图像、MIP图像及VR图像.结果 ①飞行员不同年龄分布LS检出率无统计学差异;不同飞行时间LS检出率有统计学差异（x2=7.57,P＜0.05）,随着飞行时间延长LS检出率增高.②385例飞行员中共检出峡部裂16例（33处）,9例伴滑脱;其中双侧峡部裂13例（30处）,7例伴滑脱;单侧峡部裂3例（3处）,2例伴滑脱.MPR图像LS检出率为100%（33/33）,斜矢状（沿椎弓峡部走向）位及斜轴（平行于椎弓）位可清楚地显示峡部断裂情况,分别表现为＂猎狗项圈征＂和＂双关节征＂,正中矢状位可清楚地显示椎体滑脱情况.MIP图像LS检出率100%（33/33）,但对周边软组织显示不清楚.VR图像LS检出率为75.76%（25/33）,可立体观察峡部情况.结论 多层螺旋CT的后处理技术MPR、MIP、VR可以全方位地评价飞行员的腰椎峡部情况,其中斜矢状位及斜轴位的MPR图像可作为首选的重建方法.

Objective To evaluate the clinical application value of multi-slice CT （MSCT）postprocessing techniques in diagnosing lumbar spondylolysis （LS） of pilots. Methods Three hundred and eighty-five transformed pilots, who were grouped by age （23-28 yr, 29-34yr, 35-40 yr and 41-46 yr） and by flying hours （≤800 h, 801-1600 h and 1601-2400 h）, underwent volumetric MSCT scanning in physical examination. Then various postprocessing techniques including multiplanar reconstruction （MPR）, maximum intensity projection （MIP） and volume rendering （VR） were carried out at workstation for getting the LS information of pilots. The efficacy of MIP, MPR and VR were compared in diagnosing LS. Results There were 16 cases （at 33 places） of LS in 385 pilots,including 13 bilateral and 3 unilateral LS. Nine cases were accompanied with lumbar spondylolisthesis.The diagnosis rate by MPR images was 100% （33/33）, and in which ＂collar sign of Scottish hound＂,＂double articular process sign＂ and lumbar spondylolisthesis was respectively and clearly revealed on oblique sagittal plane, oblique axial plane and median sagittal plane. MIP images also screened out all LS cases but the viewing of soft tissue was not as good as MPR＇s. The diagnosis rate by VR imagines was 75. 76% （25/33） but it showed closely to the real anatomy structure of lumbar spine and stereoscopically displayed LS. Conclusions Postprocessing techniques, such as MPR, MIP and VR show good ability in diagnosing spondylolysis and its secondary abnormity. The oblique sagittal （along vertebral arch） and oblique axis （parallel to arch） MPR images are the first choice of reconstruction technique in diagnosing spondylolysis of pilots.