齿突游离小骨MSCT和MRI表现特点和临床诊断(附15例报道)

The MSCT and MRI features and diagnosis of Os Odontoideum: A case series of 15 patients

目的游离齿突小骨(os odontoideum,OsO)少见,常常伴有环椎(C1)枢椎(C2)不稳、椎管狭窄、脊髓变性等。现回顾分析一组OsO的多层螺旋CT(MSCT)和磁共振成像MRI表现特点,便于提高对此病的早期诊断。方法分析我们医院2010年~2014年间搜集的15例OsO,全部病例行MSCT及三维重组和MRI。结果 MSCT及三维重组能显示OsO及骨皮质100%,小骨移位为93.3%,C2齿突基底部移位100%,椎管骨性狭窄100%,C1/2关节不稳100%,脊髓受压变细93.3%。MRI显示游离齿突小骨及骨皮质为80.0%,小骨移位为93.3%,C1/2关节不稳为100%,C2齿突基底部移为100%,脊髓受压为93.3%。MSCT及三维重组MSCT显示脊髓变性为0.0%,MRI则显示脊髓变性为100%,两者结果差别有显著性(P<0.00),二者上述其他结果则差别无显著性。结论 MSCT和/或MRI能够诊断OsO,如在C2齿突之上发现有完整骨皮质的游离小骨。本组结果表明MSCT主要优点是显示小骨骨皮质好、显示微小小骨优于MRI,而MRI则显示脊髓受压变性明显优于MSCT,因此两者结合在诊断OsO、指导选择治疗方法上可互为补充。

Objective Osodontoideum（ OsO） is rare,often accompanying with atlanto-axial instability（ C1/C2）,cervical spinal canal stenosis and spinal cord degeneration,etc. MSCT and MR imaging findings of OsO were reviewed retrospectively,so that to improve the diagnosis of OsO. Methods 15 cases of OsO were collected and reviewed during 2010 to 2014 year in our hospitals. MSCT and MRI of cervical spine were performed to verify OsO. Results MSCT revealed that the ossicles were found in 100%,the dissociating ossicles in 93. 3%,C2 odontoid base displacement in 100%,spinal canal stenosis in 100%,C1/C2 instability in 100%,spinal cord compression in 93. 3%. MRI revealed that the ossicles were found in 80. 0%,the malposition ossicles in 80. 0%. C2 odontoid base displacement and spinal canal stenosis were 100%,C1/2 instability was 100%,the compression of the spinal cord was 93. 3%,myelopathy was 93. 3%. There was significant difference betwen MSCT and MRI to reveal the spinal cord degenerative myelopathy（ P〈0. 00）,there were no significant differences（ P〉0. 00） among the other results of MSCT and MRI. Conclusion MSCT and/or MRI can diagnose OsO if they find out a dissociating ossicle with surrounding complete bone cortex above C2 odontoid base. The results reveal that MSCT be better than MRI to show the bone cortex of the ossicles and the very tiny ossicles in this series,and MRI is obviously better than MSCT to show the myelopathy.