股骨颈疝窝的磁共振弥散加权成像

Diffusion-weighted magnetic resonance imaging study on herniation pit of femoral neck

背景:目前利用磁共振弥散成像反映股骨颈疝窝的水分子弥散特征的研究尚少有报道。目的:利用磁共振表观弥散系数定量测定对股骨颈疝窝和正常股骨颈进行鉴别,探讨股骨颈疝窝的弥散系数值、影像学表现和发病机制。方法:收集18例经病理证实或具有典型影像学征象的股骨颈疝窝影像学患者的资料,全部患者均行X射线平片、CT、常规磁共振成像和弥散加权成像检查。依据CT和常规磁共振成像上异常表现,行股骨颈疝窝弥散系数测量,并与正常股骨颈弥散系数值进行比较。结果与结论:18例患者共20个病灶,均位于股骨头基底和股骨颈前外侧皮质下,形态呈圆形、卵圆形或分叶状。X射线平片上表现为伴清晰薄层硬化缘的透亮区,CT上表现为伴锐利的薄层硬化缘的骨质缺损区,磁共振成像上T1WI为低信号,T2WI为高信号。股骨颈疝窝的表观弥散系数值明显高于正常股骨颈。结果提示,弥散加权成像为股骨颈疝窝的诊断提供有价值的信息,证实股骨颈疝窝的弥散增加和弥散系数值升高。

BACKGROUND：At present,the report on the characteristics of water diffusion of femoral neck herniation pit by using magnetic resonance diffusion imaging is still rare.OBJECTIVE：To evaluate the femoral neck herniation pit and normal femoral neck by apparent diffusion coefficient（ADC） and to investigate the diffusion coefficient,imaging findings and pathogenesis of the femoral neck herniation pit.METHODS：The data of 18 cases of herniation pits proved by pathology or typical imaging manifestations were analyzed.All patients underwent conventional magnetic resonance imaging and diffusion-weighted imaging as well as CT and X-ray observation.The abnormal regions on the diffusion-weighted images were outlined by using the conventional magnetic resonance imaging or CT as guides,and the ADCs were calculated.The ADC differences between herniation pits and the femoral neck were compared.RESULTS AND CONCLUSION：Twenty herniation pits of the femoral neck were found in 18 cases.The lesions were round,oval or ＂8＂-shaped subcortical defects which were located in the anterior lateral base part of femoral head or the femoral neck.X-ray plain film showed a round radiolucency with a thin clear sclerotic rim.CT scans showed a well-defined lesion.Magnetic resonance imaging displayed low signal intensity on T1WI and high signal intensity on T2WI.The mean ADC was markedly greater in the herniation pits than that in the normal femoral neck.Diffusion-weighted imaging can provide valuable information for regarding the diffusion properties of herniation pit of the femoral neck,and markedly increased diffusion and ADC were identified in herniation pit of the femoral neck.