黄韧带肥厚的磁共振诊断

笔者对37例经手术与病理证实的黄韧带肥厚(HLF)之临床与磁共振表现及离体标本之光镜与电镜所见进行了分析。认为磁共振对HLF的诊断价值是:(1)可多方位显示HLF的位置、形态与厚度,对HLF在椎管内折曲情况及脊神经根管内神经根受卡压程度的判定优于其它影象检查。(2)可大范围、富有连续性地观察黄韧带周围的其它组织,有利于发现HLF之并存症,对多部位的HLF及多种病因引起之椎管狭窄症的诊断有重要价值。(3)对脂肪组织的显示甚为灵敏,有助于观察硬膜外脂肪的形态改变,可较精确测量硬膜囊矢状径、借助于硬膜囊受压百分比的测定可提示脊髓受压的程度。(4)可观察脊髓充血、水肿及变性引起之MR信号改变。 本组病例诊断中之假阴性与假阳性率为7％,文中探讨了降低假阴性与假阳性率的方法。 HLF的病理改变主要是弹力纤维的萎缩、断裂、纤维化及脂肪浸润与钙化,本组病例显示弹力纤维的钙化具有由外向内发展的方向性与规律性,此点在文献中尚未见报道。

MRI Diagnosis of the Hypertrophy of Ligamentum Flavum.

37 cases with hypertrophy of ligamentum flavum (HLF) proved by operation were reported. The results of MRI, optical and electron microscope were analyzed combining with clinical manifestation. Its histopathological characteristics were atrophy and fragmentation of the elastic fibers, proliferation and calcification of the collagen fibers, lipoidosis. The diagnostic value of MRI for HLF were: (1) Ligamentum flavum could be showed clearly and completely because of the natural contrastion anterior with fat and posterior with bone on MRI. (2) With better showing of ligamentum flavum and its peripheral structures, MRI was helpful to find jumpingly multi - section HLF and other sources of spinal stenosis. (3) It had high diagnostic rate for the lateral HLF. (4) MRI was very useful for the decision of the surgical incision by measurement of the compression percentage of dural sac. (5)The diformity, displacement of spinal sac and the abnormal signal intensity of spinal cord degeneration could be demonstrated. According to medical history, complication and histological chracteristics, the author concluded that the main causes of HLF were injury and degeneration of the ligamentrum flavum. It was discussed preliminarily why HLF would still show middle signal intensity.