膝关节树枝状脂肪瘤的MRI征象分析及其与骨性关节炎关系的探讨

Lipoma Arborescens of the Knee Joint: Analysis of MRI Features and Its Relationship with Osteoarthritis

目的研究膝关节树枝状脂肪瘤(LA)的典型MRI表现以及伴随病变,并探讨其与骨性关节炎的关系。方法回顾性分析13例LA患者的膝关节(n=15)MRI图像,其中2个膝关节为病理证实,其余13个膝关节有典型MRI表现诊断。所有患者均行MR平扫,其中1例行增强扫描。结果全部病例均累及髌上囊,其中3例同时蔓延至关节周围滑膜,MR表现为滑膜呈"树叶"状、"树枝"状、"绒毛"状增厚,T1WI序列上为高信号、T2WI序列上为稍高信号,脂肪抑制序列上呈低信号,1例增强后滑膜呈明显强化。其中局灶结节型6.7%(1/15),弥漫型53.3%(8/15),混合型40.0%(6/15)。15个受累膝关节均伴关节积液;其中93.3%(14/15)伴骨性关节炎改变;40.0%(6/15)伴半月板损伤;26.7%(4/15)伴滑膜囊肿;20.0%(3/15)伴关节旁滑膜增厚;6.7%(1/15)伴滑膜骨软骨瘤病。结论膝关节LA在MRI上有特征性的形态信号改变,LA是引起骨性关节炎的因素之一。

Objective To investigate the typical MRI features of lipoma arborescens of the knee joint as well as its as- sociated disorders, and to discuss its relationship with osteoarthritis. Methods Thirteen patients with lipoma arborescens of the knee joint （ 15 diseased joints in total） were included in this study. The diagnosis was confirmed pathology in 2 joints and by typical MRI sings in 13 joints. Plain MRI scanning was performed in all patients, and additional contrast-enhanced scanning was employed in one case. Results The suprapatellar bursa was involved in all cases, and the para-articular synovium was also involoved in 3 cases. On MRI the articular synovium was characterized by ＂leaf shape＂, ＂dendritic＂ or ＂fluffy＂ thickening, which was manifested as high-intensity signal on Tl WI, slightly high-intensity signal on T2WI and low- intensity signal on short tau inversion recovery （STIR） pulse sequence images. Obvious enhancement of the synovium was observed in one case. The lesions could be divided into nodular type （n = 1, 6.7% ）, diffuse type （n =8, 53.3% ） and mixed type （ n = 6, 40.4% ）. Joint effusion was detected in all the 15 involved knee joints. Coexisting osteoarthritis was seen in 14 joints （93.3%）, meniscal injury in 6 joints （40.0%）, synovial cyst in 4 joints （26.7%）, para-articular sy- novium thickening in 3 joints （20%） and synovial osteochondromatosis in on joint （6.7%）. Conclusion The lipoma ar- borescens of knee joint has certain MRI signal features, and lipoma arborescens is one of the factors that cause osteoarthri- tis.