Schweitzer M E, Falk A, Pathria M, Brahme S, Hodler J, Resnick D
Department of Radiology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA 19107.
AJR Am J Roentgenol. 1993 Apr;160(4):823-6. doi: 10.2214/ajr.160.4.8456672.
Synovial proliferation is difficult to detect on MR images when joint effusions are present. The objective of this study was to assess the efficacy of MR changes in intracapsular fat pads (prefemoral, quadriceps, Hoffa's) as a sign of synovial proliferation in patients with knee effusions.
MR images were obtained in 70 patients with knee effusions. An effusion was considered present if the suprapatellar bursa was distended 1 cm in anterior to posterior diameter on T2-weighted sagittal images. The experimental group consisted of 32 patients with proliferative effusions (effusions associated with synovial proliferation) diagnosed on the basis of histologic or microbiologic data or strict rheumatologic criteria. This group comprised 11 patients with pigmented villonodular synovitis, six with rheumatoid arthritis, one with psoriatic arthritis, three with hemosideric arthritis, and 11 with septic arthritis. The control group comprised 38 subjects with knee effusions who had no arthroscopic evidence of synovial proliferation. After determining the MR criteria of proliferative effusion, two observers who had no knowledge of these cases evaluated abnormalities of the intracapsular fat pads seen on sagittal intermediate-weighted midline MR images.
Characteristic changes in the fat pads were noted on MR images in patients with proliferative synovial effusions. Scalloping or truncation of the prefemoral fat pad was 77% sensitive and 95% specific as a predictor of proliferative effusion. Defects and displacement of Hoffa's fat pad had a sensitivity of 57% and a specificity of 99%, and nonvisualization or irregular margins of the quadriceps fat pad had a sensitivity of 61% and a specificity of 100%.
Characteristic changes in intracapsular fat pads seen on MR images of patients with proliferative effusions can help distinguish these patients from those with effusions without synovial proliferation.
当存在关节积液时，滑膜增生在磁共振成像（MR）上难以检测到。本研究的目的是评估关节内脂肪垫（股前、股四头肌、霍法氏）的MR改变作为膝关节积液患者滑膜增生征象的有效性。
对70例膝关节积液患者进行了MR成像检查。如果在T2加权矢状位图像上髌上囊前后径扩张1 cm，则认为存在积液。实验组由32例根据组织学或微生物学数据或严格的风湿病学标准诊断为增生性积液（与滑膜增生相关的积液）的患者组成。该组包括11例色素沉着绒毛结节性滑膜炎患者、6例类风湿性关节炎患者、1例银屑病关节炎患者、3例含铁血黄素性关节炎患者和11例化脓性关节炎患者。对照组由38例膝关节积液患者组成，这些患者没有关节镜下滑膜增生的证据。在确定增生性积液的MR标准后，两名对这些病例不知情的观察者评估了矢状位中等加权中线MR图像上所见的关节内脂肪垫异常。
增生性滑膜积液患者的MR图像上可见脂肪垫的特征性改变。股前脂肪垫的扇贝样或截断样改变作为增生性积液的预测指标，敏感性为77%，特异性为95%。霍法氏脂肪垫的缺损和移位敏感性为57% , 特异性为99%，股四头肌脂肪垫不可见或边缘不规则敏感性为61%，特异性为100%。
增生性积液患者的MR图像上所见的关节内脂肪垫特征性改变有助于将这些患者与无滑膜增生的积液患者区分开来。
