Hospital for Special Surgery, New York, New York, USA.
Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
J Orthop Res. 2023 Jun;41(6):1299-1309. doi: 10.1002/jor.25472. Epub 2022 Nov 6.
The infrapatellar fat pad (IPFP) has been implicated as a source of postoperative knee pain. Imaging the IPFP is challenging in patients with total knee arthroplasty (TKA) due to metallic susceptibility artifact. Multi-Acquisition Variable-Resonance Image Combination (MAVRIC)-based T2 Mapping has been developed to mitigate this artifact and can generate quantitative T2 data. Objectives of this study were to (1) measure T2 values of the IPFP in patients with TKAs using a MAVRIC based T2 mapping technique and (2) determine if IPFP T2 values are related to the degree of fat pad scarring or clinical magnetic resonance imaging (MRI) findings. Twenty-eight subjects (10 males, 18 females, Age: 66 + 7.2 years [Mean ± standard deviations]) undergoing clinical MRIs were sequentially recruited. Morphological imaging and quantitative T2 mapping sequences were performed on a clinical 1.5 T scanner. The morphologic images were graded for the presence and severity of fat pad scarring and clinical outcomes. T2 values were calculated in the total fat pad volume, a normal regions of interest (ROI), and an abnormal ROI. T2 values were shortened in the total IPFP volume (p = 0.001) and within abnormal regions (p = 0.003) in subjects with more severe IPFP scarring. The difference between T2 values in normal-abnormal regions was greater in subjects with severe versus no scarring (+1426.1%, p = 0.008). T2 values were elevated in patients with MRI findings of osteolysis (+32.3%, p = 0.02). These findings indicate that MAVRIC-based T2 Mapping may be used as a quantitative biomarker of postoperative IPFP scarring in individuals following TKA.
髌下脂肪垫（IPFP）已被认为是术后膝关节疼痛的来源。由于金属敏感性伪影，在全膝关节置换术（TKA）患者中对 IPFP 进行成像具有挑战性。多采集可变共振图像组合（MAVRIC）基于 T2 映射技术已被开发出来以减轻这种伪影并可以生成定量 T2 数据。本研究的目的是：（1）使用基于 MAVRIC 的 T2 映射技术测量 TKA 患者的 IPFP 的 T2 值，以及（2）确定 IPFP T2 值是否与脂肪垫疤痕的程度或临床磁共振成像（MRI）发现相关。连续招募了 28 名接受临床 MRI 检查的受试者（10 名男性，18 名女性，年龄：66 + 7.2 岁[均值 ± 标准差]）。在临床 1.5T 扫描仪上进行形态学成像和定量 T2 映射序列。对形态图像进行脂肪垫疤痕的存在和严重程度以及临床结果进行分级。在总脂肪垫体积、正常感兴趣区（ROI）和异常 ROI 中计算 T2 值。在脂肪垫疤痕更严重的受试者中，总 IPFP 体积（p = 0.001）和异常区域内的 T2 值缩短（p = 0.003）。在严重与无疤痕的受试者中，正常-异常区域之间的 T2 值差异更大（+1426.1%，p = 0.008）。患有 MRI 骨溶解发现的患者 T2 值升高（+32.3%，p = 0.02）。这些发现表明，MAVRIC 基于 T2 映射技术可作为 TKA 后个体术后 IPFP 疤痕的定量生物标志物。
