Department of Radiology, University of California Davis, 4860 Y Street, Suite 3100, Sacramento, CA, 95817, USA.
Radiologia Pediatrica - Ospedale dei Bambini, ASST Spedali Civili , Brescia, Italy.
Skeletal Radiol. 2020 Jun;49(6):1005-1014. doi: 10.1007/s00256-020-03372-5. Epub 2020 Jan 22.
The objectives of the study are (1) to distinguish lipoma (L) from atypical lipomatous tumor (ALT) using MRI qualitative features, (2) to assess the value of contrast enhancement, and (3) to evaluate the reproducibility and confidence level of radiological readings.
Patients with pathologically proven L or ALT, who underwent MRI within 3 months from surgical excision were included in this retrospective multicenter international study. Two radiologists independently reviewed MRI centrally. Impressions were recorded as L or ALT. A third radiologist was consulted for discordant readings. The two radiologists re-read all non-contrast sequences; impression was recorded; then post-contrast images were reviewed and any changes were recorded.
A total of 246 patients (135 females; median age, 59 years) were included. ALT was histopathologically confirmed in 70/246 patients. In multivariable analysis, in addition to the lesion size, deep location, proximal lower limb lesions, demonstrating incomplete fat suppression, or increased architectural complexity were the independent predictive features of ALT; but not the contrast enhancement. Post-contrast MRI changed the impression in a total of 5 studies (3 for R1 and 4 for R2; 2 studies are common); all of them were incorrectly changed from Ls to ALTs. Overall, inter-reader kappa agreement was 0.42 (95% CI 0.39-0.56). Discordance between the two readers was statistically significant for both pathologically proven L (p < 0.001) and ALT (p = 0.003).
Most qualitative MR imaging features can help distinguish ALTs from BLs. However, contrast enhancement may be limited and occasionally misleading. Substantial discordance on MRI readings exists between radiologists with a relatively high false positive and negative rates.
本研究的目的是（1）通过 MRI 定性特征区分脂肪瘤（L）和非典型脂肪肉瘤（ALT），（2）评估对比增强的价值，以及（3）评估放射学读数的可重复性和置信度水平。
本回顾性多中心国际研究纳入了在手术切除后 3 个月内接受 MRI 检查且经病理证实为 L 或 ALT 的患者。两名放射科医生在中心独立阅片。印象记录为 L 或 ALT。对于不一致的读片，咨询第三位放射科医生。两名放射科医生重新阅读所有非对比序列的影像；记录印象；然后回顾增强后图像，并记录任何变化。
共纳入 246 名患者（135 名女性；中位年龄 59 岁）。246 名患者中有 70 名经病理证实为 ALT。多变量分析显示，除了病变大小、深部位置、下肢近端病变、不完全脂肪抑制、或结构复杂性增加外，ALT 的独立预测特征还包括病变位置、深度、病变位于下肢近端、影像不完全抑脂、结构复杂，而不是对比增强。增强 MRI 改变了总共 5 个研究的印象（R1 为 3 个，R2 为 4 个；有 2 个研究的印象改变是共同的）；全部是从 L 改为 ALT，然而改变是错误的。总的来说，两位阅片者之间的读者间kappa 一致性为 0.42（95%CI 0.39-0.56）。两位读者对病理证实的 L（p<0.001）和 ALT（p=0.003）的读片意见均存在统计学差异。
大多数定性 MRI 特征有助于区分 ALT 和 BL。然而，对比增强可能有限且偶尔具有误导性。放射科医生之间存在明显的 MRI 读片意见不一致，假阳性和假阴性率较高。
