Objective Uterine leiomyomas are the most common benign uterine tumors. They are difficult to distinguish from their malignant counterparts—smooth muscle tumors of unknown malignant potential (STUMP) and leiomyosarcoma. The purpose of this study is to propose and validate the diagnostic accuracy of the MRI-based Oman-Canada Scoring System of Myometrial Masses (OCSSMM) to differentiate uterine leiomyomas from STUMP/leiomyosarcomas. Methods This is a retrospective study performed at two tertiary care centers. All patients with a pathology-proven uterine mass who underwent pre-operative pelvic MRI between January 2010 and January 2020 were included. Using a 1.5T MRI machine, sequences included were axial/coronal/sagittal T2 and T1 weighted imaging, axial diffusion weighted and apparent diffusion coefficient map, and axial or sagittal dynamic contrast-enhanced sequences. A scoring system was designed based on previously published worrisome MRI features for uterine leiomyosarcoma. Each feature was allocated a score from 0 to 2 according to the strength of association with malignancy. Subsequently, the MR images were blindly and independently reviewed by a fellowship-trained radiologist and a clinical fellow/senior resident. Each uterine mass was scored according to their imaging features. The scores were divided into five categories according to the sum of scores. Category III and above was considered positive for leiomyosarcoma/STUMP. Sensitivity, specificity, and positive and negative predictive values were calculated. Results A total of 244 women were included (age range 20–74 years, mean 40). Of these, 218 patients had benign leiomyoma, 13 had STUMP, and 13 had leiomyosarcoma. The sensitivity and specificity of the scoring system were 92.3% and 64.7%, respectively. The negative predictive value was 98.6%. No leiomyosarcoma was missed using this scoring system. The presence of non-cystic T2 hyperintensity or diffusion restriction in a uterine mass were the most sensitive signs of a leiomyosarcoma/STUMP. Conclusion The proposed multi-parametric MRI scoring system may be useful in differentiating benign uterine leiomyomas from leiomyosarcomas/STUMP. Data are available upon reasonable request. The data that support the findings of this study are available from the corresponding author, MAK, upon reasonable request.

中文翻译：

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验证基于 MRI 的评分系统区分良性子宫平滑肌瘤和平滑肌肉瘤的诊断准确性

目的子宫肌瘤是最常见的良性子宫肿瘤。它们很难与恶性潜能未知的平滑肌肿瘤（STUMP）和平滑肌肉瘤等恶性肿瘤区分开来。本研究的目的是提出并验证基于 MRI 的阿曼-加拿大子宫肌瘤评分系统 (OCSSMM) 区分子宫平滑肌瘤和 STUMP/平滑肌肉瘤的诊断准确性。方法 这是在两个三级护理中心进行的回顾性研究。所有在 2010 年 1 月至 2020 年 1 月期间接受术前盆腔 MRI 检查且经病理证实子宫肿块的患者均被纳入。使用 1.5T MRI 机器，包括的序列包括轴向/冠状/矢状 T2 和 T1 加权成像、轴向扩散加权和表观扩散系数图，以及轴向或矢状动态对比增强序列。评分系统是根据先前发表的子宫平滑肌肉瘤令人担忧的 MRI 特征设计的。根据与恶性肿瘤的关联强度，每个特征被分配从 0 到 2 的分数。随后，MR 图像由经过专科培训的放射科医生和临床研究员/高级住院医师进行盲目且独立的审查。根据每个子宫肿块的影像学特征对其进行评分。根据分数总和将分数分为五类。 III 类及以上被认为是平滑肌肉瘤/STUMP 阳性。计算敏感性、特异性以及阳性和阴性预测值。结果 总共纳入 244 名女性（年龄范围 20-74 岁，平均 40 岁）。其中，218 名患者患有良性平滑肌瘤，13 名患者患有 STUMP，13 名患者患有平滑肌肉瘤。评分系统的敏感性和特异性分别为92.3%和64.7%。阴性预测值为98.6%。使用该评分系统没有漏掉任何平滑肌肉瘤。子宫肿块中非囊性 T2 高信号或扩散受限的存在是平滑肌肉瘤/STUMP 的最敏感体征。结论所提出的多参数 MRI 评分系统可能有助于区分良性子宫平滑肌瘤和平滑肌肉瘤/STUMP。数据可根据合理要求提供。支持本研究结果的数据可根据合理要求从通讯作者 MAK 处获得。