BACKGROUND Surgeon's intraoperative estimation of meningioma extent of resection (Simpson Grade, SG) is widely used as a prognostic factor for recurrence. However, the validity of SG is still a matter of debate. In preoperative imaging, 68Ga-DOTATATE/PET-CT has been shown to detect meningioma tissue even more sensitively than magnetic resonance imaging (MRI). OBJECTIVE To evaluate the Simpson grading within the framework of modern postoperative imaging techniques (MRI; PET-CT). METHODS At first, patients with WHO grade I meningioma, surgical resection, and postoperative 68Ga-DOTATATE/PET-CT within 6 mo after surgery were retrospectively analyzed. Second, an analogous prospective cohort of patients with WHO grade I meningioma was investigated by comparing SG after meningioma removal with postoperative MRI and 68Ga-DOTATATE/PET-CT within 6 mo after surgery. RESULTS A total of 37 patients were retrospectively analyzed. In total, 5/8 patients with SG-I and II resections showed tumor remnants according to postoperative PET-CT (SG 62.5% false negative). In the prospective cohort of 52 tumors, PET-CT displayed tracer uptake in 15/37 SG-I or II resections indicating unexpected tumor remnants (SG 40.5% false negative). MRI was false negative in 7 of these 15 cases (MRI 18.9% false negative) (P = .037). Discordant results according to PET-CT were more often found in convexity (40%) and falcine (46.7%) meningiomas than in skull base meningiomas (18.2%). CONCLUSION Intraoperative Simpson grading is at risk to underestimate tumor remnants, predominantly in grade I and II resections. Postoperative PET-CT improves detection rates compared to MRI. Prognostic impact of postoperative meningioma remnants according to PET-CT needs to be investigated prospectively.

中文翻译：

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重新审视 Simpson 等级——脑膜瘤切除范围的术中估计与术后生长抑素受体正电子发射断层扫描/计算机断层扫描和磁共振成像

背景外科医生术中对脑膜瘤切除范围（Simpson Grade，SG）的估计被广泛用作复发的预后因素。但是，SG 的有效性仍然存在争议。在术前成像中，68Ga-DOTATATE/PET-CT 已被证明比磁共振成像 (MRI) 更灵敏地检测脑膜瘤组织。目的 在现代术后成像技术（MRI；PET-CT）的框架内评估 Simpson 分级。方法首先回顾性分析WHO I级脑膜瘤、手术切除、术后6个月内68Ga-DOTATATE/PET-CT的患者。第二，通过比较脑膜瘤切除后的 SG 与术后 6 个月内的 MRI 和 68Ga-DOTATATE/PET-CT，研究了一个类似的 WHO I 级脑膜瘤患者的前瞻性队列。结果 共对 37 名患者进行了回顾性分析。总共有 5/8 的 SG-I 和 II 切除患者根据术后 PET-CT 显示肿瘤残留（SG 62.5% 假阴性）。在 52 个肿瘤的前瞻性队列中，PET-CT 在 15/37 SG-I 或 II 切除中显示示踪剂摄取，表明存在意外的肿瘤残留物（SG 40.5% 假阴性）。在这 15 例中，有 7 例的 MRI 为假阴性（MRI 为 18.9% 假阴性）（P = .037）。与颅底脑膜瘤 (18.2%) 相比，PET-CT 结果不一致更常见于凸面 (40%) 和镰刀状 (46.7%) 脑膜瘤。结论 术中 Simpson 分级存在低估肿瘤残留的风险，主要是在 I 级和 II 级切除中。与 MRI 相比，术后 PET-CT 提高了检出率。根据 PET-CT，术后脑膜瘤残留对预后的影响需要前瞻性研究。