伽玛刀治疗脉络膜黑色素瘤近期疗效的MRI观察

目的对比脉络膜黑色素瘤(choroidal melanoma)伽玛刀(gamma knife radiosurgery,GKS)治疗前后的MRI表现,探讨MRI对评估GKS近期治疗效果及预后的价值。方法回顾性分析27例脉络膜黑色素瘤患者GKR治疗前及治疗后3个月的MRI表现。结果 27例均为单眼单病灶,左眼15例,右眼12例。T1WI显示17例(63%)呈高信号,10例(37%)呈等信号;T2WI显示均为低信号;脂肪抑制T1WI均为明显高信号。3例瘤体信号显示欠均匀。15例行增强扫描,肉眼观察呈中等至明显强化,其中12例均匀强化,3例不均匀强化。8例可见视网膜脱离。1例伴有球外侵犯,眼睑软组织增厚,有明显强化。GKS后3个月17例瘤体不同程度缩小,10例无变化,未见体积增大者;肿瘤缩小程度分为4个等级:0%～25%者15例,26%～50%者4例,51%～75%者3例,76%～100%者5例,局部有效控制率为100%。1例伴视网膜脱离者脱离范围较治疗前缩小。伴有球外侵犯者眼睑软组织增厚及强化程度较前明显减轻。瘤体信号与治疗前相比无明显变化。结论 MRI不仅是脉络膜黑色素瘤不可替代的检查手段,而且在GKS治疗近期疗效评价及预后方面也具有重要参考价值。

Assessment the Recent Treatment Effect of GKR for Choroidal Melanoma Using MRI

Objective To evaluate the Gamma Knife Radiosurgery(GKS) treatment response and prognosis for choroidal melanoma using MRI.Methods MRI manifestations before and three months later after GKS treatment of 27 cases with choroidal melanoma were retrospectively analyzed.Results The choroidal melanoma involved one eye in all cases including 15 left eyes and 12 right eyes.17 cases(63%) showed hyperintense and 10 cases(37%) showed isointense on T1-weighted images.All cases showed hypointense with respect to the vitreous on T2-weighted images.On fat suppression sequence,all tumors appeared hyperintense.The signal of 3 tumors were heterogeneous.Moderate to intense enhancement was found in 15 cases.8 cases associated with secondary retinal detachment.Eyelid soft-tissue was involved in one patient.Three months later after GKS,the volume of tumors shrinked in 17 cases(63%) and the others did not change.The degree of shrinked volume were divided into 4 grades: tumors shrinked 0%-25% in 15 cases,26%-50% in 4,51%-75% in 3 and 76%-100% in 5 cases.The local control rate was 100%.The condition of retinal detachment and eyelid soft tissue involvement improved.The signal of all tumors did not change compared with that before GKS.Conclusion MRI was an important method in choroidal melanoma diagnosis and evaluating GKS treatment response for choroidal melanoma and prognosis.