PURPOSE It can be challenging to differentiate pseudoprogression from progression. We assessed the ability of dynamic contrast enhanced T1 MRI (DCE-MRI) perfusion to identify pseudoprogression in melanoma brain metastases. METHODS Patients with melanoma brain metastases who underwent immunotherapy and DCE-MRI were identified. Enhancing lesions ≥  5mm in diameter on DCE-MRI and that were new or increased in size between a week from beginning the treatment, and a month after completing the treatment were included in the analysis. The 90th percentiles of rVp and rKtrans and the presence or absence of hemorrhage were recorded. Histopathology served as the reference standard for pseudoprogression. If not available, pseudoprogression was defined as neurological and radiographic stability or improvement without any new treatment for ≥ 2 months. RESULTS Forty-four patients were identified; 64% received ipilimumab monotherapy for a median duration of 9 weeks (range, 1-138). Sixty-four lesions in 44 patients were included in the study. Of these, nine lesions in eight patients were determined to be pseudoprogression and seven lesions were previously irradiated. Forty-four progression lesions and eight pseudoprogression lesions were hemorrhagic. Median lesion volume for pseudoprogression and progression were not significantly different, at 2.3 cm3 and 3.2 cm3, respectively (p = 0.82). The rVp90 was smaller in pseudoprogression versus progression, at 2.2 and 5.3, respectively (p = 0.02), and remained significant after false discovery rate adjustment (p = 0.04). CONCLUSIONS Pseudoprogression exhibited significantly lower rVp90 on DCE-MRI compared with progression. This knowledge can be useful for managing growing lesions in patients with melanoma brain metastases who are receiving immunotherapy.

中文翻译：

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DCE-MRI灌注可预测通过免疫疗法治疗的转移性黑色素瘤的假性进展。

目的将伪进展与进展区分开来可能具有挑战性。我们评估了动态对比增强T1 MRI（DCE-MRI）灌注的能力，以识别黑色素瘤脑转移的假进展。方法确定接受免疫治疗和DCE-MRI检查的黑色素瘤脑转移患者。分析包括在开始治疗后一周至完成治疗后一个月之间，通过DCE-MRI增强的直径≥5mm的病灶，这些病灶是新的或增大的。记录了rVp和rKtrans的第90个百分位数以及是否存在出血。组织病理学是伪进展的参考标准。如果无法获得，则伪进展定义为神经学和影像学稳定或改善，且≥2个月未进行任何新治疗。结果确定了44例患者。64％的患者接受了ipilimumab单药治疗，中位疗程为9周（范围1-138）。本研究包括44例患者中的64个病变。其中，确定了八名患者中的九个病变为假进展，并且先前已辐照了七个病变。有44个进展性病变和8个假性进展性病变出血。假性进展和进展的中位病变体积无明显差异，分别为2.3 cm3和3.2 cm3（p = 0.82）。rVp90的伪进展与进展较小，分别为2.2和5.3（p = 0.02），并且在错误发现率调整后仍显着（p = 0.04）。结论与进展相比，伪进展在DCE-MRI上显示出明显更低的rVp90。