PURPOSE To assess the clinical and imaging features of IgG4-RKD for understanding and diagnosis of this disease. METHODS CT and MR images of 34 patients with IgG4-RKD were retrospectively analyzed by two radiologists in consensus. RESULTS The serum IgG4 level was found being increased in all patients. Renal involvement was bilateral (24/34, 70.6%) or unilateral (10/34,29.4%), multiple (29/34, 85.3%) or solitary (5/34, 14.7%). The lesions were wedge-shaped (21) or mass-like (4) in the renal parenchyma, whereas diffusely decreased renal density was noted in 2 patients. All lesions showed progressive contrast enhancement. The 4 mass-like lesions were misdiagnosed as renal malignancy. In 15 patients with follow-up imaging examinations, the number and size of renal lesions decreased after oral hormone treatment. The serum IgG4 levels were significantly decreased after therapy in all patients. CONCLUSION IgG4-RKD has various imaging appearances. Although the mass-like appearance mimics renal malignancy in some patients, progressive contrast enhancement in the lesion with elevated serum IgG4 suggests IgG4-RKD.

中文翻译：

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IgG4相关性肾脏疾病的临床和影像学特征。

目的评估IgG4-RKD的临床和影像学特征，以了解和诊断该疾病。方法由两位放射线医师对34例IgG4-RKD患者的CT和MR图像进行回顾性分析。结果发现所有患者的血清IgG4水平均升高。肾脏受累为双侧（24/34，70.6％）或单侧（10 / 34,29.4％），多发（29/34，85.3％）或单发（5/34，14.7％）。肾实质中的病变为楔形（21）或肿块状（4），而2例患者发现肾脏密度弥漫性降低。所有病变均显示进行性对比增强。这4例肿块样病变被误诊为肾恶性肿瘤。在15例接受了影像学检查的患者中，口服激素治疗后肾脏病变的数量和大小均减少了。治疗后所有患者的血清IgG4水平均显着降低。结论IgG4-RKD具有多种影像学表现。尽管在某些患者中肿块样外观模仿了肾恶性肿瘤，但随着血清IgG4升高，病灶中逐渐增强的造影剂提示IgG4-RKD。