MRI成像对肾上腺高密度肿瘤的应用价值

目的 探讨3T MRI化学位移成像(CSI)和扩散加权成像(DWI)对肾上腺高密度病变的应用价值.方法 回顾性分析48例患者61个CT值大于10HU的肾上腺高密度病变CSI及DWI成像,对肾上腺肿块同反相位的信号衰减值(SII)、肾上腺肿块-脾脏信号比(ASR)、表观扩散系数(ADC)值行散点图分析.采用SPSS 11.5进行统计学分析,并通过ROC曲线确定最佳诊断阈值、敏感性、特异性.结果 23个良性嗜铬细胞瘤,CSI信号衰减SII平均为3.73％;ASR平均为0.97,病变实性部分ADC值平均为(1.17×103)mm2/s.20个高密度腺瘤CSI示信号衰减SII平均为34.48％;ASR平均0.70,ADC值平均(1.08×103)mm2/s.13例恶性肿瘤CSI信号衰减SII为16.58％;ASR为0.96,ADC值为(0.88×10-3)mm2/s.良恶性病变间ADC值有明显统计学差异(P=0.002＜0.05),以ADC值小于0.99为标准,诊断高密度腺瘤的敏感性为70.8％,特异性为84.6％.高密度腺瘤的SII及ASR与其它高密度肿瘤有明显统计学差异,嗜铬细胞瘤的SII及ASR与其它高密度肿瘤有明显统计学差异.结论 CSI可有助于鉴别高密度腺瘤、嗜铬细胞瘤和恶性肿瘤;但无法鉴别嗜铬细胞瘤和恶性肿瘤.ADC值可有助于鉴别病变的良恶性.

The value of MR Imaging in assessment of hyperattenuating adrenal tumors

Objective To evaluate the application of MRI for hyperattenuating adrenal tumors on 3.0 T MR. Methods We restrospectively evaluated 61 cases of hyperattenuating adrenal tumors in 48 patients. Chemical shift imaging （CSI） and diffusionweighted imaging （DWI） were performed. Signal intensity index （SII）, adrenal-to spleen ratio （ASR） and apparent diffusion coefficient （ADC） were measured. A standard non-parametric test of two independent samples and receiver operating characteristic （ROC） analysis was used to analyse data. Results The mean SII, ASR and ADC value were listed as below： pheochromocytoma （n=23）, 3.73% 0.97, 1.17× 10 3mm2/s; adenoma （n=20）, 34.48%, 0.70, 1.08 × 10 3mm2/s; malignant tumors （n= 13）, 16.58% ; ASR 0.96, ADC 0.88 × 10 3mm2/s. There was significant difference between benign and malignant tumors for DWI. There were also significant differences between pheochromocytomas and other hyperattenuating tumors for SII and ASR. Conclusion CSI was valuable for differentiation of pheochromocytoma, hyperattenuating adenoma and malignant tumors, however it is not useful for differentiation of pheochromocytoma and oth er tumors. ADC values were valuable for differentiation of benign and malignant tumors.