肾上腺肿物MR反相位成像检查的初步研究

Application of MR Opposed-phase Imaging in the Examination of Adrenal Masses: A Preliminary Study

目的：报告肾上腺肿物MR反相位成像检查的方法，比较不同的分析方法所得结果，并探讨此成像方法的诊断价值。材料与方法：使用增强前屏气快速多层面破坏性梯度回波序列（FMICR）对24例肾上腺肿物（嗜铬细胞瘤10例，功能性腺癌9例，肾上腺囊肿2例，髓样脂肪瘤1例，单侧和双例肾上腺转移瘤各1例）分别进行同相位（IP）和反相位（OP）检查，并分别采用目测法和数值测量法判断与IP相比，肿物信号强度（SI）在OP上是否下降。结果：25个肿物分为痛内脂肪组（包括腺癌和髓样脂肪瘤）和非瘤内脂肪组（包括嗜铬细胞瘤、转移瘤和肾上腺囊肿）。目测法判断9个肿物出现信号下降，均属瘤内脂肪组（敏感性90％，特异性为100％）;数值测量法SI指数（代表肿物SI在OP上降低的百分比）在瘤内脂肪组和非瘤内脂肪组之间有显著性差异；以SI指数下降20％为阳性阈值，瘤内脂肪组均出现信号下降（敏感性100％，特异性100％）；数值测量法肝脾校正前、后比较无显著性差异。结论：OP检查能敏感地判断肾上腺肿物内是否富含脂肪，对肾上腺腺瘤和非腺癌性肿物的鉴别有很高价值。

Objective= To introduce MR opposed-phase imaging method, to compare the results with different algorithms and to evaluate this technique in the diagnosing of adrenal masses. Materials and Methods: Precontrast in-phase (IP) and opposed-phase (OP) MR scans were perfomed in 24 patients with pheochromocytoma (n = 10), hyper-functional adenoma (n = 9), cyare (n = 2), myelolipoma (n = 1 ) or metastatic tumor (1 unilateral and 1 bilateral), using breath-hald fast multiplanar spoiled gradient-recalled ecbo sequences. The results were analyzed by both visual and quantitative assessment, and whether the signal intensity (SI) wn decreased or not on OP images was determined by comparing OP with IP images. Results:The total 25 masses were divided into fat-containing group, including adm and myelolipoma, and non-fat-containing group, including pheochromocytoma, metastasis and cyst. Nine masses showing decreased SI on OP images could be detected by visual iuspection, and all the lesioas were fat-containing (seasihvity 90 %, specificity 100% ). A significant difference existed between the quantitatively estimated SI index of two groups, which represented the decreased percentage of SI on OP images. Taking 20% deerease in SI index as the upper limit, fat-containing group drted 100 % sensihvity and specificity. Mo remarkable difference was found between the indexes adjusted and non-adjusted by liver and spleen. Conclusion: OP imaging can detect fat component in adrinal masses with high sensihvity, and, therefore, is very useful in differentiating adenomas from non-adenomas of adrenal gland.