肿瘤廓清率在动态增强MRI检查中对肾上腺肿瘤的鉴别诊断价值

目的　探讨应用动态增强MRI检查技术 ,以肿瘤的廓清率为标准 ,再结合该时间点的信号增加比 ,对肾上腺腺瘤与非腺瘤进行鉴别诊断的临床价值。方法　 3 6例共 41个肾上腺肿瘤均先行常规SE序列T1 WI及T2 WI成像 ,再利用屏气快速多层面破坏性梯度回波序列 (fastmultiplanarspoiledgradient-echo ,FMPSPGR)行轴位扫描 ,先平扫 ,再以同样条件行MRI动态增强检查 ,观察病变的增强程度并分别测量肿瘤实质部分的信号值。分别比较腺瘤与非腺瘤的廓清率及信号增加比 ,明确其鉴别诊断价值。结果　延时 5min并以廓清率 2 2 %为阈值时 ,诊断腺瘤的敏感性 74% ,特异性 73 % ,准确性 73 % ;若将延时 5min时肿瘤的廓清率 (2 2 % )与信号增加比(<0 .48)相结合 ,则诊断腺瘤的敏感性、特异性、准确性明显提高 ,分别为 95 %、91%、93 %。结论　利用动态增强检查技术 ,以肿瘤的廓清率为标准 ,再结合该时间点的信号增加比 ,可在最短的时间内提高肾上腺腺瘤与非腺瘤的鉴别诊断水平

The Differential Diagnostic Value of Dynamic Contrast - Enhanced MRI in Adrenal Adenomas and Nonadenomas with the Washout Rate of Enhancement

Objective To explore the value of MRI dynamic contrast-enhanced in differentiating adrenal adenomas from nonadenomas with washout rate of enhancement and the increased SI ratio. Methods Thirty-six patients with 41 adrenal masses enrolled into this study. All these masses underwent conventional T 1WI and T 2WI sequence first, and then FMPSPGR sequence through the center of each mass. Precontrast and dynamic contrast-enhanced FMPSPGR scans were preformed after administration of contrast material of Gd-DTPA intravenously. The signal intensity(SI) of masses was measured on the screen by electronic cursor. The washout rate of enhancement and increased SI ratio were compared between adenomas and nonadenomas. The differentiating adrenal adenomas from nonadenomas were carried out based on combination of the washout rate and the increased SI ratio, meanwhile, the sensitivity and specificity of the diagnosis of adenomas were evaluated well.Results The sensitivity and specificity of the diagnosis of adenomas were 74% and 73%,and accuracy was 73% when the washout ratio was used as a indicator at 5 min. The sensitivity and specificity of the diagnosis of adenomas would be improved markedly when the combination of the washout ratio and the increased SI ratio was used as a indicator.The sensitivity and specificity of the diagnosis of adenomas were 95%, 91% respectively,and accuracy was 93%. Conclusion Using MRI dynamic contrast-enhanced based on combination of washout rate of enhancement and the increased SI ratio,the diagnosis and differentiating diagnosis of adrenal adenoma and nonadenoma can be improved.