CT直方图分析对肾上腺乏脂性腺瘤的定性诊断价值

摘要

目的:探讨CT直方图分析的负值像素百分比对平扫CT值＞10 HU的肾上腺乏脂性腺瘤与非腺瘤的鉴别诊断价值.方法:回顾性分析经手术病理证实或随访一年以上的192个肾上腺肿瘤,其中97个平扫CT值≤10 HU富脂性腺瘤,47个平扫CT值＞10 HU乏脂性腺瘤,48个非腺瘤.测量富脂性腺瘤、乏脂性腺瘤与非腺瘤平扫CT值和负值像素百分比并比较其间差异,利用受试者操作曲线选择鉴别乏脂性腺瘤与非腺瘤的最合适阈值.结果:乏脂性腺瘤平扫CT值(24.90±9.58) HU与非腺瘤平扫CT值(35.48±8.37) HU无显著差异(P＞0.05),乏脂性腺瘤的负值像素百分比(19.49±10.31)％高于非腺瘤(1.89±2.23)％,二者具有显著性差异(P=0.000).31个平扫CT值位于10～30 HU的乏脂性腺瘤的负值像素百分比全部大于10％,而15个平扫CT值＞30 HU的乏脂性腺瘤只有8个(53.33％)的负值百分比大于10％.当肾上腺肿瘤的负值像素百分比取10％时,诊断乏脂性腺瘤的敏感性为80.9％,特异性为97.9％.结论:CT直方图分析可提高平扫CT对乏脂性腺瘤的诊断准确性,对平扫CT值为10～30 HU之间的乏脂性腺瘤的诊断效能最高.%Objective: To evaluate the diagnostic value of CT histogram analysis in the characterization of lipid-poor a-drenal adenomas. Methods: A total of 192 adrenal masses in 184 patients were confirmed either by histopathology or by following up for at least 12 months, including 97 lipid-rich adenomas, 47 lipid-poor adenomas and 48 nonadenomas. Unen-hanced CT attenuation was measured on every mass and the percentage of negative pixel was calculated by CT histogram analysis. Receiver operating characteristic curve analysis was performed to choose the optimal cut-off value to differentiate between lipid-poor adenomas and nonadenomas. Result: There was no statistical difference of unenhanced CT attenuation between lipid-poor adenomas (mean (24.90±9.58) HU) and nonadenomas (35.48±8.37) HU(P>0.05), however, lipid-poor adenomas (n=47,mean (19.49±10.31)%) showed significantly higher(t=11.55, P=0.000) negative value percentage than nonadenomas (n=48, mean (1.89±2.23)%). All 31 lipid-poor adenomas with CT attenuations between 10 HU to 30 HU had a negative pixel percentage over 10%. Only 8 of 15 lipid-poor adenomas with CT attenuations above 30 HU had a negative pixel percentage above 10%. At a cut-off value of 10%, the sensitivity and specificity of calculated negative value percentage to diagnose lipid-poor adenomas were 80.9% and 97.9% respectively. Conclusion: CT histogram analysis can help to improve diagnostic accuracy of CT densitometry in characterization of lipid-poor adenomas, especially lipid-poor adenomas with unenhanced CT attenuations between 10 HU to 30 HU.