平扫CT值在常见肾上腺肿瘤鉴别诊断中的应用价值

目的:评价平扫CT值在肾上腺常见肿瘤诊断中的应用价值,并结合肿瘤大小优化选择肾上腺腺瘤与非腺瘤的鉴别阈值。方法:回顾性分析经手术及病理证实的肾上腺肿瘤209例(221个病灶),其中腺瘤137个,非腺瘤84个,分别测量肿瘤的大小及平扫CT值并计算不同CT值阚值鉴别腺瘤与非腺瘤的敏感度、特异度、准确度、阳性预测值及阴性预测值。结果:137个腺瘤平扫CT值-12～59(13.19±12.84)HU,直径0.3～7.3cm,其中包括88个无功能性腺瘤,平扫CT值-12～59(15.04±13.01)HU;醛固酮腺瘤43个,平扫CT值-8～42(10.19±12.26)HU;皮质醇腺瘤6个,平扫CT值-4.6～18(7.58±10.16)HU。84个非腺瘤平扫CT值15～69(38.33±10.08)HU,直径1.5～11.6cm,包括:嗜铬细胞瘤43个,平扫CT值15～69(38.67±11.05)HU;节细胞神经瘤5个,平扫CT值18～39(29.60±8.65)HU;皮质癌28个,平扫CT值26～58(38.96±8.84)HU;转移癌8个,平扫CT值28～54(39.75±8.24)HU;腺瘤和非腺瘤的平均平扫CT值差异有显著性意义(t=-15.281,P=0.000)。使用CT值25HU且肿瘤大小≤4cm作为鉴别腺瘤与非腺瘤的阈值时诊断腺瘤的敏感度73.7%,特异度100%,准确度83.7%,阳性预测值100%,阴性预测值70%。结论:平扫CT值在肾上腺腺瘤与非腺瘤的鉴别诊断上有重要价值,以平扫CT值≤25且肿瘤大小≤4cm作为腺瘤的诊断标准是比较合适的,特异度高,敏感度及准确度均较高。但在进一步鉴别腺瘤及非腺瘤的组织类型及具体临床诊断中的作用有限,需结合临床其他检测手段及病理结果做出全面准确的判断。

The clinical application of the CT attenuation value in the differential diagnosis of common adrenal tumors

Objective:To evaluate application of the CT attenuation value in the diagnosis of common adrenal tumors and to define the proper threshold value for differentiating adrenal adenoma and non-adenoma according to CT attenuation value combined with tumor size.Method:A retrospective analysis of 209 cases of adrenal tumors(221 lesions),constituted by 137 adenomas and 84 non-adenomas which were confirmed by pathological results,was carried out.Tumor size and CT attenuation value were measured and the sensitivity,specificity,accuracy,positive predictive value and negative predictive value at different thresholds for differentiating the adrenal adenoma and non-adenoma were calculated respectively.Result:The mean CT attenuation value of 137 adenomas was 12-59(13.19 ± 12.84)HU,tumor size 0.3-7.3cm,including 88 no-function adenomas,the CT attenuation value-12-59(15.04 ± 13.01)HU;43 aldosterone adenomas,the CT attenuation value-8-42(10.19 ± 12.26)HU;6 cortisol adenomas,the CT attenuation value-4.6-18(7.58 ± 10.16)HU.The mean CT attenuation value of 84 non-adenomas was 15-69(38.33 ± 10.08)HU,tumor size 1.5-11.6 cm,including 43 pheochromocytomas,the CT attenuation value 15-69(38.67±11.05)HU;5 Ganglioneuroma tumors,the CT attenuation value 18-39(29.60 ± 8.65)HU;28 cortical carcinomas,the CT attenuation value 26-58(38.96 ± 8.84)HU;8 metastases,the CT attenuation value 28-54(39.75 ± 8.24)HU.There was significant difference in the mean CT attenuation value between adenomas and non adenoma(t=-15.281,P= 0.000).The sensitivity,specificity,accuracy,positive predictive value and negative predictive value for making the diagnosis of adenoma were 73.7%,100%,83.7%,100%,70%restectively according to the CT attenuation value was less than 25 HU and the tumor size less than 4 cm.Conclusion:The application of CT attenuation value is valuable for the differential diagnosis of adrenal tumors and the threshold at the CT attenuation value ≤25 HU and the tumor size ≤4 cm is a proper criterion for the diagnosis of adenoma,at which the specificity,sensitivity and accuracy are all reliable.However,the value of the CT attenuation value is limited.The further identification of tissue type in adenoma or non-adenoma need to combine clinical and pathological results of other examinations to make a comprehensive and accurate judgments.