Department of Radiology G. B. Rossi Hospital, University of Verona, 37134 Verona, Italy.
AJR Am J Roentgenol. 2010 Jun;194(6):1484-91. doi: 10.2214/AJR.09.3636.
The purpose of this study was to retrospectively evaluate the accuracy of unenhanced attenuation and relative percentage wash-in ratio in early, that is, arterial and portal venous phase, biphasic CT in differentiating adrenal adenomas from metastatic lesions.
One hundred seven adrenal masses in 86 consecutively registered patients (45 men, 41 women; mean age, 56 years) were evaluated. Diagnosis was achieved with percutaneous biopsy (n = 6), surgery (n = 13), and at least 1 year of imaging follow-up (n = 88). Unenhanced, arterial phase, and portal phase scans were obtained. Diameter and absolute attenuation values in each phase of CT were measured in a region of interest covering one to two thirds of a lesion. Relative percentage wash-in ratio was calculated. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in differentiation of adenomas from metastatic lesions were calculated for unenhanced attenuation and for wash-in ratio. A value of p < 0.05 was considered significant.
The final diagnosis was metastasis in 51 cases and adenoma in 56 cases. A significant difference was found between benign and malignant lesions in regard to diameter (p = 0.001), unenhanced CT attenuation (p = 0.001), and relative percentage wash-in ratio from the arterial to the portal venous scan (p = 0.014). In the differentiation of benign from malignant lesions, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of unenhanced CT attenuation (at an 11-HU threshold) were 98%, 86%, 86%, 98%, and 92%, and those of relative percentage wash-in ratio from the arterial to the portal venous phase were 94%, 77%, 79%, 93%, and 85%.
Relative percentage wash-in ratio may help in differentiating adenoma from metastasis and in guiding the decision to perform CT directed at the adrenal glands when unenhanced CT is not available.
本研究旨在回顾性评估在双相 CT 的动脉期和门静脉期早期（即动脉期和门静脉期），不增强衰减和相对百分比增强比值在鉴别肾上腺腺瘤与转移瘤中的准确性。
评估了 86 例连续登记患者（45 例男性，41 例女性；平均年龄 56 岁）的 107 个肾上腺肿块。诊断方法为经皮活检（n=6）、手术（n=13）和至少 1 年的影像学随访（n=88）。进行了平扫、动脉期和门静脉期扫描。在一个或两个三分之二的病变区域，使用感兴趣区域测量各期 CT 的直径和绝对衰减值。计算相对百分比增强比值。计算了不增强衰减和增强比值在鉴别腺瘤和转移瘤方面的敏感性、特异性、阳性预测值、阴性预测值和准确性。p<0.05 被认为具有统计学意义。
最终诊断为 51 例转移瘤和 56 例腺瘤。良性和恶性病变之间在直径（p=0.001）、不增强 CT 衰减（p=0.001）和从动脉到门静脉扫描的相对百分比增强比值（p=0.014）方面有显著差异。在鉴别良性和恶性病变时，不增强 CT 衰减（在 11-HU 阈值下）的敏感性、特异性、阳性预测值、阴性预测值和准确性分别为 98%、86%、86%、98%和 92%，从动脉到门静脉期的相对百分比增强比值分别为 94%、77%、79%、93%和 85%。
相对百分比增强比值有助于鉴别腺瘤与转移瘤，并在无法进行平扫 CT 时指导对肾上腺进行 CT 引导的决策。
