MR动态增强定量分析对腮腺良恶性肿瘤的鉴别

Differential diagnosis of parotid masses by dynamic contrast-enhanced MR

目的探讨3.0T MR动态增强扫描(DCE-MRI)定量分析对腮腺肿瘤鉴别诊断的价值。方法回顾性分析62例腮腺肿块病例的DCE-MRI检查,并经手术病理证实的87个腮腺肿块,分析各类病理类型肿块的定量参数值:转运常数(Ktrans值)、速率常数(Kep值)及血管外细胞外间隙容积分数(Ve值)。各组各定量参数值进行Kruskal-Wallis H检验,各参数值组内两两比较采用Mann-Whitney U检验,选择确定鉴别诊断的阈值并计算灵敏度、特异性。结果恶性腮腺肿瘤、腺淋巴瘤、混合瘤、其他良性肿瘤的Ktrans值、Kep值、Ve值组间差异有统计学意义(χ2值分别为8.627、45.409、50.938,P<0.01)。恶性肿瘤的Kep值较腺淋巴瘤低,恶性肿瘤的Ktrans值、Kep值均较混合瘤高。恶性肿瘤与腺淋巴瘤之间取截断点Kep=0.98min-1、Ve=0.351,诊断恶性肿瘤灵敏度均为75%,特异度为76.27%。恶性肿瘤与多形性腺瘤之间取截断点Ktrans=0.28 min-1,诊断恶性肿瘤灵敏度为67.85%,特异度为61.53%;取截断点Kep=0.69 min-1,诊断恶性肿瘤灵敏度为67.85%,特异度为73.07%。结论 DCE-MRI定量参数有助于腮腺良恶性肿块的鉴别诊断。

Objective To investigate the value of dynamic contrast-enhanced （DCE） MRI at 3.0T in differential diagnosis of parotid masses. Methods DCE-MRI was performed on 62 patients with 87 pathologically confirmed parotid masses. The quantitative parameters including Ktrans, Kep, and Ve of parotid masses were compared using Kruskal-Wallis H and Mann-Whitney U tests. The sensitivities and specificities for differentiating benign and malignant tumors at various cutoff values were calculated. Results The differences among the three parameters for malignant tumors, Warthin tumors, pleomorphie adenomas and other benign tumors were statistically significant （Х^2=8.627, 45.409, 50.938, P〈0.01 ）. The Kep values of malignant tumors were significantly lower than those of Warthin tumors. The Ktrans and Kep values of malignant tumors were significantly higher than those of pleomorphic adenomas, The Ktrans and Kep values of Warthin tumors were significantly higher than those of pleomorphic adenomas. At cutoff Kep value of 0.98 min^-1 and Ve of 0.351, the sensitivity and specificity of differential diagnosis between malignant and Warthin tumors were 75.0% and 76.27%, respectively. The cutoff Ktrans value of 0.28 min^-1 was 67.85% sensitive and 61.53% specific in differentiating malignancy from pleomorphic adenomas. At the Kep cutoff value of 0.69 min^-1, the sensitivity and specificity of differential diagnosis between malignancy and pleomorphic adenomas were 67.85% and 73.07%, respectively. Conclusion Quantitative parametric analysis of DCE-MRI contributes to pre-operative differential diagnostic of benign and malignant parotid tumors.