中文摘要：

目的探讨乳腺导管乳头状瘤（IP）的MRI表现，提高对IP的认识和术前诊断准确性。方法回顾性分析经手术病理证实的24例IP的MRI表现，包括形态学、平扫信号强度、增强扫描病变内部强化方式及其动态变化特征和时间-信号强度曲线（TIC）类型、DWI上ADC值。采用配对设计资料t检验比较IP和正常乳腺组织ADC值的差异。结果24例IP最大径0．3～2．0cm。17例呈圆形或卵圆形，7例不规则形；边界18例清晰，6例欠清。平扫T1WI呈等或稍低信号，T2W1呈稍高信号。动态增强扫描早期时相肿瘤均明显强化，15例呈较均匀强化，9例强化欠均匀，早期强化率平均值为（156.50±19．67）％，延迟时相18例表现为肿瘤边缘部分信号强度高于中心部分，而呈“环形”表现。TIC19例呈Ⅲ型，5例呈Ⅱ型。b值为1000s／mm^2时，平均ADC值为（1．14±0．29）×10^-3mm^2／s，低于正常乳腺组织的ADC值[（1．83±0．32）×10^-3mm^2／s]，差异有统计学意义（t=5．53，P=0．000）。结论IP的动态增强扫描TIC类型和DWI上ADC值表现与乳腺癌相似，动态增强扫描早期强化率和内部强化方式的动态变化特征上具有特征性。

英文摘要：

Objective To characterize the MR features of intraductal papilloma of the breast. Methods The MRI data of 24 patients with intraductal papillomas of the breast verified by histopathology were analyzed. The MRI features analyzed included morphology, signal intensity on pre-enhanced Tl WI and FE T2WI, the patterns of dynamic enhancement, and the mean ADC on DWI. The ADC values for intraductal papilloma and normal breast tissue were compared using paired t test. Results The maximum diameter of the tumors ranged from 0. 3 cm to 2. 0 era. Of the 24 tumors, 17 were round or oval and 7 were irregular in shape; the margins were well-defined in 18 cases, and ill-defined in 6 cases. All tumors were isointensity or hypointensity on Tl WI, and slight hyperintensity on T2WI. On dynamic enhanced images, all the 24 tumors showed rapid initial enhancement, and the mean early phase enhancement rate was （156. 50 ±19.67 ）%. In the early phase, homogenous enhancement was shown in 15 cases and heterogeneous enhancement in 9 cases. In the delayed phases, the most tumors （18/24） had ring-like enhancement pattern in which signal intensity in peripheral is higher than that in center. The patterns of time-signal intensity curves were type Ⅲ （washout） in 19 cases and type Ⅱ （plateau） in 5 cases. With b = 1000 s/mm^2, the mean ADC value for intraductal papilloma [ （ 1.14 ±0. 29） ×10^-3mm^2/s] was significantly lower than that of the normal breast tissue [ （1.83 ±0. 32） ×10^-3mm^2/s] （t = 5.53, P =0. 000）. Conclusions MRI features of intraductal papilloma are similar to breast cancer in washout pattern on DCE-MRI and lower ADC value on DWI. However, relative lower early enhancement rate and dynamic signal intensity course on DCE-MRI are characteristic clues to differentiating intraductal papilloma from breast cancer.