泪腺腺样囊腺癌的MRI特征分析

MRI features of adenoid cystic carcinoma of the lacrimal gland

目的探讨泪腺腺样囊腺癌(adenoid cystic carcinoma,ACC)的MRI特征,为临床早期诊断提供依据。设计回顾性病例系列。研究对象北京同仁医院经手术证实ACC患者26例,术前均行MRI扫描。方法所有ACC患者常规MRI扫描;同时对动态增强磁共振成像(DCE-MRI)及磁共振扩散加权成像(DWI)图像进行后处理获得相应量化指标。主要指标ACC动态增强的峰值强化指数(CIpeak)、峰值强化时间(Tpeak)、最大强化指数(CImax)、强化指数曲线(I型为持续上升型,II型为平台型,III型为流出型)、肿瘤平均表观扩散系数(ADC)值。结果 26例均起自泪腺眶部,20例形态不规则,14例边界不清,12例边界清晰,6例累及颅内,9例出现骨质破坏。T1WI呈等或略低信号,其中3例内部出现高信号区;T2WI呈等或稍高信号为主,增强后仅1例强化均匀,25例呈不均匀强化,其中16例伴有内部囊变、坏死区。泪腺ACC峰值强化指数(CIpeak)为0.9±0.41,峰值强化时间(Tpeak)为(109.3±58.5)s,最大强化指数(CImax)为0.95±0.45。22例时间强化指数曲线中2例为I型,14例为II型,6例为III型。平均ADC值为(1.25±0.30×10-3)mm2·s-1。结论 MRI可以清晰显示泪腺ACC的部位、形态、范围、边界及骨质侵犯,DCE-MRI及DWI为肿瘤的诊断及鉴别诊断提供辅助量化特征。

Objective To provide reliable basis for the diagnosis of adenoid cystic carcinoma （ACC） of lacrimal gland by charac- terizing the MRI manifestations. Design Retrospective case series. Participants Twenty-six cases of ACC confirmed by operation and pathology. All the patients performed MRI scan before the surgery. Methods The characteristics of the routine MRI were evaluated ret- rospectively for 26 cases, including location, morphology, margin, extent, signal intensity and the patterns of contrast. Dynamic con- trast-enhanced magnetic resonance imaging （DCE-MRI） and diffusion weighted imaging （DWI） were processed to get the quantitative indexes. Main Outcome Measures CIpeak,Tpeak, CImax, type of time-contrast index curve （type I, persistant enhancement type;type 1], platform type; tye m, washout type） and ADC value. Results All the tumors of 26 cases originated from orbital lobes, with irregular shape in 20 cases, ill-defined margin in 14 cases and well-defined margin in 12 cases. Intracranial infiltration was shown in 6 cases and bone destruction in 9 cases. The masses showed isointensity or mild hypointensity on T1WI and isointensity or slight hyperintensity on T2WI, while hyperintensity on T1WI appeared in 3 cases. Inhomogeneons enhancement was shown in 25 cases, with cystic degeneration and necrosis in 16 cases. The Clpeak, Tpeak and CImax of the tumor were 0.9±0.41, 109.3±58.5 s and 0.95±0.45, respectively. The patterns of time-contrast index curves were type I in 2 cases, type II in 14 cases and type III in 6 cases. The mean ADC value for ACC of lacrimal gland was 1.25±0.30x10. mm2.s-1. Conclusion MRI can display clearly the location, morphology, extent, margin and bone destruction of lacrimal gland ACC. DCE and DWI can provide assistant quantitative features for diagnosis of lacrimal gland ACC.