Abstract:  Objective To provide reliable basis for the diagnosis of adenoid cystic carcinoma (ACC) of lacrimal gland by characterizing 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 retrospectively for 26 cases, including location, morphology, margin, extent, signal intensity and the patterns of contrast. Dynamic contrast-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(typeⅠ, persistant enhancement type；type Ⅱ, platform type; tye Ⅲ, 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. Inhomogeneous enhancement was shown in 25 cases, with cystic degeneration and necrosis in 16 cases. The CIpeak, 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±0.30×10-3 mm2·s－1. Conclusion MRI can display clearly the location, orphology, extent, margin and bone destruction of lacrimal gland ACC. DCE and DWI can provide assistant quantitative features for diagnosis of lacrimal gland ACC.  (Ophthalmol CHN, 2013, 22: 314-319)

Key words: lacrimal gland, adenoid cystic carcinoma, magnetic resonance imaging