Objective To summarize the radiography ,CT and MRI findings of maxillary arteriovenous malformation (AVM ) . Methods Seventeen patients with maxillary AVM underwent panoramic radiography (3 patients) and enhanced MRI examination (6 patients) ,all the patient underwent enhanced CT examination .The clinical manifestation and imaging findings of maxillary AVM ,in‐cluding the location ,shape ,margin ,inner texture ,involvement of adjacent structures ,the density and signal intensity of the lesions , were analyzed .Results The lesions mainly located in molar areas (15/17) .The major clinical manifestation were repeated bleeding and acute bleeding .Other symptoms included swelling of the face ,pulsatile soft mass and anesthesia .The panoramic radiography only showed increased density .According to the change of the maxilla on enhanced CT images ,the lesions could be devided into two types :type Ⅰ ,showed intraosseous osteolytic destruction and cortical expansion (n=12);type Ⅱ ,showed“ground glass”appearance (n=5) .Bone destruction and soft tissue involvement ,widened feeding artery and draining veins ,elevated maxillary sinus were shown in all patients .External jugular vein enlargement and early enhancement (n=14) and root resorption (n= 6) were also detected . Flowing void on T1 and T2 weighted images (type Ⅰ) and hypo‐or isointense on T1WI ,hyperintense on T2WI and obvious enhance‐ment after injecting contrast material (type Ⅱ ) could observed .Conclusion Enhanced CT examination could be primarily recom‐mended and observe the extent of lesions and situation of vessels invaded of maxillary AVM .

Objective:To analyze imaging features on high resolution CT (HRCT) and MRI of facial nerve venous malformation (FNVM).Methods:A total of 23 patients with pathologically confirmed FNVM were retrospectively included from January 2016 to December 2020 in the Shanghai Ninth People′s Hospital, Shanghai Jiao Tong University School of Medicine. All patients underwent preoperative temporal bone HRCT, non-contrast MRI, diffusion weighted imaging (DWI) and dynamic contrast enhanced MRI (DCE-MRI). The location, morphology, and signal intensity of the lesions, as well as the enhancement pattern on DCE-MRI were reviewed. The time-intensity curve (TIC) was analyzed and the apparent diffusion coefficient (ADC) was measured.Results:The locations of FNVM lesions were geniculate ganglion ( n=19), mastoid segment ( n=1) and internal auditory canal ( n=3). Among 19 cases in geniculate ganglion, HRCT showed honeycomb-like bone change ( n=13) or expansive bone destruction with sharp border ( n=6). The case located in mastoid segment also presented as honeycomb-like changes. The other 3 cases in internal auditory canal presented with patchy hyperdensity bone change ( n=2) or resorptive bone destruction ( n=1). All 23 lesions demonstrated as irregular nodules with obviously heterogeneous enhancement on MRI. The lesions showed isointensity ( n=14), hypointensity ( n=8) or hyperintensity ( n=1) on T 1WI, and hyperintensity ( n=15) or isointensity ( n=8) on fat-suppression T 2WI. The ADC values of the lesions were (1.18±0.20)×10 -3 mm 2/s. A characteristic "point-to-plane" progressive enhancement pattern displayed on DCE-MRI, with type Ⅰ TIC (persistent pattern) presented. Conclusion:The imaging characteristics of FNVM are honeycomb-like bone changes on HRCT and"point-to-plane"progressive enhancement pattern on DCE-MRI.