Evaluation of extraocular muscles in patients with thyroid associated ophthalmopathy using apparent diffusion coefficient measured by magnetic resonance imaging before and after radiation therapy.

BACKGROUND: Thyroid-associated ophthalmopathy (TAO) is an autoimmune orbital disease characterized by edema of extraocular muscles (EOMs). PURPOSE: To characterize the inflammation of EOMs in patients with TAO before and after radiation therapy using apparent diffusion coefficient (ADC) and to analyze the correlation between ADC and clinical activity of TAO. MATERIAL AND METHODS: The ADCs of superior rectus (SR), inferior rectus (IR), medial rectus (MR), and lateral rectus (LR) muscles were measured in 52 eyes of 26 patients with TAO before and three months after orbital radiation therapy. In addition, 38 eyes of 20 healthy volunteers were included. The clinical activity score (CAS) was evaluated. The ADC maps were reconstructed and measured on the coronal diffusion-weighted imaging (DWI) sequence and calculated in mm2/s. RESULTS: The mean ADCs of EOMs before treatment were 1.42 ± 0.23 in SR, 1.37 ± 0.23 in IR, 1.41 ± 0.21 in MR, and 1.28 ± 0.25 in LR. The mean ADCs after treatment were 1.27 ± 0.18, 1.22 ± 0.26, 1.30 ± 0.22, and 1.15 ± 0.21, respectively. The ADCs were significantly decreased after treatment (all P < 0.001). The ADCs of patients with TAO were significantly higher than those of controls. There was a statistically significant correlation between the mean ADCs and the CAS in each patient with TAO both before and after treatment (before: r = 0.520; P < 0.001; after: r = 0.625; P < 0.001). CONCLUSION: The ADC values of EOMs can be exploited as a quantitative indicator to evaluate the clinical activity and monitor the therapeutic responses of patients with TAO.

Imaging characteristics analysis of high resolution CT and MRI of facial nerve venous malformation / 中华放射学杂志

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.

Imaging features of the arteriovenous malformation in maxilla / 实用放射学杂志

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 .