Thyroid-Associated Orbitopathy: Evaluating Microstructural Changes of Extraocular Muscles and Optic Nerves Using Readout-Segmented Echo-Planar Imaging-Based Diffusion Tensor Imaging

OBJECTIVE: We aimed to investigate the ability of readout-segmented echo-planar imaging (rs-EPI)-based diffusion tensor imaging (DTI) in assessing the microstructural change of extraocular muscles (EOMs) and optic nerves in patients with thyroid-associated orbitopathy (TAO) as well as in evaluating disease activity.MATERIALS AND METHODS: We enrolled 35 TAO patients and 22 healthy controls (HCs) who underwent pre-treatment rs-EPI-based DTI. Mean, axial, and radial diffusivity (MD, AD, and RD) and fractional anisotropy (FA) of the medial and lateral EOMs and optic nerve for each orbit were calculated and compared between TAO and HC groups and between active and inactive TAO groups. Factors such as age, sex, disease duration, mediation, and smoking history between groups were also compared. Logistic regression analysis was used to evaluate the predictive value of significant variables for disease activity.RESULTS: Disease duration was significantly shorter in active TAOs than in inactive ones (p < 0.001). TAO patients showed significantly lower FA and higher MD, AD, and RD than HCs for both medial and lateral EOMs (p < 0.001), but not the AD value of lateral EOMs (p = 0.619). Active patients had significantly higher FA, MD, and AD than inactive patients for medial EOMs (p < 0.005), whereas only FA differed significantly in the lateral EOMs (p = 0.018). The MD, AD, and RD of optic nerves were significantly lower in TAO patients than HCs (p < 0.05), except for FA (p = 0.129). Multivariate analysis showed that the MD of medial EOMs and disease duration were significant predictors for disease activity. The combination of these two parameters showed optimal diagnostic efficiency for disease activity (area under the curve, 0.855; sensitivity, 68.4%; specificity, 96.9%).CONCLUSION: rs-EPI-based DTI is promising in assessing microstructural changes of EOMs and optic nerves and can help to indicate the disease activity of TAO, especially through the MD of medial EOMs.

Clinical value of high-resolution T2-weighted magnetic resonance imaging combined with readout-segmented echo-planar imaging in differential diagnosis of muscle and non-muscle invasive bladder cancer / 第二军医大学学报

Objective To evaluate the clinical value of high-resolution T2-weighted magnetic resonance imaging (HR-T2WI), readout-segmented echo-planar imaging (RS-EPI) and HR-T2WI plus RS-EPI in differentiating non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC). Methods A prospective study was conducted on 95 patients with bladder cancer identified by cystoscope biopsy, who underwent surgery treatment in our hospital from Jun. 2016 to Dec. 2017. All 95 patients had clear pathological staging, and received HR-T2WI and RS-EPI examination. NMIBC and MIBC were differentiated using HR-T2WI, RS-EPI and HR-T2WI plus RS-EPI, and the diagnosis results were compared with the pathological results using Kappa test. The receiver operating characteristic (ROC) curve was drawn and the area under curve (AUC) of ROC was calculated to evaluate the sensitivity, specificity, accuracy of HR-T2WI, RS-EPI and HR-T2WI plus RSEPI. DeLong test was used to compare the AUC of three methods. Results The diagnostic results of HR-T2WI, RS-EPI and HRT2WI plus RS-EPI had good agreement with the pathological results (Kappa=0.770, 0.787 and 0.936; all P<0.01). The AUC, sensitivity, specificity and accuracy of HR-T2WI, RS-EPI and HR-T2WI plus RS-EPI were 0.899, 95.5% (42/44), 82.4% (42/51) and 88.4% (84/95), 0.891, 84.1% (37/44), 94.1% (48/51) and 89.5% (85/95), and 0.966, 93.2% (41/44), 100.0% (51/51) and 96.8% (92/95), respectively. The AUC of HR-T2WI+RS-EPI was higher than that of HR-T2WI and RS-EPI (Z=-2.627 8 and -2.720 5, P=0.008 6 and 0.006 5). Conclusion HR-T2WI plus RS-EPI can be used as a preoperative non-invasive examination method to differentiate NMIBC and MIBC.