Whole-Volume ADC Histogram Analysis of Parotid Glands to Identify Patients With Sjögren's Syndrome

Background: There was no functional MR sequences have been reported in identifying Sjogren’s syndrome in patients suspected of the disease. Methods: The 2002 AECG classification criteria were used to diagnose Sjogren's syndrome. A total of 52 patients with Sjogren’s syndrome and 24 patients suspected of having the disease prospectively underwent 3.0 T magnetic resonance (MR) scanning including diffusion weighted (DW) imaging (b = 0, 1000 s/mm2). Whole-volume ADC histogram analysis generated ADCmean, skewness, kurtosis and entropy values of bilateral parotid glands. Continuous variables were compared with two independent samples t-test and categorical variables were compared with Fisher’s test between the two groups. The diagnostic performance of the indexes was evaluated with receiver operating characteristic (ROC) analysis. Findings: Fisher’s tests showed that some clinical indexes and MR morphology grade differed significantly between Sjogren’s syndrome and suspected patients (all p ≤ 0.001). The parotid entropy value of patients with Sjogren’s syndrome was significantly higher than that of patients suspected of the disease (p < 0.001). Among MR parameters, entropy combined with kurtosis performed best in differentiating patients with Sjogren’s syndrome from those suspected of having Sjogren’s syndrome (AUC= 0.955). Interpretation: Whole-volume ADC histogram analysis could provide a series of parameters reflecting tissue characteristics, proved useful in the diagnosis of Sjogren’s syndrome. Funding Statement: The study design was supported by the National Natural Science Foundation of China (ID: 81371516, 81501441). The collection, analysis and interpretation of data was supported by the Foundation of National Health and Family Planning Commission of China (ID: W201306), the Social Development Foundation of Jiangsu Province (ID: BE2015605) and the Key Project and Outstanding Youth supported by Medical Science and Technology Development Foundation Nanjing Department of Health (ID: YKK15067). The writing of the report was supported by the Jiangsu province key medical young talents, "13th Five-Year" health promotion project of Jiangsu province (ID: JH.2016-2020). The decision to submit the paper for publication was supported by the Natural Science Foundation of Jiangsu Province (ID: BK20171118). Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: The ethics committee of Nanjing Drum Tower Hospital approved this study. Written informed consent was obtained from all subjects.