Application Of Parotid Gland ASL And T2 Mapping MRI In Sj(?)gren’s Syndrome

Objectives: Sj(?)gren’s syndrome(SS)is a systemic autoimmune disease with unknown etiology.Its clinical characteristics are dry mouth and dry eye,with salivary and lacrimal gland involvement being the most common.Arterial spin labeling(ASL)and T2 mapping technology can evaluate the changes of parotid gland in SS patients in terms of microcirculation perfusion and tissue structure,respectively.At present,there are few studies on parotid gland injury in SS patients by ASL and T2 mapping technology at home and abroad.This study aims to research the application value of arterial spin labeling(ASL)and T2 mapping in the assessment of parotid gland injury and early diagnosis in SS patients.Methods: This study Prospectively included 54 SS patients and 30 healthy volunteers who were diagnosed in Shengjing Hospital affiliated to China Medical University from August 2021 to October 2022 for the first time.All SS patients and healthy volunteers received routine magnetic resonance imaging(MRI),ASL and T2 mapping examinations of bilateral parotid glands.Two doctors manually drew the area of interest(ROI)in the ASL pseudo-color image,T1 WI fusion image and T2 mapping image to obtain the blood flow(BF),T2 value and T2 standard deviation of parotid gland.The patients with SS were divided into 0-4 grades by them according to the MRI morphological grading criteria.The non-parametric Mann-Whitney U test was used to compare the differences of ASL and T2 mapping parameters between SS patients and healthy volunteers.The non-parametric Kruskal-Wallis test was used to contrast the distinction of ASL and T2 mapping parameters between adjacent MRI morphological grades.And the correlation between MRI morphological grading of parotid gland and parameters of ASL and T2 mapping in SS patients was tested by Spearman rank correlation test.The diagnostic efficacy of ASL and T2 mapping parameters and their combination in distinguishing healthy volunteers from early SS patients and all SS patients was evaluated by logistic regression combined with receiver operating characteristic(ROC)curve.Results : The parotid gland BF of SS patients is higher than that of healthy volunteers(P<0.05).The BF of patients with grade 0-3 SS was higher than that of healthy volunteers(P<0.05).There was no significant difference between the BF of patients with grade 4 SS and healthy volunteers(P=0.699).The parotid gland T2 value and standard deviation of T2 value in SS patients are higher than those in healthy volunteers(P<0.05).The T2 value and standard deviation of T2 value of parotid gland in healthy volunteers were lower than those of SS patients of 0-4 grades(P<0.05).MRI morphology grading of parotid gland(0-4 grade)was weakly correlated with BF(r=0.323,P=0.001).MRI morphological grading of parotid gland(0-3 grades)was strongly correlated with BF(r=0.785,P<0.001).There was a moderate positive correlation between the MRI morphological grading of parotid gland and T2value(r=0.547,P<0.001),and There was a moderate positive correlation between the MRI morphological grading of parotid gland and the standard deviation of T2value(r=0.622,P<0.001).The area under the curve(AUC)of BF was 0.813,the sensitivity was 81%,and the specificity was 77%;The AUC of T2 value was 0.810,the sensitivity was 79%,and the specificity was 70%;The AUC of the standard deviation of T2 was 0.649,the sensitivity was 64%,and the specificity was 65%.The AUC of the combined diagnosis of BF,T2 and standard deviation of T2 was 0.842,the sensitivity was 93%,and the specificity was 65%.The diagnostic efficacy of BF,T2 and combined diagnosis was higher than the standard deviation of T2(P=0.019,P=0.002,P=0.001).The diagnostic efficacy of combined diagnosis is higher than BF or T2,but the difference is not significant(P=0.409,P=0.237).Conclusions: BF,T2 and standard deviation of T2 of the parotid gland can distinguish healthy volunteers from SS patients.BF,T2 value and standard deviation of T2 value can reflect the corresponding changes of parotid gland in SS patients with different degrees of fat deposition.The combination of BF,T2 value and T2 value can improve the diagnostic efficiency.ASL technology and T2 mapping technology have certain significance in the assessment and early diagnosis of parotid gland injury in SS patients,and are important supplementary tools for routine MRI diagnosis.