| Part ?:Utilization of T1? MR imaging to detect parotid gland abnormilities in early-stage Sjogren's syndrome patientsObjective:To explore the feasibility of parotid spin-lattice relaxation time in the rotating frame(T1?)MR imaging in the diagnosis of Sjogren's syndrome(SS)without morphological changes of the parotid glands.Methods:The study enrolled thirty-two consecutive SS patients without morphological changes of parotid glands and 32 age-and gender-matched healthy volunteers who underwent parotid 3.0 T MR imaging,including T1? sequences.Follow up imaging was performed at 3 months.T1 signal intensities and T1? values of bilateral parotid glands were compared using paired samples t-test.Parotid T1 signal intensities and T1? values were compared using two independent samples t-test.Diagnostic performance of the parotid T1? values,was evaluated by Receiver operating characteristic analysis.The intraclass correlation coefficient(ICC)was calculated to evaluate the reproducibility of parotid T1? measurements.Results:There were no significant differences of T1 signal intensities and T1? values between bilateral parotid glands in SS patients and healthy volunteers(P = 0.170,0.886 and 0.942,0.229,respectively).The parotid T1? values of SS patients(96.47 ±15.38 ms)were significantly higher than those of healthy volunteers(84.25 ±6.11 ms)(P<0.001),while there were no significant differences of T1 signal intensities between SS patients and healthy volunteers(P = 0.655).With a cutoff value of 88.02 ms,the sensitivity and specificity of the parotid T1? value was 75.0%and 100.0%in the diagnosis of SS.The reproducibility of parotid T1? measurement was excellent(ICC:0.934-0.995).Conclusion:Parotid T1? MR imaging hold a potential role in diagnosing SS without morphological changes of parotid glands.Part ?:Correlation between intravoxel incoherent motion MR parameters and MR nodular grade of parotid glands in patients with Sjogren's syndromeObjective:To explore the correlation between intravoxel incoherent motion(IVIM)magnetic resonance(MR)parameters and MR nodular grade of parotid glands in patients with Sjogren's syndrome(SS).Methods:A total of 31 consecutive patients with SS and 28 gender-and age-matched healthy volunteers underwent bilateral parotid 3.0T MR examination including the IVIM sequence(9b values,0?800 s/mm2).The apparent diffusion coefficient(ADC),diffusion coefficient D,pseudo-diffusion coefficient D*,and perfusion fraction f of bilateral parotid glands were obtained,and the nodular grade of each parotid gland was evaluated according to the MR morphological appearance.Results:Sixty-two parotid glands in 31 patients with SS consisted of 32,14,8,and 8 parotid glands at MR nodular grades 0,1,2,and 3,respectively.In parotid glands of grade 0,1,2,3 and healthy volunteers,the ADC values were(1.13± 0.25,1.11 ± 0.17,1.05 ± 0.24,0.89 ± 0.04,1.00 ±0.21)×10-3 mm2/s,D values were(0.92 ± 0.13,0.90± 0.19,0.90 ± 0.03,0.67 ± 0.03,0.81 ± 0.03)×10-3 mm2/s,f values were 0.20 ± 0.04,0.18 ± 0.02,0.15 ± 0.01,0.11 ± 0.01,0.15 ± 0.06,and D*values were(53.89 ± 28.26,41.78 ± 16.35,51.24 ± 18.69,31.83 ± 18.03,36.83 ± 16.14)x10-3 mm2/s respectively.The ADC,D,f,and D*values of parotid glands in patients with SS at grade 0 were significantly higher than those in healthy volunteers(all P<0.05).Significant differences were observed in the D and f values of parotid glands in patients with SS among different grades(P = 0.003,<0.001,respectively).The IVIM parameters(D,f)of parotid glands at early(grades 0-1)and advanced(grades 2-3)stages in patients with SS were significantly higher and lower,respectively,than those in healthy volunteers(all P<0.05).The D and f values inversely correlated with MR nodular grades significantly(r =-0.297,P = 0.019;r =-0.653,P<0.001,respectively).Conclusion:The parotid glands with different MR nodular grades in patients with SS showed different IVIM parameters,reflecting different pathophysiological characteristics of parotid glands at different stages. |
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