摘要目的：探讨干燥综合征（ SS）的腮腺MRI表现特点。方法收集因口干于本院就诊的27例患者，根据SS国际分类诊断标准，分为SS组（21例）和非SS组（6例）。另外选取10名健康志愿者作为对照组。所有受试者均行常规腮腺MRI检查和双侧腮腺导管MR成像（ MRS）。观察T1 WI和T2 WI上信号强度的标准差，并进行脂肪信号分级和腮腺导管扩张程度分级。以临床诊断为金标准，评价常规MRI、MRS及二者联合应用对SS的诊断效能。采用单因素方差分析比较3组受试者腮腺信号强度标准差的差异，采用配对四格表χ2检验比较常规MRI和MRS诊断SS的差异，采用一致性检验比较SS组2种分级结果的一致性。结果对照组和非SS组受试者腮腺常规MRI信号均匀；SS组患者均为双侧腮腺病变，表现为腮腺信号不均匀，T1 WI和T2 WI上均见多发弥漫分布的高信号，在抑脂T2 WI上呈低信号；42个腮腺的脂肪信号分级，0级2个、1级10个、2级10个、3级6个、4级14个。 MRS上对照组和非SS组受试者均未见腮腺末梢导管扩张；SS组患者均为双侧腮腺病变，表现为弥漫性腮腺末梢导管扩张；42个腮腺的腮腺导管扩张程度分级，0级12个、1级8个、2级10个、3级5个、4级7个。 SS组、非SS组和对照组腮腺T1 WI 信号强度的标准差分别为124.1±30.0、81.8±27.6和86.3±35.0，T2 WI信号强度的标准差分别为115.1±35.2、69.8±23.5和80.1±31.4， SS组信号强度的标准差均高于非SS组和对照组，差异有统计学意义（ F值分别为13.780和13.301， P值均＜0.01）；而非SS组和对照组腮腺信号强度标准差差异无统计学意义（P＞0.05）。21例SS患者的42个腮腺中，常规MRI和MRS分别检出病变腮腺40和30个，均无假阳性结果，差异有统计学意义（χ2＝13.04，P＝0.013），而2种方法联合应用检出了全部42个病变腺体。脂肪信号分级和腮腺导管扩张程度分级方法诊断SS组患者病变腮腺的一致性较差（Kappa＝0.12，P＝0.092）。结论 SS患者腮腺常规MRI的弥漫性脂肪沉积和MRS的弥漫性末梢导管扩张均为特征性表现。常规MRI作为SS的首选检查手段，联合应用MRS可提高诊断准确性。

abstractsObjective To investigate MR imaging features of parotid gland in Sj?gren′s syndrome ( SS).Methods Twenty-seven cases of xerostomia patients were collected and divided into SS group ( n=21) and non-SS group (n=6) according to the international classification (diagnosis) criteria for SS.Ten healthy volunteers were recruited as the control group.All the subjects underwent conventional MRI of parotid gland and MR sialography ( MRS).Standard deviation of T 1 WI and T2 WI signal intensity among 3 groups was observed, meanwhile, grading was made according to parotid glands , fat signal and parotid duct expansion degree respectively.With clinical diagnosis as the gold standard , diagnostic value of conventional MRI , MRS and their combination used in SS was compared.One-way ANOVA was used in comparison of standard deviation of parotid gland′s signal intensity among 3 groups , and Chi-square test was applied in comparison of conventional MRI and MRS diagnostic value.Moreover , Kappa value was calculated to assess the consistency of two grading results in SS.Results Signal intensity of parotid glands in control group and non-SS group was homogeneous.However , bilaterally diffused and heterogeneous high signal intensity on both T1WI and T2WI was found in SS patients, which was depressed on T2WI fat suppression sequences.Forty-two parotid glands were graded by fat signal:Grade 0 (n=2 glands), Grade 1&nbsp;(n=10), Grade 2 (n=10), Grade 3 (n=6) and Grade 4 (n=14).Parotid peripheral ducts of control group and non-SS group were unexpanded , while bilaterally expanded parotid peripheral ducts were shown in SS patients.The grading of 42 parotid glands by expansion degree of parotid duct , Grade 0 was rated in 12, Grade 1 in 8, Grade 2 in 10, Grade 3 in 5, and Grade 4 in 7.Standard deviation of T1WI signal intensity of parotid glands among SS group , non-SS group and control group were 124.1 ±30.0, 81.8 ±27.6, and 86.3 ±35.0 respectively;and standard deviation of T 2 WI signal intensity were 115.1 ±35.2, 69.8 ±23.5, and 80.1 ±31.4 respectively; the standard deviation of T 1 WI and T2 WI signal intensity of SS group was higher than both non-SS group and control group′s ( F value =13.780 and 13.301, respectively, P <0.01), however, the difference of standard deviation of signal intensity of non-SS group and control group had no statistical significance (P>0.05).Among 42 parotid glands with SS, conventional MRI and MRS showed parotid gland lesions in 40 and 30 respectively , and the difference was statistically significant (χ2 =13.04, P=0.013).There was no false positive result.The combination of the two methods detected all 42 lesions.The consistency of detecting parotid abnormalities with SS between conventional MRI and MRS was poor (Kappa=0.12, P=0.092).Conclusions Diffuse fatty infiltration on conventional MRI and diffuse peripheral duct dilatation on MRS in the parotid gland are characteristic features of SS , and conventional MRI could be used as the preferred technique for the SS.combination with MRS may improve diagnostic accuracy.