Imaging methods in primary Sjögren's syndrome as potential tools of disease diagnostics and monitoring

Non-invasive imaging for predicting labial salivary gland biopsy outcomes in patients with suspected primary Sjögren syndrome

To identify the value of salivary gland ultrasound (SGUS) combined with magnetic resonance imaging (MRI) and magnetic resonance sialography (MRS) in predicting the results of labial salivary gland biopsy (LSGB) in patients with suspected primary Sjögren syndrome (pSS), and construct a nomogram model to predict LSGB results. A total of 181 patients who were admitted with suspected pSS from December 2018 to April 2023 were examined and divided into a training set (n = 120) and a validation set (n = 61). Baseline data of the two groups were examined, and the value of SGUS, MRI, and MRS in predicting LSGB was analyzed. Multivariate logistic analysis was used to screen for risk factors, and nomogram prediction models were constructed using these results. In the training set, the SGUS, MRI, and MRS scores of patients in the LSGB + group were higher than those in the LSGB - group (all P < 0.001). The positive prediction value (PPV) was 91% for an SGUS score of 3, and 82% for MRI and MRS scores of 2 or more. We developed a nomogram prediction model based on SGUS, MRI, and MRS data, and it had a concordance index (C-index) of 0.94. The Hosmer-Lemeshow test (χ2 = 3.17, P = 0.92) also indicated the nomogram prediction model had good accuracy and calibration for prediction of LSGB results. A nomogram model based on SGUS, MRI, and MRS results can help rheumatologists decide whether LSGB should be performed in patients with suspected pSS.

The value of MRI-based radiomics for evaluating early parotid gland injury in primary Sjögren's syndrome

OBJECTIVE

This study aimed to evaluate the value of machine learning models (ML) based on MRI radiomics in diagnosing early parotid gland injury in primary Sjögren's syndrome (pSS).

METHODS

A total of 164 patients (114 in the training cohort and 50 in the testing cohort) with pSS (n=82) or healthy controls (HC) (n=82) were enrolled. Itksnap software was used to perform two-dimensional segmentation of the bilateral parotid glands on T1-weighted (T1WI) and fat-suppressed T2-weighted imaging (fs-T2WI) images. A total of 1548 texture features of the parotid glands were extracted using radiomics software. A radiomics score (Radscore) was constructed and calculated. A t-test was used to compare the Radscore between the two groups. Finally, five machine learning models were trained and tested to identify early pSS parotid injury, and the performance of the machine learning models was evaluated by calculating the acceptance operating curve (ROC) and other parameters.

RESULTS

The Radscores between the pSS and HC groups showed significant statistical differences (p<0.001). Among the five machine learning models, the Extra Trees Classifier (ETC) model performed high predictive efficacy in identifying early pSS parotid injury, with an AUC of 0.87 in the testing set.

CONCLUSION

MRI radiomics-based machine learning models can effectively diagnose early parotid gland injury in primary Sjögren's syndrome.

Evaluation of Main Lacrimal Gland through Shear-wave Ultrasound Elastography in Patients with Low Schirmer Value

OBJECTIVE

To compare main lacrimal gland values through shear-wave elastography (SWE) in patients with low Schirmer value and unspecified Sjögren's syndrome (SS) with healthy controls.

MATERIAL AND METHOD

Admitted to the ophthalmology department with Schirmer value <10 mm, randomly selected 46 eyes of 46 patients evaluated for Sjögren's syndrome (SS) in the rheumatology department between December 2022 and April 2023 were classified as low Schirmer group (LSG). Randomly selected 48 eyes of 48 patients at a similar age with Schirmer value >10 mm were included as controls. Main lacrimal gland SWE measurements in LSG and control groups were recorded and compared as meter/second (m/sec).

RESULTS

Mean SWE values of the main lacrimal gland were measured as 2.78 ± 0.66 m/sec and 2.26 ± 0.29 m/sec in LSG and controls. SWE measurements were significantly higher in LSG patients than in controls (p<0.001). No significant correlation was found in the analysis between the Schirmer and the main lacrimal gland SWE values in LSG patients (p=0.702, r=0.058). No significant correlation was also detected between the Schirmer and main lacrimal gland SWE values in controls (p=0.097, r=0.242). No significant relationship was also found between age, gender, body mass index (BMI), and SWE values (p=0.351, p=0.493, p=0.328, respectively).

CONCLUSION

Mean SWE value of the main lacrimal gland was determined as significantly higher in patients with aqueous lacrimal insufficiency without SS than in controls. We consider that SWE measurements may be an imaging method to support the diagnosis of aqueous lacrimal insufficiency and used in follow-ups of those with dry eye syndrome (DES) in the future.

Textural Analysis of Magnetic Resonance Images as an Additional Evaluation Tool of Parotid Glands in Sjögren-Primarily Findings

Magnetic Resonance Imaging (MRI) plays a leading role in diagnosing soft tissue pathologies, especially in the head and neck. It is increasingly popular for evaluating salivary gland issues like neoplasms and Sjogren's Syndrome. Advanced MRI methods, including MRI sialography and texture analysis, offer non-invasive alternatives, enhancing MRI's role. This study focused on the relationship between the apparent diffusion coefficient (ADC) and T2-weighted MRI sialography and texture analysis (TA) of parotid glands in children with and without Sjogren's Syndrome (SS). Using 3.0 Tesla MRI with DWI and T2-weighted imaging, expended texture analysis, first-order statistics (FSOs), second-order, and higher-order statistics were conducted. The results showed significant differences in parotid ADC values, with lower values in the SS group, particularly in cases of higher disease activity. Lower kurtosis values were associated with more severe Tonami Scale grades. FSO parameters correlated well with the texture analysis from T2-weighted images, indicating promise in grading parotid gland inflammation. However, further research is needed to understand the impact of variables like binning and region of interest (ROI) size. This study highlights the potential of texture analysis for assessing parotid gland inflammation and emphasizes the need for more investigations in this area.

Value of magnetic resonance imaging and sialography of the parotid gland for diagnosis of primary Sjögren syndrome

AIM

To evaluate the utility of magnetic resonance imaging (MRI) and magnetic resonance sialography (MRS) for diagnosis of primary Sjögren syndrome (pSS) singly or integrated with 2016 American College of Rheumatology (ACR)/European League Against Rheumatic Diseases (EULAR) classification criteria.

METHODS

The diagnostic efficiencies of MRI, MRS, and labial salivary gland biopsy (LSGB) were evaluated. The prediction model was established by multivariate analysis. Finally, performance of the ACR/EULAR criteria was evaluated after addition of MRI + MRS or replacement of original items by MRI + MRS.

RESULTS

The combined use of LSGB + MRI + MRS provided the greatest diagnostic value. MRI and MRS grade had positive correlations with disease duration and pathological grade of the labial gland (both P < 0.001). MRI and MRS grade had positive correlations with xerostomia severity and negative correlations with unstimulated salivary flow rate (both P < 0.001). The consistency of MRI grade and MRS grade in the diagnosis of parotid gland lesions was poor (κ = 0.253, P < 0.001). The diagnostic efficiency of our prediction model (AUC 0.906) was similar to that of criteria from the ACR/EULAR (AUC 0.930). Adding MRI + MRS to the ACR/EULAR criteria improved the sensitivity (92.3% vs 90.8%), whereas the specificity remained the same (88.9% vs 89.1%). Replacing LSGB by MRI + MRS in the ACR/EULAR criteria decreased both sensitivity and specificity (88.1% vs 90.8% and 86.4% vs 89.1%, respectively).

CONCLUSION

The combined application of MRI and MRS has ideal clinical application value in the diagnosis of early-stage pSS. Validity of the ACR/EULAR criteria remains high after incorporation of MRI + MRS.

Correlations of MR Sialographic Gradings with the Clinical Measures of Sjögren's Syndrome

OBJECTIVES

Sjögren syndrome (SS) features salivary gland architectural changes such as ductal deformities and fat deposition secondary to inflammatory cell infiltrates; however, the anatomical and pathophysiological correlations of SS remain to be determined. This study aimed to determine the correlations of imaging findings based on the magnetic resonance (MR) sialography with the clinical and laboratory aspects of SS patients.

METHODS

We evaluated the MR sialographic findings of two pairs of parotid glands (PGs) and submandibular glands (SMGs) from 41 SS patients. The distinct MR sialographic features were then compared with the clinical symptoms, biological (anti-SSA/Ro antibody positivity), histological (labial gland focus score), and functional (salivary flow and scintigraphy) data.

RESULTS

Ductal deformities such as sialectasis in the PG ducts were exclusively observed in SS, and fat replacement in SMGs was more distinct in patients with SS than in non-SS sicca patients. Of the 82 PGs and SMGs from 41 SS patients, the grade of sialectasis in PGs on MR sialographic images and fat stage in SMGs showed strong correlations with anti-SSA/Ro-positivity. PG sialectasis was found more frequently in patients with dry mouth and decreased salivary gland function. A significant correlation was found between fat deposition in PGs and SMGs and decreased salivary gland function.

CONCLUSION

These results suggest that MR sialography is a reliable, adjunctive anatomical and functional study to assess SS. Detail aspects of sialectasis and fat accumulation encountered on MR sialography in SS patients can help physicians assume the disease status in SS.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:307-316, 2023.

Imaging characteristics of Sjögren's syndrome

The current workup of Sjögren's syndrome is based on diagnostic criteria involving a combination of histology, immunology, ophthalmology, and salivary flow. Several modern imaging techniques provide complementary and additional information to diagnosis, staging, and surveillance. In this review article, we discuss the characteristic salivary imaging findings seen with the most commonly utilized imaging modalities. We also discuss imaging findings of the central nervous system disorders associated with Sjögren's syndrome, including the neuromyelitis optica spectrum disorder, and provide a differential diagnosis of alternative etiologies that can mimic Sjögren's syndrome.

A Novel Technique for the Evaluation and Interpretation of Elastography in Salivary Gland Involvement in Primary Sjögren Syndrome

Ultrasound (US) of major salivary glands (MSG) evaluates echogenicity, border features and vascularization, with elastography, it can detect tissue elasticity and glandular fibrosis, related to inflammation in Primary Sjögren’s syndrome (pSS). This study aimed to develop a novel technique by pixel analysis for evaluation and interpretation of elastography in MSG in pSS. A cross-sectional and observational multicenter study was conducted. The US of MSG performed in orthogonal planes in grayscale, Doppler, and shear-wave elastography. For elastography images of each gland were analyzed with the open-source program ImageJ to perform a pixel analysis. Statistical analysis was performed with the IBM-SPSS v25 program. Fifty-nine women with a mean age of 57.69 (23–83) years were recruited; pSS mean duration of 87 (5–275) months, and 12 healthy women without sicca symptoms as a control group with a mean age of 50.67 (42–60) years. Intragroup analysis showed p-values >0.05 between sicca symptoms, ocular/dryness tests, biopsy, US, and pixel analysis; correlation between Hocevar and pixel analysis was not found (rho < 0.1, p >0.5). MSG anatomical size was 41.7 ± 28.2 mm vs. 67.6 ± 8.8 mm (p ≤ 0.0001); unstimulated whole saliva flow rate was 0.80 ± 0.80 ml/5 min vs. 1.85 ± 1.27 ml/5 min (p = 0.016). The elastography values (absolute number of pixels) were 572.38 ± 99.21 vs. 539.69 ± 93.12 (p = 0.290). A cut-off point risk for pSS identified with less than 54% of red pixels in the global MSG mass [OR of 3.8 95% CI (1.01–15.00)]. Pixel analysis is a new tool that could lead to a better understanding of the MSG chronic inflammatory process in pSS.

Shear wave elastography as a potential additional diagnostic tool in primary Sjögren's syndrome: an observational study

The primary aim of this study was to verify if shear wave elastography can be used to evaluate salivary gland involvement in primary Sjögren's syndrome (pSS). The secondary objective was to establish an accurate cut-off value for parotid and submandibular salivary gland stiffness and to verify whether there are any distinctions among pSS patients with or without subjective mouth dryness. This prospective study included 45 patients with pSS (2016 ACR/EULAR classification criteria) and 108 healthy controls. All subjects underwent bilateral shear wave elastography of the parotid and submandibular salivary glands. Clinical data of pSS patients were collected and compared to elastography results. Patients with pSS had significantly higher shear wave elastography values for the parotid and submandibular salivary glands than the controls. There were no statistical differences in SWE values between patients with or without mouth dryness. The optimal cut-off value (mean value of 4 salivary glands shear wave elastography results) to distinguish patients with or without pSS was 13.19 kPa with sensitivity = 97.8% and specificity = 100.0%. It was, therefore, confirmed that shear wave elastography measurement of salivary glands has strong predictive ability in pSS detection (AUC 97.8%, 95% CI 93.4-100.0%). Shear wave elastography seems to be a promising, non-invasive and simple quantitative adjunct test to support the diagnosis of pSS with good sensitivity and specificity. More extensive prospective studies are needed to standardize a study protocol.

Recurrent or persistent salivary gland enlargement in children: When is it Sjögren's?

OBJECTIVES

To describe characteristic features in children with recurrent or persistent salivary gland enlargement and to propose a diagnostic algorithm with specific consideration for Sjögren's disease (SD).

METHODS

In this single-center, prospective study, 45 patients < 18 years, with recurrent or persistent salivary gland enlargement of unknown etiology were enrolled from 2006 to 2019. We collected detailed clinical information to characterize this group of patients including specific details of their major salivary gland signs and symptoms. We compared clinical, laboratory and radiological parameters between 4 groups based on the results of labial salivary gland biopsy (LSGB) and between patients who met existing SD criteria or not.

RESULTS

44 patients, with a mean age of 6.8 years and female to male ratio 21:23 were observed over a mean of 3.8 years. Characteristics of salivary gland swelling episodes varied considerably between individuals, but the majority experienced ≤5 episodes per year, lasting ≤ 1 week, with swelling affecting either or both glands. Ocular and oral dryness symptoms were observed only in 25% and 59% patients, respectively. The majority were positive for ANA, but negative for SD-specific antibodies. A total of 75% patients fulfilled at least one of the existing SD criteria.

CONCLUSION

SD is a major cause of recurrent salivary gland enlargement in children. For children meeting adult criteria, the diagnosis of SD is clear. However, for the many children without dryness symptoms, objective dryness, or SD-specific antibodies, further workup including a combination of salivary gland imaging and histopathological examination can help establish the diagnosis of SD.

Ultrasound and Bioptic Investigation of Patients with Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic and heterogeneous disorder characterized by a wide spectrum of glandular and extra-glandular features. The hallmark of pSS is considered to be the immune-mediated involvement of the exocrine glands and B-cell hyperactivation. This leads pSS patients to an increased risk of developing lymphoproliferative diseases, and persistent (>2 months) major salivary gland enlargement is a well-known clinical sign of possible involvement by B cell lymphoma. Better stratification of the patients may improve understanding of the mechanism underlying the risk of lymphoproliferative disorder. Here, we summarize the role of different imaging techniques and a bioptic approach in pSS patients, focusing mainly on the role of salivary gland ultrasonography (SGUS) and a US-guided core needle biopsy (Us-guided CNB) as diagnostic and prognostic tools in pSS patients with persistent parotid swelling.

Imaging in Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by dysfunction and lymphocytic infiltration of the salivary and lacrimal glands. Besides the characteristic sicca complaints, pSS patients can present a spectrum of signs and symptoms, which challenges the diagnostic process. Various imaging techniques can be used to assist in the diagnostic work-up and follow-up of pSS patients. Developments in imaging techniques provide new opportunities and perspectives. In this descriptive review, we discuss imaging techniques that are used in pSS with a focus on the salivary glands. The emphasis is on the contribution of these techniques to the diagnosis of pSS, their potential in assessing disease activity and disease progression in pSS, and their contribution to diagnosing and staging of pSS-associated lymphomas. Imaging findings of the salivary glands will be linked to histopathological changes in the salivary glands of pSS patients.

Applicability of shear wave elastography for the evaluation of skin strain in systemic sclerosis

The assessment of skin fibrosis is vital for the diagnosis and monitoring of treatment in the systemic sclerosis (SSc)-a severe autoimmune disease. The elastography is a technique of skin fibrosis assessment through the evaluation of skin strain. We compared the efficacy of the shear wave elastography (SWE) and commonly used modified Rodnan skin score (RSS) in skin fibrosis assessment in SSc. The study included 40 SSc patients and 28 healthy individuals, with the exclusion of individuals with other skin/autoimmune diseases. Skin thickness using RSS and skin strain using SWE were assessed in the same 20 body localizations. Subjects' informed consent and the bioethics committee approval were obtained. Elastographic skin strain correlated positively with both partial and overall RSS values, with strong positive correlation (r ≥ 0.75) for hands and fingers localizations in particular. In SSc patients with normal RSS values, the elastographic strain was significantly higher than in healthy controls. Elastographic strain of fingers' skin evaluated in SWE is highly accurate for distinguishing SSc patients (sensitivity 0.897-0.923, specificity 0.929-0.964, positive predictive value 0.946-0.973, negative predictive value 0.867-0.900). ESW results are substantially more reproducible than those of RSS examination (intraclass correlation coefficients: 0.987 vs. 0.941). The shear wave elastography is more reproducible and has higher sensitivity than RSS in the evaluation of skin condition in SSc, especially in case of changes non-detectable on physical evaluation, indicating it might become a useful tool in SSc diagnosis.