**3.6 Sjögren's syndrome**

Primary Sjögren's syndrome (pSS) is an autoimmune disease of the exocrine glands, which manifests mainly as hyposecretion of salivary and lacrimal glands. The diagnosis approach is generally focused on the detection of specific autoantibodies, positive ocular tests and findings of characteristic histopathological abnormalities. Sialography and scintigraphy are considered invasive and rarely used in everyday practice, while limited accessibility and the high cost of MRI also hinders its use. Studies on ultrasound have produced promising results for the assessment of major salivary glands (**Figure 12**) of pSS patients and offer a more accessible and less time-consuming alternative to other imaging tests. Still, the established

### **Figure 11.**

*Elastography of the finger volar aspect that shows the increased hardness of the epidermis and dermis, as shown by the blue color and the hardness percent.*

diagnostic criteria developed up until now for pSS have not included ultrasonography as a recommended diagnostic tool.

The parotid and submandibular glands can be easily examined for certain structural abnormalities, such as: parenchymal inhomogeneity, hypo-anechoic or hyperechoic areas (**Figure 12b** and **c**) (produced by cysts or calcifications), surface irregularities and changes in glandular size, intra- or periglandular lymph nodes [56].

Additionally, the use of Doppler modes can identify glandular hypervascularization which has been consistently observed in pSS patients. In early phases, US is marked by an increase in glandular volume and high vascularity, while in later stages reduced volume and hypovascularization are characteristic [57]. Parenchymal inhomogeneity is the most recognizable term used in the development of numerous grading systems.

Research carried out by De Vita et al. [58], Hocevar et al. [59] and Salaffi et al. [60] provided some of the well-known semiquantitative scoring systems. All of these US scores proved high sensitivity and specificity for pSS. De Vita et al. developed a 0-3 scale for parenchymal inhomogeneity, while Hocevar et al. added 0-3 scales also for the number of hypoechogenic areas, hyperechogenic reflections and clearness of salivary gland border. Salaffi et al. proposed an extended 0-4 scale for parenchymal inhomogeneity which includes all of the features previously mentioned (see **Table 6**) [60].

Minor salivary gland biopsy remains the gold standard for diagnosis and is recommended in most patients with suspected pSS, especially in cases with positive autoantibodies. Studies evaluated the predictive value of salivary gland US for histopathology abnormalities. Miedany et al. [61] found a significant correlation between US score and histopathological score (*r* = 0.82). This supports the use of US when biopsy cannot be performed or in order to stratify the at-risk patients before ordering a biopsy.

**Figure 12.**

*a. Normal aspect of a parotid gland. b, c. Parotid gland US in GS (b) and PD (c) modes, with the inhomogeneous aspect, with multiple hypoechoic areas, suggestive for glandular inflammation.*

*Musculoskeletal and Nerve Ultrasonography DOI: http://dx.doi.org/10.5772/intechopen.102640*


### **Table 6.**

*Ultrasound semiquantitative scoring system for parenchymal inhomogeneity by Salaffi et al. [60].*

### **3.7 Large vessel vasculitis**

Ultrasound imaging can detect signs of arterial involvement in giant cell arteritis and Takayasu disease. The characteristic US features of large vessel vasculitis include the presence of a hypoechoic swollen artery wall which is surrounded by oedema, known as the halo sign (**Figure 13**).

The use of US has been studied more extensively in giant cell arteritis. Detection of the typical patchy inflammation seen in temporal arteritis can benefit greatly from ultrasound examination. Besides wall thickening, large vessel vasculitis can display lack of compressibility, stenosis and vessel occlusion [6]. Importantly, giant cell arteritis can spare the temporal arteries in some cases, and thus US examination should also include other large vessels such as the axillary or carotid arteries. The diagnostic value of US has been highlighted by its adoption in the 2018 Update of the EULAR recommendations for the management of large vessel vasculitis. Ultrasound examination is included in the imaging tests used to confirm the diagnosis when large vessel vasculitis is suspected [62].

## **3.8 Muscular disease**

Various muscle pathologies can be assessed using ultrasonography. It can detect partial and complete muscle ruptures, fluid collections, muscle infarctions or development of muscle tumors. Features of posttraumatic lesions vary by severity. Milder intensity trauma leads to interstitial hemorrhage which appears as poorly defined hyperechoic areas. In more severe trauma, an intramuscular hematoma can develop, and echogenicity will vary based on time of lesions, with a visible muscle blunt, with a "bell tongue" aspect (**Figure 14**).

On US examination, normal muscle is slightly hypoechogenic with hyperechoic septa and fascia [17]. In transverse plane, muscle tissue will normally have a "starry night appearance", while in long axis fibers run parallel to each other and at an angle towards the muscle insertion. Patients with inflammatory myopathies, such as polymyositis, dermatomyositis and inclusion body myositis, will display changes in muscle echogenicity. In acute phases, muscle edema will cause thickening and only slight increase in echogenicity which proves reversible to treatment [63]. In later

### **Figure 14.**

*Ultrasonography of the pectoralis major muscle with a lesion. Asterisk – Effusion secondary to the hemorrhage, arrow – The pectoralis muscle blunt ("bell tongue" aspect).*

### **Figure 15.**

*Ultrasonography of the rectus femoris in a patient with polymyositis, that shows increased echogenicity and lack of the starry night appearance in GS mode (a), and decreased elasticity as showed by the blue color in elastography and the hardness percent (b).*

### *Musculoskeletal and Nerve Ultrasonography DOI: http://dx.doi.org/10.5772/intechopen.102640*

stages, ultrasound will detect markedly increased echogenicity, muscle atrophy and reduced elasticity (**Figure 15**).

Studies have observed correlations between US and histopathology and also significant changes in muscle stiffness when applying elastographic modalities. Patients with active myositis display increased stiffness and this will be gradually reduced as more severe muscle weakness develops [64].
