Value of Somatostatin Receptor Scintigraphy with 99mTc-HYNIC-TOC in Patients with Primary Sjögren Syndrome

Abstract

Objectives: Primary Sjögren syndrome (SS) is diagnosed based on the American European Consensus Group (AECG) criteria, but lacks specificity, not only in the involvement of salivary glands, but also in extra-glandular involvement. Whole-body somatostatin receptor scintigraphy with 99mTc-HYNIC-TOC scintigraphy could overcome these limitations. The aims of this study were to evaluate salivary gland uptake of 99mTc-HYNIC-TOC in untreated patients with de-novo diagnosis of SS as compared to control subjects and as compared to conventional sialoscintigraphy with 99mTcO4−. We also aimed to evaluate the involvement of joints. Methods: 99mTc-HYNIC-TOC was used with SS patients and uptake in joints and salivary glands was analyzed semi-quantitatively. Patients also underwent 99mTcO4 sialoscintigraphy. The control group that we analyzed consisted of 30 patients with neuroendocrine tumors. Results: Fifty-two females and 10 males fully met the AECG criteria for SS, and were included. A target background ratio (TBR) >1.18 in submandibular glands correctly classified 93% of the patients with SS in comparison to 27% for 99mTcO4 sialoscintigraphy. The area under the curve (ROC) analysis for TBR in submandibular glands was 0.95. In joints there was a huge variety in uptake. The median TBR was significantly higher in salivary glands in patients with SS compared to controls. Conclusions: 99mTc-HYNIC-TOC scintigraphy identified active inflammatory processes not only in the salivary glands, but, unexpectedly, also in many joints in patients with primary SS, contrary to popular belief. This technique provides an objective parameter to evaluate the inflammation burden in salivary glands and joints and could be used to evaluate response to treatment.

Physiological Biodistribution of ⁶⁸Ga-DOTA-TATE in Normal Subjects

“…Hence, 68 Ga-DOTA-TATE uptake was not recorded in the brain parenchyma. The salivary glands, including the parotid and submandibular glands, demonstrated diffuse and homogenous uptake of 68 Ga-DOTA-TATE, which is expected as Anzola et al ( 16 ) demonstrated that SSTRs are commonly expressed in the salivary glands.…”

Imaging in Primary Sjögren’s Syndrome

“…These receptors were shown to be overexpressed in various inflammatory and autoimmune diseases, and were found on, among others, activated lymphocytes, endothelial cells, and the monocyte lineage in synovium of rheumatoid arthritis (RA) patients [ 94 , 95 , 96 ]. Anzola et al [ 97 ] showed increased 99m Tc-HYNIC-TOC uptake within salivary glands of pSS patients compared to controls, as well as a considerably higher sensitivity of 99m Tc-HYNIC-TOC scintigraphy compared to conventional scintigraphy. Furthermore, they demonstrated that 99m Tc-HYNIC-TOC scintigraphy was able to identify joint involvement in a cohort of 62 pSS patients, of which many patients (87%) reported joint pain.…”

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

“…This was the subject of the Anzola [25] research whose results were published in 2019. In this study scintigraphy with 99m Tc-HYNIC-TOC as well as conventional sialoscintigraphy with 99m TcO4was performed on patients with de-novo diagnosis of pSS and control subjects.…”

“…In this study scintigraphy with 99m Tc-HYNIC-TOC as well as conventional sialoscintigraphy with 99m TcO4was performed on patients with de-novo diagnosis of pSS and control subjects. The examination made it possible to identify active inflammatory processes not only in the salivary glands of pSS patients, but also in the joints [25].…”