Currently the two imaging techniques used to

Currently, the two imaging techniques used to diagnose damage to salivary glands after RAI therapy are scintigraphy and sialography. [Tc]Pertechnetate salivary scintigraphy plays a vital role in evaluating parenchymal damage to these glands (Caglar et al. 2002; Raza et al. 2006; Solans et al. 2001). Reduced Tc uptake by the glands, usually developing more than 1 y post-operatively, indicates that the salivary aminopeptidase inhibitor is undergoing fibrosis (Caglar et al. 2002; Raza et al. 2006; Solans et al. 2001). Sialography allows evaluation of the ductal system of the glands. Ultrasonography (US) is seldom used, although the technique is both easy and non-invasive (Brozzi et al. 2013; Gritzmann et al. 2003).
Acoustic structure quantification (ASQ) software is used to analyze the statistical features of ultrasonographic echoes, and has recently performed well for the quantitative assessment of liver echogenicity. Several studies reported that ASQ is useful for detecting and quantifying structural changes in diffuse liver disease (Toyoda et al. 2009; Tuthill et al. 1988; Yamada et al. 2006). Recently, there have been attempts to evaluate the thyroid gland using ASQ (Rhee et al. 2015; Zandieh et al. 2016). ASQ makes possible to differentiate tissue types and detect structural changes in the tissue parenchyma by examining the speckle pattern in a selected region of interest (ROI). However, to date, no study has explored salivary gland echogenicity using this tool.


The demographic and clinical characteristics of the three groups are summarized in Tables 1 and 2. A total of 63 patients had been treated with 131I: 43 asymptomatic RAI-treated patients with 120.5 ± 44.55 mCi (30–180 mCi) and 20 chronic RS patients with 136.84 ± 22.31 mCi (130–180 mCi) (p = 0.004) (Table 1). RAI therapy was used for remnant ablation after thyroid surgery and/or to treat metastases. Symptom score was significantly higher in the patients with chronic RS (5.26 ± 2.08) than in the asymptomatic RAI-treated patients (0.1 ± 0.61) (p < 0.001). Time since the last RAI treatment was 42.26 ± 32.74 mo for the asymptomatic RAI group and 35.9 ± 26.41 mo for the RS group (p = 0.737) (Table 1). A total of 33 control patients without any clinical symptoms or history of salivary disease underwent neck US, which revealed normal salivary parenchymal echogenicity; homogeneous echotexture and echogenicity similar to cell cycle of the thyroid gland (Bruneton and Mourou 1993). No patient was on medication affecting the salivary glands.
The mean age of the asymptomatic RAI therapy group (51.58 ± 11.52 y) was higher than that of the chronic RS (47.4 ± 12.6 y) and control (42.58 ± 12.24 y) groups (p < 0.001). No gender bias was evident in the normal control group, but females predominated in the treated groups (p < 0.001) (Table 2). The volumes of both the parotid and submandibular glands of patients who had undergone RAI therapy, including the asymptomatic RAI-treated group and the chronic RS group, were less than those of normal glands (Table 3). The ASQ values for each group are summarized in Table 3. All ASQ parameters of asymptomatic patients or patients with RS who had undergone RAI therapy were significantly greater than those of patients with normal salivary glands for both the parotid and submandibular glands (p ≤ 0.001) (Figs. 1 and 2). Among the ASQ values, we calculated the post hoc power of the study using the mode and average for the parotid glands, representatively. In a one-way ANOVA test, sample sizes of 66, 86 and 40 were obtained from the three groups whose means were to be compared. The total sample of 192 patients achieved 72.38% power to detect differences among the parotid gland mode values and 96.03% power to detect differences among the parotid gland average values with a 0.05 significance level.