Esophagus involvement in systemic sclerosis: ultrasound parameters and association with clinical manifestations

Background The esophagus involvement in systemic sclerosis (SSc) is very common yet underestimated due to the lack of suitable screening tools. This study aims to explore the usefulness of ultrasound (US) in the assessment of esophagus involvement and to identify its relationship with clinical and CT manifestations. Methods We performed transabdominal esophageal US in 38 SSc patients and 38 controls. US parameters including the abdominal esophagus length, esophagus wall thickness, shear-wave elastography, gastro-esophageal (His) angle, and reflux were compared. Relationships between distinguishable US parameters and clinical/CT parameters, such as gastro-esophageal reflux disease questionnaire (GERDQ), modified Rodnan skin score (mRSS), interstitial lung disease (ILD) score, the largest esophagus diameter (Dmax), and esophagus dilation percentage (%Eop), were evaluated. Results Abdominal esophagus length was shorter in the SSc group than the control group (2.69 cm vs 3.06 cm, P = 0.018), whereas His angle and the angle change before and after drinking water were larger in the SSc group than the control group (121° vs 108°, P < 0.001; 7.97° vs 2.92°, P = 0.025). Reflux was more frequently seen in the SSc group than the control group (7/38 vs 0/38; P = 0.017). As for correlation with clinical and CT parameters, His angle was higher in patients with GERDQ ≥ 8 than GERDQ < 8 (116.5° vs 125.6°, P = 0.035). Patients with reflux showed higher ILD score than patients without (15.8 vs 9.6, P = 0.043). Furthermore, abdominal esophagus length was negatively correlated with %Eop and Dmax ( r = − 0.573, P < 0.001; r = − 0.476, P = 0.003). Conclusion US parameters of the esophagus can distinguish SSc patients from controls, as well as have correlations with clinical and CT characteristics. Our pilot study first shows that US can be used as a noninvasive and convenient method to evaluate the esophagus involvement in SSc.