Evaluation of ulcerative colitis activity using transabdominal ultrasound shear wave elastography

Background: Transabdominal ultrasound (US) has been reported to be effective in the evaluation of ulcerative colitis (UC). US can measure shear wave elastography (SWE) and shear wave dispersion (SWD), which may be correlated with inflammation and necrosis. We aimed to investigate the relationship between UC activity and SWE and SWD. Methods: Patients with UC who underwent US within 2 days before or after a colonoscopy between April 2019 and March 2020 were included. SWE and SWD were measured in the sigmoid colon; the correlations of SWE and SWD with the Lichtiger index and the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) were investigated. We also compared SWE and SWD between patients with mucosal healing and those in the active phase according to the UCEIS. Results: Twenty-six UC patients were enrolled. The median Lichtiger index, UCEIS, SWE values, and SWD values were 8 [interquartile range (IQR), 5.3–10.8], 4 (IQR, 3.3–5), 1.69 (IQR, 1.49–2.16) m/s, and 11.9 (IQR, 10.9–13.3) (m/s)/kHz, respectively. The Lichtiger index and UCEIS were negatively correlated with the SWE values (rs=−0.404 and rs=−0.506) but not with the SWD values (rs=0.004 and rs=0.002). The SWE values differed significantly between the mucosal healing and active phase groups [2.40 (IQR, 2.18–3.38) vs. 1.62 (IQR, 1.44–1.95) m/s, P=0.007], whereas the SWD values did not [13.1 (IQR, 7.05–21.6) vs. 11.9 (IQR, 11.1–13.2) (m/s)/kHz, P=0.918]. Conclusions: SWE may be useful for the evaluation of UC activity and could be a noninvasive method of assessing disease severity.