Reply to "Matters Arising: a simple method for diagnosing gallbladder malignant tumors with subserosa invasion by endoscopic ultrasonography".

The reader noted that a deep hypoechoic area is the main echoic indication of subserosa (SS) invasion of malignant gallbladder tumors. In this study, we evaluated an irregular lateral high-echoic layer (LHEL) as the main indication of SS invasion. If the presence of a deep hypoechoic area combined with an irregular LHEL is considered, the diagnosis of SS invasion may be improved.