“…For example, mEUS is not suitable for the evaluation of regional lymph node invasion, and mEUS cannot accurately differentiate between stages T3 and T4 because mEUS typically uses high frequency ultrasound, which limits the depth of penetration. In addition, according to previous studies, the accuracy of mEUS may decrease with increasing tumor size, advanced tumor stage, pedunculated-type tumors, villous lesions, and rectal tumors 4,13,25. Results can also be influenced by inadequate contact between the tumor and the probe due to air, stool, or irregular tumor surfaces, anatomic defects from previous biopsies or polypectomy, and peritumoral inflammation.…”