Appendiceal thickening is mainly due to appendiceal wall congestion, which is mainly caused by inflammatory stimulation. The appendix is the blind end of the human appendix, which is normally no more than 1 cm in diameter and about 3-4 cm in length. The lumen of the appendix contains a large number of inflammatory cells and lymphocytic follicles, which can become hyperplastic when bacteria or viruses invade the appendix. In addition, when the appendix is obstructed by a fecal stone, the whole appendix wall will become ischemic necrosis, and the appendix wall will be heavily edematous to form inflammatory manifestations, which is also one of the causes of appendiceal thickening.