CT examinations of the lower abdomen can include the colon and even the rectum, small intestine, and appendix; the urinary tract, such as the lower ureter and bladder, as well as the uterus and ovaries in female patients. In clinical practice, the most common diseases that are currently examined using CT of the lower abdomen mainly include acute suppurative appendicitis, and performing CT of the lower abdomen can indicate thickening of the appendix, and even fecal stones in the appendiceal cavity can be seen, and if a periappendiceal abscess is formed, a definite diagnosis can be made on CT. In addition, especially for colon or rectal cancer, further enhanced CT scan of the lower abdomen is usually performed to understand and clarify whether the lymph nodes around the mesentery are combined with metastatic cancer.