The rat tail sign is a manifestation of imaging. The presence of the rat tail sign in different areas can be associated with different diseases.
For example, a rat tail sign on examination of the biliary system, where the distal end of the dilated biliary system is narrowed by cancerous tissue infiltration, making the lumen inner diameter narrow or tissue extending from both ends of the tumor, shows rat tail-like changes on imaging, as seen in bile duct cancer. Further examination of the upper abdomen with enhanced CT or magnetic resonance imaging of the pancreatic bile duct can be performed. Surgical treatment can be performed after diagnosis.
When there is a rat tail sign on CT examination of the lung, the possibility of lung cancer is mostly considered. It is usually the infiltration of cancer tissue along the longitudinal axis of the bronchus that spreads, causing a narrow irregular defect to form at the end of the bronchus, forming the rat tail sign. Early stage of lung cancer can be treated by surgery to remove the lesion. In advanced stages of lung cancer, multiple metastases can be treated conservatively, combined with targeted drug therapy or radiotherapy.
The rat tail sign can also be seen in esophageal cancer.
When the rat tail sign is present on imaging, it is important to further refine the relevant tests to detect the disease early and treat it aggressively.