Renal hypodense nodular shadow is commonly seen in CT and MRI findings and is an imaging description that usually suggests the possible presence of renal parenchymal lesions such as renal cysts. In clinical imaging, renal hypodense nodular shadow usually suggests the possible presence of nodular lesions within the kidney that are less dense than the renal parenchyma. The possible causes are localized renal lesions or fluid accumulation, etc., often suggesting the presence of lesions such as renal cysts or renal abscesses. In addition, renal hypodense nodular shadow may also be the manifestation of localized necrosis of the kidney, which is commonly caused by renal infarction leading to localized ischemia of the kidney, and thus necrosis. There may also be other causes of renal hypodense nodular shadow, it is recommended to go to the regular hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.