Renal artery stenosis and hypertension are very closely related. They can be mutually causal; they can also exacerbate each other. Hypertension in adolescents, especially in women, following an inflammatory response to fever is often caused by stenosis of the renal arteries in aortitis; a few middle-aged and elderly people with normal blood pressure can develop hypertension due to stenosis of the renal arteries. Many patients with hypertension, especially with diabetes and smoking, can develop renal artery sclerosis stenosis, which in turn aggravates hypertension. Whether to intervene in renal artery stenosis, first do renal imaging to see the function of both kidneys and their differences. The renal map is divided into segment a (blood supply segment for the kidney), segment b (absorption segment of the kidney), and segment c (excretion segment). The abc segment of the normal renogram is approximately equal in both kidneys (see Figure 1) Figure 1 The abc segment of the renogram is small in renal artery stenosis (see Figure 2) Figure 2 If ultrasound and renal arteriogram confirm renal artery stenosis on one side, and the renogram is small, you must see a vascular specialist for treatment.