Provided are methods and systems for detecting a maturing arterio-venous fistula comprising a vein. An exemplary method comprises determining a wall thickness of the fistula and a lumen diameter of the fistula vein using a high frequency ultrasound imaging system. A blood pressure of the subject is determined. A circumferential vessel wall stress is determined from the measured blood pressure, the wall thickness of the fistula and a determined radius of the measured diameter of the fistula. The determined circumferential vessel stress is compared to a predetermined threshold stress to determine if the fistula is mature.