Fig. 4

Convoluted and expanded tubular structures were found in both sides of the uterine bodies. An internal exploration of the tubular structures and the frequency spectrum of high-speed and low-resistance arteries and veins showed that the blood-supply artery came from the internal iliac artery branch. Multiple hyperechoic areas were identified in the left side of the uterine body (suggesting the spring ring), followed by a comet-tail sign with no obvious blood-flow signal found at the spring ring