Fig. 2

a 5–10 s of injected contrast agent microbubbles of contrast agent reached the interlobular arteries and arcuate arteries; b 10–15 s the renal cortex began to develop and gradually enhanced, and the renal medulla did not develop; c renal medulla was developed and gradually enhanced after 25 s; d it began to gradually fade after about 1 min and lasted for about 3–6 min. The above images were derived from our own patients which was approved and agreed the requirement for informed consent by the institutional review board of Peking Union Medical College Hospital (approval number, I-23PJ1284)