Fig. 1

US images of small cell carcinoma of the bladder. a. Abdominal sonography revealed a hypoechoic mass in the apex of the urinary bladder. b. CDFI showed a rich blood flow signal inside this mass. c. CEUS imaging showed the mass began to undergo enhancement (wash-in time) from its periphery to its center at 10 s. d. CEUS imaging showed persistent high peak enhancement of the mass at 40 s. e. CEUS showed the enhancement signal of the mass was equal to the bladder wall at 120 s. f. Time-intensity curve showed wash-in time of 10 s, TTP of 33 s, SI of 62.7% and wash-out time > 60 s