Fig. 2.

“Whirlpool sign” of spermatic cord. a Gray-scale transverse US image of upper left scrotal sac shows an eddy swirl (arrow) of the spermatic cord suggesting torsion of the cord. This 12-year-old boy woke with acute left testicular pain and experienced nausea and vomiting along with the pain. b Power Doppler US image of the same twisted cord shows concentric pattern of preserved flow in the vessels of the twisted cord. The flow in the left testis (not shown) was minimally decreased compared to the right side and bilateral bell clapper deformity was found during orchiopexy along with complete torsion of the left testis with 360° twist. c Gray-scale longitudinal US image of the left scrotum in a 13-year-old boy with 1 day of left-side pain shows abrupt spiral twisting of the spermatic cord (arrow) at the external inguinal ring, creating a whirlpool sign. d Color Doppler transverse image of the testes in the same boy as in (c) shows preserved and symmetrical flow bilaterally. After manual detorsion in the emergency room, he underwent orchiopexy and was diagnosed with intermittent torsion