Definitive diagnosis of choledochal cyst by 99mTc-pyridoxylideneglutamate sequential scintiphotography.

Sequential supine scintiphotography of the abdomen was performed after intravenous administration of 99mTc-pyridoxylideneglutamate (99mTc-PG) to verify the presence of choledochal cyst in an 18-month-old boy who presented with a mass in the right upper quadrant of the abdomen. The total body radioactivity effect, which is similar to the total body opacification during intravenous cholangiography or urography, was clearly demonstrated as a cold area corresponding to the cyst and assisted in the diagnosis. The specific finding was sequential filling of the gallbladder and cyst. In view of the relatively low radiation dose and good physical characteristics of 99mTc for imaging, 99mTc-PG sequential scintiphotography is useful for the definitive preoperative diagnosis of choledochal cyst in infants and children.