Intravenous cholescintigraphy using Tc-99m-labeled agents in the diagnosis of choledochal cyst.

Twelve patients with choledochal cyst have undergone intravenous radionuclide cholescintigraphy (IVRC) with Tc-99m-labeled HIDA or PG before surgery. The most characteristic findings are: (1) A round or ovoid photon-deficient area in the region of the gallbladder in the early images; (2) progressive accumulation of radioactivity in the same region in later images, especially at 2 hr after injection; (3) the long axis of this particular area directed downward and to the patient's left from the right midclavicular line, suggesting the direction of the common bile duct; and (4) persistent pooling of the tracer up to 24 hr, even after a fatty meal. By these criteria, correct diagnoses have been made preoperatively in ten of 12 cases (83.3%). We conclude that IVRC using Tc-99m HIDA or Tc-99m PG is an excellent first-line diagnostic tool for choledochal cyst.