Dynamic MR imaging of neurohypophyseal germ cell tumors for differential diagnosis of infundibular diseases

Purpose: To investigate the MR dynamic patterns of neurohypophyseal germ ce ll tumors (GCTs) for differential diagnosis of infundibular diseases affect ing young people. Material and Methods: Eleven patients with neurohypophyseal GCTs underwent dynamic MR studies with T1-weighted spin-echo (SE) or turbo SE techniques. Other infundibular lesions, including adenohypophysitis (n=3), Langerhans' cell histiocytosis (LCH, n=2), and 1 hemangioblastoma from von Hippel-Linda u disease, were also evaluated. Serial images were obtained every 15 s (tur bo SE) or 30 s (SE technique) for 240 a after rapid injection of contrast m edium. The dynamic patterns were analyzed quantitatively with the contrast medium enhancement ratio. Results: On dynamic MR images, GCTs typically showed a gradual enhancement increase with a peak between 105 a and 180 s, while two showed a relatively rapid increase. LCH and hemangioblastoma showed a dynamic pattern similar to GCTs, while adenohypophysitis demonstrated a sharp rise and a steeper wa sh-out with an obvious peak before 90 s. Conclusion: Typical dynamic pattern of GCTs was the gradual enhancement inc rease without wash-out. Dynamic MR imaging can distinguish GCTs from adenoh ypophysitis, but is not useful for differentiation from LCH.