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

PURPOSE: To investigate the MR dynamic patterns of neurohypophyseal germ cell tumors (GCTs) for differential diagnosis of infundibular diseases affecting young people.

MATERIAL AND

METHODS

Eleven patients with neurohypophyseal GCTs underwent dynamic MR studies with Tl-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-Lindau disease, were also evaluated. Serial images were obtained every 15 s (turbo SE) or 30 s (SE technique) for 240 s after rapid injection of contrast medium. 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 s 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 wash-out with an obvious peak before 90 s.

CONCLUSION

Typical dynamic pattern of GCTs was the gradual enhancement increase without wash-out. Dynamic MR imaging can distinguish GCTs from adenohypophysitis, but is not useful for differentiation from LCH.