Effect of Steroid on Brain Tumors and Surround Edemas : Observation with Regional Cerebral Blood Volume (rCBV) Maps of Perfusion MRI

Abstract

Purpose : To observe the hemodynamic change in brain tumors and peritumoral edemas

after steroid treatment, and then investigate the clinical usefulness of perfusion MRI.

Materials and Methods : We acquired conventional and perfusion MR images in 15

patients with various in tracranial tumors (4 glioblastoma multiformes, 4 meningiomas, 3 metastatic tumors, 1 anaplastic ependymoma, 1 anaplastic astrocytoma, 1

hemangioblastoma, and 1 pilocytic astrocytoma). For perfusion MR imaging, a 1.5T unit employing the gradient-echo EPI technique was used, and further perfusion MR images were obtained 2-10 days after intravenous steroid therapy. After processing of the raw data, regional cerebral blood volume (rCBV) maps were reconstructed. The maps were visually evaluated by comparing relative perfusion in brain tumors and peritumoral edemas with that in contralateral white matter. Objective evaluations were performed by

comparing the perfusion ratios of brain tumors and peritumoral edemas.

Result : Visual evaluations of rCBV maps, showed that in most brain tumors (67%,

10/15), perfusion was high before steroid treatment and showed in (80%, 12/15),

decreased afterwards. Objective evaluation, showed that in all brain tumors, perfusion

decreased. Visual evaluation of perfusion change in peritumoral edemas revealed change

in only one case, but objective evaluation indicated that perfusion decreased significantly in all seven cases.

Conclusions : rCBV maps acquired by perfusion MR imaging can provide hemodynamic

information about brain tumors and peritumoral edemas. Such maps could prove helpful in the preoperative planning of brain tumor surgery and the monitoring of steroid effects during conservative treatment.