The aim of the present study is to assess whether a new method of quantifying therapy-associated hemodynamic alterations based on DCE MR imaging may help to distinguish pseudoprogression from true progression in patients with high grade glioma, who received CCRT.

Combination temozolomide and radiation significantly prolongs survival compared with radiation alone and has become standard treatment for glioblastoma multiforme (GBM). Response assessment in GBM is difficult as a result of the frequent occurrence of early imaging changes indistinguishable from tumor progression, termed pseudoprogression. The majority of patients remain clinically stable. It is often unclear whether current therapy should be maintained or second-line therapy initiated. The incidence of pseudoprogression after concurrent chemoradiation is15%to 30%. A potential mechanism of pseudoprogression is that radiation-induced vascular changes may lead to focal transient increase in gadolinium enhancement. Dynamic contrast-enhanced (DCE) MR imaging provides a noninvasive means for quantifying tumor vascular properties.

Inclusion Criteria:

• Among the patients with high-grade glioma (glioblastoma multiforme or anaplastic astrocytoma), who received concurrent chemoradiation (CCRT) with temozolomide, the patients show the measurable enhancing portion (1 cm in the long diameter according to the RANO criteria) in the immediate f/up MRI after CCRT.

Exclusion Criteria:

• Among the patients with high-grade glioma (glioblastoma multiforme or anaplastic astrocytoma), who received concurrent chemoradiation (CCRT) with temozolomide, the patients do not show the measurable enhancing portion (1 cm in the long diameter according to the RANO criteria) in the immediate f/up MRI after CCRT.

Patients with high-grade glioma (glioblastoma multiforme or anaplastic astrocytoma), who receive concurrent chemoradiation (CCRT) with temozolomide