Use of positron emission tomography scanning to evaluate pseudoresponse

Although an important part of the neuro-oncologists armamentarium, antiangiogenic chemotherapeutic agents can result in a pseudoresponse. This phenomenon occurs because the contrast enhancement that is used to measure tumor burden radiographically, depends upon the breakdown of the blood-brain barrier which may be restored after treatment with antiangiogenic agents, even without true eradication of the neoplasm. This occurrence may complicate attempts to determine an accurate prognosis for patients with malignant brain tumors as well as delay the initiation of more beneficial treatment strategies.