Blood Oxygenation Level-Dependent MRI of Cerebral Gliomas during Breath Holding

Purpose: To assess the cerebrovascular responses to short breath holding of cerebral gliomas using blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI). Materials and Methods: Six patients with a low-grade glioma and one patient with a high-grade glioma were studied using T2*-weighted echo planar imaging (EPI) during repeated periods of 15-second or 20-second breath-holding. Tumor vascularity was evaluated using dynamic susceptibility contrast perfusion MRI. Results: Increases in BOLD signal intensity during repeated breath-holding were consistently identified in patients' normal appearing gray matter, comparable with those in healthy adults. Absence of significant BOLD signal enhancement was noted both in low-grade and high-grade gliomas, which is either due to overwhelming hypoxia in a tumor, inadequacy or absence of hypercapnia-induced vasodilatation of tumor vessels, or both. Breath-hold regulated decreases in BOLD signals occurred only in the high-grade glioma, which is most likely due to the hypercapnia-induced steal effect that redistributes blood flow from tumor regions with unresponsive neovasculature to surrounding normal tissue. Conclusion: BOLD MRI during short breath holding can disclose differential cerebrovascular response between normal tissue and cerebral glioma.