Investigation of the BOLD Response to Carbogen Breathing with Tumour Blood Volume in an Intracranial F98 Rodent Glioma Model

Efthymia Papaevangelou¹, Kirstie Suzanne Opstad¹, Franklyn Arron Howe¹

Tumour vascularity and oxygenation was investigated using blood oxygenation level dependant (BOLD) MRI in orthotopic F98 gliomas. Fractional blood volume (fBV), measured using a USPIO contrast agent, was compared with a carbogen-induced BOLD response. In tumour regions, with wide ranging fBV, a strong correlation was found between ΔR₂* and fBV. Normal-appearing contralateral brain had lower fBV and a larger R₂* response than non-tumour bearing normal brain. Low fBV may be an effect of vascular compression by the tumour and alter interpretation of the tumour BOLD response. fBV appears a dominant factor determining the size of BOLD response in this model.