Dynamic Contrast Enhancement of Experimental Glioma: An Intra-individual Comparative Study to Assess the Optimal Time Delay

Abstract

The aim of this study was to compare tumor signal and contrast media uptake characteristics on contrast-enhanced T1-weighted sequences at 3 Tesla over 30 minutes after double-dose administration of different contrast agents in an animal model of brain glioma. Nine rats underwent magnetic resonance imaging (MRI) after stereotactic F98 glioma cell implantation before and repetitively for 30 minutes after injection of gadobutrol, gadopentetate, and gadobenate, respectively. Signal-to-noise ratio (SNR) and tumor contrast-to-noise ratio (CNR) were evaluated and MRI-derived tumor volumes were compared to histology. Postcontrast tumor SNR and CNR peaked at 4 minutes after contrast application. While contrast-enhancement within the tumor was fading, tumor volume increased by continuous contrast-uptake of peripheral parts between 4 minutes (137 + or - 29 mm(3), 126 + or - 16 mm(3), 141 + or - 24 mm(3)) and 20 minutes (182 + or - 35 mm(3), 164 + or - 32 mm(3), 191 + or - 25 mm(3)), respectively. At 8 and 12 minutes, 84% and 91% of the tumor volume were definable, respectively. Optimal correlation between MRI-derived tumor volume and histology is achieved by imaging up to 20 minutes after contrast application. At 4 minutes (this delay is mostly used in clinical routine), only 75% of the enhancing tumor volume is assessable. A delay of 8 minutes already reveals 84% of the tumor and seems to be a practical clinical compromise.