Determination of intracranial tumor volumes in a rodent brain using magnetic resonance imaging, Evans Blue, and histology: A comparative study

The measurement of tumor volumes is a practical and objective method of ass essing the efficacy of a therapeutic agent. However, the relative accuracy of different methods of assessing tumor volume has been unclear. Using T-1- weighted, gadolinium-enhanced magnetic resonance Imaging (T-1-MRI), Evans B lue infusion and histology we measured intracranial tumor volumes in a rode nt brain tumor model (RT2) at days 10, 16 and 18 after implantation of cell s in the caudate putamen. There is a good correlation between tumor volumes comparing T-1-MRI and Evans Blue (r(2) = 0.99), T-1-MRI and Histology (r(2 ) = 0.98) and histology and Evans Blue (r(2) = 0.93). Each of these methods is reliable in estimating tumor volumes in laboratory animals. There was s ignificant uptake of gadolinium and Evans Blue in the tumor suggesting a wi de disruption of the blood-brain barrier.