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 assessing 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 Blue infusion and histology the authors measured intracranial tumor volumes in a rodent brain tumor model (RT2) at days 10, 16 and 18 after implantation of cells 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 significant uptake of gadolinium and Evans Blue in the tumor suggesting a wide disruption of the blood-brain barrier.