Non-Invasive Correlation of 18F-FLT PET and DW-MRI of Human Lung Carcinoma in a Xenograft Mouse Model

Lydia Wachsmuth¹, Sonja Schfers², Thomas Viel², Sven Hermann², Niclas Kremer², Michael Schfers², Klaus Schfers², Andreas H. Jacobs², Carsten Mller-Tidow³, Cornelius Faber¹

Diffusion-weighted magnetic resonance imaging (DW-MRI) and (18F-FLT) PET examinations were subsequently performed in a human lung carcinoma xenograft mouse model without change in animal position between scans in order to directly relate tracer accumulation to local diffusion coefficients. Tumor tissue heterogeneity was reflected by regional changes in ADC. Much higher 18F-FLT uptake in the proliferative rim of the tumor, showing low diffusion constants, compared to low radiotracer accumulation in the tumor core with high ADC values, support the assumption that high ADC values in the tumor core represent necrotic areas. Bimodal imaging findings were confirmed by immunohistochemistry.