Evaluation of Rabbit VX2 Tumor Model Using Magnetic Resonance T1-Mapping and T2-Mapping Techniques at 1.5T
Most routine magnetic resonance imaging only investigates morphology differences between normal and abnormal tissues. Magnetic resonance T1 and T2 relaxation times are important indices for evaluating pathological changes in tissue. T1-mapping and T2-mapping techniques can be used to perform quantitative analysis as well as qualitative analysis of tissue characteristics. This study aimed to perform long-term monitoring of the VX2 tumor progression and distribution on New Zealand rabbit thigh tissue using three dimensional T1-weighted (T1W) sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE), T2-weighted (T2W) SPACE, T1-mapping and T2-mapping techniques. The signal intensity (SI), T1 and T2 relaxation times of normal muscle and VX2 tumor were measured to evaluate the tumor characteristics. The nonparametric Mann–Whitney U test results showed that there were significant differences in SIs of T1W SPACE images, SIs of T2W SPACE images, T1 relaxation time and T2 relaxation time at the same day after VX2 implantation between normal tissue and VX2 tumor (p values < 0.05). There were also significant differences in time course average values of SIs of T1W SPACE images, SIs of T2W SPACE images, T1 relaxation time and T2 relaxation time between normal tissue and VX2 tumor (p values < 0.05). T2W SPACE, T1 mapping and T2 mapping were superior to T1W SPACE in the early detection of VX2 tumor. T1 mapping and T2 mapping techniques could be used to evaluate tumor growth and metastasis. T1 and T2 maps might be referenced as biomarkers and predictive indices in the evolution of pathologies.