In order to detect and characterize metastases in preclinical studies, 3D T1 maps can be obtained with the MP2RAGE sequence. As high spatial resolution is required, the acquisition duration becomes prohibitive for the monitoring of metastases. Thus, acceleration via Compressed Sensing technique was achieved, necessitating a new undersampling scheme. T1 maps of the mouse whole brain were obtained in <1min. The T1 of brain metastases was not affected by CS acceleration. Then, ultra-high spatially resolved maps (130x125x141μm) were acquired without lengthening scan time, to detect early-growing metastases and accurately measure their volumes.