Optimal detection of targeted paramagnetic molecular probes in vivo by MRI rely on multiple factors. Largely the optimization of its chemical and biophysical characteristics, interaction with the desired target, biodistribution, etc. In this talk we will introduce a clinical case to emphasize the use case of a targeted molecular probe and discuss the key aspects for detection from an applications perspective. We will introduce and compare a variety of molecular probes that have proven successful at detecting a target in vivo. Furthermore, this talk will tie in considerations for clinical applications and the path to translation.