Preclinical imaging is revolutionizing health-related research, expanding horizons in our knowledge at an unprecedented pace on human physiology, gene expression, physiopathology and disease evolution. Using imaging and transgenic small-animal models, disease progression can be monitored to evaluate candidate therapeutics, molecular tracers, and interventions. Preclinical positron emission tomography (PET) technology in particular is currently experiencing a rapid pace of innovation. Using novel detectors, systems are approaching the theoretical limits of resolution, with Full Field Accuracy and without compromise to sensitivity. Further, PET multimodal integration is evolving. Initial PET systems typically offered PET functional detections only. Later, PET/CT integration provided structural context, typically limited to skeletal anatomy and providing strictly static context. These integrations were relatively technologically direct, with negligible interference between PET and CT. PET/magnetic resonance imaging (MR) integration has been reported, though frequently with compromises in both PET and MR performance. It is only now, with recent advances in PET detector technologies, that truly uncompromised PET/MR integrations can be achieved, offering both sequential and even high field simultaneous data collection. These developments will deliver higher quality data and better physiological context than ever before. This article will highlight an advanced translational research preclinical imaging system for simultaneous PET/MR investigations in mice and rats. Read more.