MRI remains the gold standard in neuroimaging, but its high costs, large footprint, and infrastructure requirements limit deployment in many settings—including intensive care units (ICUs), emergency vehicles, and neonatal intensive care units (NICUs). These challenges demand portable, low-cost MRI systems specifically engineered for operation in space- and power-limited environments. Rather than adapting commercial scanners, our work focuses on the engineering design and prototyping of custom low-field MRI systems, using permanent magnets and compact hardware tailored to specific use cases. We hardware development with model-based reconstruction techniques to reduce system complexity and improve performance. This presentation will highlight several systems developed in our lab at the MGH Martinos Center—including a dedicated neonatal brain scanner—and will emphasize the technical and practical considerations involved in building accessible MRI from the ground up.