The goal of this study was to develop and validate a fast, robust and quantitative MRI method for the evaluation of lung water density, for the detection of pulmonary edema. Short lung T2* necessitates ultrashort TE (UTE) acquisitions. We propose a novel optimized UTE Yarn-Ball k-space trajectory that uses ~15% of the pure radial readouts arms required to achieve full sampling. Phantom studies validated accurate water density quantification. A dual-echo approach enabled automated lung tissue segmentation. An optimized Yarn-Ball k-space trajectory yields three-dimensional spin-density weighted lung water images (2.5mm isotropic resolution), without the need for breath-holding, in ~2 minutes.