Systems and methods are provided for detecting collagen within tissue using magnetic resonance imaging. In some embodiments, pulse sequences are employed to measure signals at multiple TE values including ultra-short echo times, and the TE dependence of the measured signal is fitted to a mathematical function including at least two decay terms, where the first (initial) decay term is modulated and is associated with the presence of collagen. In another example embodiment, spectroscopy or spectroscopic imaging is employed to measure the free induction decay within at least one region of interest, and the time-dependence of the measured signal is fitted to a mathematical function including at least two decay terms, where the first decay term is modulated and is associated with the presence of collagen. In some embodiments, the methods described herein may be employed for the detection and/or assessment of myocardial fibrosis.