Stamp LK, et al. - Researchers examined if monosodium urate (MSU), calcium pyrophosphate (CPP), and hydroxyapatite (HA) crystal deposits could be identified and be differentiated ex vivo using novel multi-energy spectral photon-counting computed tomography (SPCCT) imaging. A finger with a subcutaneous gouty tophus was imaged using plain x-ray, dual-energy CT, and multi-energy SPCCT. In addition, they obtained plain x-ray and multi-energy SPCCT images of a calcified knee meniscus. Outcomes demonstrate the utility of multi-energy SPCCT in detecting, differentiating, and quantifying MSU crystal deposits in a gouty finger ex vivo. Furthermore, these specifically detected, identified, and quantified CPP within an osteoarthritic meniscus, and distinguished them from HA crystal deposits. These findings support the potential value of multi-energy SPCCT in the diagnosis of crystal arthropathies.