Variation in Attenuation in L1 Trabecular Bone at Different Tube Voltages: Caution Is Warranted When Screening for Osteoporosis With the Use of Opportunistic CT - Garner, H W; Paturzo, M M; Gaudier, G; Pickhardt, P J; Wessell, D E (AJR Am J Roentgenol, 2017)