T1ρ and T2 mapping detect acute ischemic injury in a piglet model of Legg-Calvé-Perthes disease. - Johnson CP; Tóth F; Carlson CS; Armstrong AR; Zbýň Š; Wu B; Ellermann JM; Kim HKW (Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2022)