Let $D$ be a Jordan domain in $\overline R^2$ and $\Gamma=\partial D$ be the boundary of $D$. Then $D$ is a quasidisk if and only if $\Gamma$ is a bounded circular distortion curve.
"Bounded circular distortion curves and quasidisks." Hokkaido Math. J. 34 (1) 97 - 101, February 2005. https://doi.org/10.14492/hokmj/1285766210