KCTD19 and male infertility: We performed Cr‐CEST by using 7T MRI on wild‐type C57B6/J mice and several types of male infertility models such as Sertoli‐cell only (SCO) (Kitw/Kitwv), maturation arrest (MA) (Zfp541 knockout mouse and Kctd19 knockout mouse), and teratozoospermia (Tbc1d21 knockout mouse).