The double-line sign.
Zurlo
J V
JV
UMDNJ-New Jersey Medical School, Newark, USA.
D001842:Bone and Bones / Q000473:pathology; D005270:Femur Head / Q000473:pathology; D005271:Femur Head Necrosis / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D010020:Osteonecrosis / Q000175:diagnosis*