Ultrasound Imaging of Quadriceps Muscle in Patients With Knee Osteoarthritis

Ultrasound assessment was performed on rectus femoris (RF), vastus intermedius (VI), vastus medialis (VM) and vastus lateralis (VL) muscles using with an ultrasound-imaging device (Philips Medical Systems EPIQ 5 Release 5.0.2, Amsterdam).

All images were analysed using the Image J software (Version 1.48v, National Institutes of Health, Bethesda, MD, USA) by two different analysers (five years and one-year of experience in US image analysis).