Radiography, MRI, CT, Bone Scan, and PET-CT

Imaging diagnosis of osteonecrosis (ON) uses various modalities such as plain radiograph, magnetic resonance imaging (MRI), computed tomography (CT), radionuclide examination, and positron emission tomography-computed tomography (PET-CT) [1, 2]. Plain radiograph and MRI are frequently used for diagnostic purposes during the examination. When unilateral osteonecrosis is shown on plain radiograph, radionuclide examination is used to determine whether there is involvement of the contralateral femoral head [3–6].