The Utility of Tc-99m Hydroxydiphosphonate Single-Photon Emission Computed Tomography/Computed Tomography in Symptomatic Kohler's Disease.

Kohler's disease (KD) is a rare disorder of the foot in children where there is avascular necrosis of the navicular bone (NB). It presents with pain and limping and is often misdiagnosed as an infection. However, by adding single-photon emission computed tomography-computed tomography (SPECT-CT) of the foot, the lesion is localized to the NB, leading to the diagnosis of KD. We report the case of a 6-year-old boy with limping and foot pain, who underwent a bone scan using Tc-99m hydroxydiphosphonate and SPECT-CT of the feet. SPECT-CT was necessary not only to localize the exact site of the pathology in an area with small bones but also to confidently reach the diagnosis of KD and proceed with the correct management plan.