Current Status of Bone Single-Photon Emission Computed Tomography Combined with Computed Tomography in Evaluation of Foot and Ankle Pain

Abstract

The complex anatomy of the foot and ankle makes it a clinical challenge to reach a final diagnosis in patients with foot and ankle pain. Conventional imaging modalities such as radiography, computed tomography (CT), and magnetic resonance imaging (MRI) play a vital role in making a diagnosis in patients with foot and ankle pain. MRI is considered to be the go-to modality for foot and ankle pathologies, but it has limitations in patients with metallic implants and claustrophobia. With wider availability and excellent imaging quality of new-age gamma cameras, bone single-photon emission computed tomography combined with CT (SPECT/CT) with technetium-99m (99mTc) labeled bisphosphonates has come into forefront for diagnosis of foot and ankle pathologies. SPECT is known to have high sensitivity to detect lesions but with low specificity. This low specificity was overcome by the introduction of SPECT/CT, a hybrid imaging modality that involves anatomical correlation of CT with the functional imaging of SPECT. SPECT/CT is extremely useful for evaluating the common but challenging causes of foot and ankle pain such as osteoarthritis, impingement syndrome, infection, inflammation for detecting optimal sites for intraarticular injection, and evaluation of diabetic foot. This review article aims to discuss various imaging modalities available for foot and ankle evaluation and the current status of SPECT/CT in diagnosing various foot and ankle pathologies.