Diagnostic Perspectives in Bone and Soft Tissue Infections

Musculoskeletal (MSK) infections encompass acute and chronic osteomyelitis, subacute lesions and soft tissue infections, including cellulitis, pyomyositis, abscesses, tenosynovitis, septic bursitis and necrotising fasciitis. Early recognition is critical, as clinical findings may be nonspecific and delayed diagnosis can result in deformity, chronic sinus tracts or sepsis. Imaging is pivotal for diagnosis and management. Radiographs are first-line but often detect late changes. Computed tomography (CT) is valuable for cortical destruction, sequestra, and gas. Magnetic resonance imaging (MRI) is highly sensitive for marrow and soft tissue involvement. Key imaging clues improve diagnostic confidence: The penumbra sign in Brodie’s abscess, the ghost sign in diabetic foot osteomyelitis, and paradiscal marrow involvement with smooth-walled paravertebral abscesses in spinal tuberculosis (TB). Nuclear medicine and fluorodeoxyglucose positron emission tomography/CT (FDG PET/CT) complement structural imaging in detecting active disease and monitoring therapy. Soft tissue infections require a multimodal approach. Ultrasound (US) rapidly detects superficial collections and guides drainage. CT delineates fascial thickening, gas and deep abscesses. MRI precisely defines muscular, fascial and tendon involvement, allowing accurate characterisation of cellulitis, pyomyositis, abscesses, tenosynovitis and necrotising fasciitis, while detecting joint or bone extension. This article provides a concise overview of imaging in MSK infections, highlighting diagnostic pearls that enhance accuracy and guide timely management.