Imaging beyond muscle magnetic resonance imaging in inclusion body myositis

Diagnosis of inclusion body myositis (IBM), the most common acquired mus-cle disorder in adults above the age of 40, remains dependent on demonstra-tion of the classic clinical phenotype and confirmed by muscle histopathological examination. The European Neuromus-cular Centre (ENMC) 2011 diagnostic criteria for the diagnosis of IBM in-cludes the demonstration of one or more of the muscle pathological findings - in-flammation, vacuolation or protein ag-gregation. Muscle biopsy is an invasive procedure and patients often require more than one biopsy to establish a de-finitive diagnosis of IBM. Over the past few years, there has been considerable gain in knowledge regarding various imaging modalities that may comple-ment the diagnosis of IBM, and in some cases have the potential to obviate the need for more invasive procedures, such as muscle biopsy. Positron emission to-mography (PET) using different ligands may serve as a surrogate biomarker of therapeutic target engagement in IBM. This review concentrates on a critical evaluation of the literature looking at the utility of muscle ultrasound, dual energy x-ray absorptiometry (DEXA), and positron emission tomography and their role in IBM.