Focal Myositis of the Leg Presenting as Fever of Unknown Origin Detected by FDG PET/CT

PET/Computed Tomography in the Evaluation of Fever of Unknown Origin and Infectious/Inflammatory Disease in Pediatric Patients

Fever in children is common. If it persists and its cause cannot be identified in a reasonable time, along with laboratory and conventional imaging investigations, it is defined as fever of unknown origin (FUO). 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) is well established in the evaluation of malignancy, which is a possible cause of FUO. FDG often locates inflammatory and infectious lesions considered nonspecific or false-positive for oncology; however, these findings are beneficial in FUO evaluation because infectious and inflammatory diseases are important FUO causes. FDG-PET/CT is being increasingly used for investigation of FUO as well as infectious/inflammatory disease.

PET Scan: Nuclear Medicine Imaging in Myositis

PURPOSE OF REVIEW

Positron emission tomography (PET) combined with computed tomography (CT) has proven useful as a cancer screening technique in patients with inflammatory myopathy, mainly dermatomyositis. In this review, we focus on advances in this direction and other potential applications of PET/CT in patients with inflammatory myopathy.

RECENT FINDINGS

Cancer screening by PET/CT seems suitable and cost-effective in patients with myositis. It has also shown value as a hybrid technique for diagnosing myositis versus controls and could be of interest for differentiating between polymyositis and sporadic inclusion body myositis. Quantification of muscle activity by PET/CT seems reliable. Preliminary data suggest that it could also be used to diagnose and measure the activity of the disease in the lung. PET/CT should be in the toolbox of physicians managing patients with myositis. The multiple applications of PET/CT include its value for cancer screening, measuring the activity of the disease in muscle, and helping to differentiate between myositis phenotypes. The possibility to diagnose and monitor inflammatory lung activity remains to be demonstrated in well-designed studies.