Comment on: Muscle fluorodeoxyglucose uptake assessed by positron emission tomography-computed tomography as a biomarker of inflammatory myopathies disease activity: reply

The Role of Quantitative and Semi-quantitative [18F]FDG-PET/CT Indices for Evaluating Disease Activity and Management of Patients With Dermatomyositis and Polymyositis

“…Although there is evidence that [ 18 F]FDG is an overall suitable modality to assess disease activity in IIM, few data exists on its usefulness to monitor disease activity over time. The largest evidence could be derived from the study by Matuszak et al (23) who showed changes in [ 18 F]FDG uptake at consecutive time points in 10 patients using the muscle SUVmax/liver SUVmean ratio which correlated well with the clinical muscle disease activity. Finally, though magnetic resonance imaging remains the most widely used technique evaluate muscle activity in daily practice, the major question remains if [ 18 F]FDG-PET/CT (given its current lack of standardized interpretation criteria) has any possible advantage over MRI in assessing disease activity (35).…”

“…The database search identified 252 records found and 236 records were excluded after title/abstract screening and full-text content because those did not provide any relevant information on the topic of this review (Figure 1). Sixteen articles were eligible for a more detailed description in this review (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31).…”

“…A direct comparison between SUVmax and SUVmean values demonstrated a slightly better diagnostic accuracy using a SUVmax cut-off value. Two studies used a ratio of SUV's with liver uptake as reference with optimal cut-off values of 0.45 and 0.66 yielding a sensitivity of 75% and 92% and a specificity of 100 and 89%, respectively (18,23). The study by Martis et al (25), evaluating the ratio of muscle uptake in limbs compared to the muscle uptake in the lumbar region, reported a moderate diagnostic accuracy with sensitivity of 50% and specificity of 83% using a cut-off value of 1.73.…”

Radiological Characteristics of Patients With Anti-MDA5–Antibody-Positive Dermatomyositis in 18F-FDG PET/CT: A Pilot Study

“…PET/CT was usually performed to screen malignancy in the patients with IIM (11). Moreover, abnormal increases in 18 F-FDG uptake on the PET/CT images were observed in proximal muscles, which are correlated to inflammatory lesions in the patients with IIM (12,13). A good correlation was also found between the maximal 18 F-FDG standardized uptake value (SUVmax) and the results of muscle biopsy in the patients with myositis patients (14).…”