BackgroundSystemic lupus erythematosus (SLE) is a rare autoimmune disease for which a population-based survey on the prevalence of the disease in South Korea has not yet been conducted. Our goal was to estimate the nationwide prevalence of SLE.MethodsThe International Classification of Diseases, Tenth Revision (ICD-10) code for SLE diagnosis—M32—was tentatively given when patients were suspected to have SLE before 2009. As such, the positive predictive value (PPV) of the M32 code shown in medical bills reflecting true SLE was uncertain. We attempted to estimate the prevalence of SLE in South Korea using national administrative database data from 2004–2006. We approximated the actual number of SLE patients by analyzing a list of SLE-coded patients provided by the National Health Insurance (NHI) and Health Insurance Review and Assessment Service. Prevalence was estimated by multiplying the PPV of the M32 diagnostic code by the number of patients receiving the code. The PPV was determined by three methods: direct investigation of the medical records of patients randomly selected from the SLE-coded patients list; assessment of all SLE patients treated at 56 selected hospitals in South Korea; and extrapolation from sub-groups at a single institute to the sub-groups of the national NHI data.ResultsThe estimated number of national SLE cases was between 9000 and 11 000, depending on the method of ascertainment, corresponding to a prevalence of 18.8–21.7 per 100 000 people.ConclusionsThis is the first report of a nationwide prevalence survey of SLE in South Korea. National databases may serve as a resource for epidemiologic studies of rare autoimmune diseases like SLE.

We annually evaluated (18)F-fluorodeoxyglucose-positron emission tomography/ computed tomography (FDG-PET/CT) scans for three consecutive years in a patient with rheumatoid arthritis. The inflammatory activity of the rheumatoid synovium was visualized in coronal and transverse sections by FDG-PET/CT. The extent and area of the synovial inflammation was relatively well delineated, and this technique was more informative in detecting inflammation than were conventional X-rays.

Recent technical advances in computed tomography (CT) and the introduction of three-dimensional (3D) image reconstruction through computer systems make distinct visualization of tiny defects in the hand and wrist a feasible task. Three wrists from three patients -- two of whom are patients with rheumatoid arthritis and one with osteoarthritis -- were evaluated by 3D CT. Images were obtained with a multidetector-row CT scanner. Bony wrist structures including erosions were observed in the patients with arthritis by means of 3D CT. 3D CT could clearly visualize bone-erosive lesions. It also revealed various interesting stereoscopic views of bony structures unattainable with conventional radiographic studies. 3D CT may serve to be interesting in future imaging studies in the rheumatology field.