Analysis of FDG PET/CT imaging features of systemic lupus erythematosus

• Published in: The Journal of nuclear medicine (1978) Vol. 60
• Main Authors: Chen, Zi Wei, Wang, Qian
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.05.2019
• Subjects: Age; Blood; Bone marrow; Chronic conditions; Computed tomography; Connective tissue diseases; Connective tissues; Diagnosis; Diagnostic systems; Differential diagnosis; Effusion; Females; Hyperplasia; Inflammatory diseases; Juvenile rheumatoid arthritis; Lesions; Lupus; Lymph nodes; Lymphatic system; Males; Medical imaging; Nodes; Positron emission; Positron emission tomography; Quantitative analysis; Spleen; Splenomegaly; Systemic lupus erythematosus; Tibia; Tomography; Visual observation
• ISSN: 0161-5505; 1535-5667

Objectives: Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease involving multiple systems. Although there are corresponding diagnostic criteria, it needs to be differentiated from other connective tissue diseases when its clinical manifestations are not typical. Currently, the role of FDG PET/CT in the diagnosis of infection and non-infectious inflammation has been gradually recognized clinically. However, it has been found in clinical practice that the PET/CT manifestations of SLE are similar to Adult-onset Still's disease (AOSD). In this study, the FDG PET/CT images of the SLE patients and AOSD patients were compared to further analyze the imaging characteristics of SLE and its significance in the differential diagnosis. Methods: Among the subjects underwent PET/CT examination during April 2012 to June 2018, there were 22 patients (5 males and 17 females with a mean age of 50.6±20.1 years) diagnosed as active SLE and 43 patients (8 males and 35 females with a mean age of 41.8±15.0 years) diagnosed as AOSD. PET/CT images in the two groups were retrospectively analyzed, and 37 cases with negative PET/CT results in the same period were used as the control group (26 males and 11 females with a mean age of 51.9 ±9.9 years). The scan field of PET/CT was at least from the skull base to the middle of tibia, with both upper limbs placed on the sides of the body. Imaging characteristics of SLE was firstly observed by visual judgment and compared with the AOSD patients and control group, including the location and distribution of lesions. As a quantitative parameter, SUVmax was measured in each patient on spleen, bone marrow and blood pool, and compared between the different groups. Results: PET/CT findings were positive in all of the 22 SLE patients, which mainly presented as increased bone marrow diffuse FDG uptake (16), splenomegaly or diffuse increased FDG uptake in spleen (10), multiple reactive lymph nodes (8) and multi-serosal effusion (9). However, the above positive findings were all also can be seen in the AOSD patients, excepting the multi-serosal effusion is rare (p < 0.001). The results of semi-quantitative analysis showed that comparing with the control group, in SLE patients, SUVmax of the blood pool was reduced (1.6±0.4 vs 1.3±0.3, t=-4.010, p<,01), while SUVmax of the spleen (1.8±0.3 vs 2.3±0.7, t= 2.758, p=0.011) and bone marrow (2.3±0.5 vs 2.8±0.8, t= 2.699, p=0.011) were increased. However, in comparison with the AOSD patients, both of the spleen and bone marrow uptake in SLE patients were significantly lower than that in the AOSD patients (spleen SUVmax: 3.0±0.8 vs 2.3±0.7, t=-3.411, p=0.001; bone marrow SUVmax: 4.3±1.5 vs 2.8±0.8, t=-5.172, p<0.001). Conclusions: FDG PET/CT imaging in SLE patients is characterized by decreased FDG distribution in the blood pool, increased FDG uptake in the spleen and bone marrow, and multiple reactive hyperplasia of lymph nodes and multiple serous cavity effusion. Although these findings overlap with AOSD, semi-quantitative analysis is helpful for the differential diagnosis of the two.