Disease activity and response to therapy monitored by [18F]FDG PET/CT using volume-based indices in IgG4-related disease

Abstract

Purpose The efficiency of [18F]FDG PET/CT using volume-based indices was evaluated to assess the disease activity and response to therapy in patients with immunoglobulin G4-related disease (IgG4-RD). Methods A total of 17 patients with IgG4-RD were examined with [18F]FDG PET/CT before and during treatment. The lesion boundary was determined using a fixed threshold of standardized uptake value (SUV) ≥ 2.5. The highest maximum SUV (SUVmax) among all affected lesions was calculated for individual patients. We summed metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of each affected lesion to generate a total MTV and total TLG. PET results were compared with those of serum IgG4 and soluble interleukin-2 receptor (sIL-2R) levels. Results The mean number of involved organs per patient was 3.8 as determined by [18F]FDG uptake. The number of involved organs, total MTV and total TLG were significantly correlated with IgG4 (P = 0.046, < 0.001, < 0.001, respectively) and sIL-2R (P < 0.001, = 0.031, 0.031, respectively). According to the clinical assessments for therapy response, all patients were classified as improved. The SUVmax, total MTV, and total TLG during therapy were all significantly lower than those before therapy (all P < 0.001). Conclusion [18F]FDG PET/CT is valuable for assessing the extent of multi-organ involvement before therapy and monitoring subsequent therapy in patients with IgG4-RD. [18F]FDG PET/CT using volumetric indices correlated with serum IgG4 and sIL-2R levels.

18F-fluorodeoxyglucose PET and PET/computed tomography for the evaluation of immunoglobulin G4-related disease: a systematic review

“…Partially, in contrast, the number of involved organs, MTV and TLG demonstrated a significant correlation with IgG4 and also soluble interleukin-2 receptor (sIL-2R) levels in other studies [17,28]. Furthermore, when available IgG4 levels decrease under treatment in concordance with PET/CT results [13].…”

“…Partially, in contrast, Mitamura et al . [28] reported a correlation between the number of involved organs, total MTV and total TLG with IgG4 and sIL-2R levels. Furthermore, a correlation between sIL2-R and TLG and with SUVmax, but not with IgG4 levels, was reported by Nakatsuka et al .…”

“…Hybrid 18 F-FDG PET/CT imaging is also a valuable tool for the assessment of treatment response and disease activity in IgG4RD. When effective, therapy results in statistically significant reduction in the number of organs involved by disease and in sites of tracer uptake [12,13,15–17,23,25–28,34]. Furthermore, PET/CT semiquantitative parameters such as SUVmax, SUV mean, MTV and TLG could play a role for the evaluation of treatment response given their significant decrease after effective therapy [16,23,28,34].…”

AuntMinnie fluorodeoxyglucose positron emission tomography-computed tomography leads to diagnosis of immunoglobulin G4-related disease

“…[ 2 3 ] The commonly affected organs include the pancreas, pancreatobiliary tract, lacrimal gland, salivary gland, lung, retroperitoneal region, lymph nodes, and kidneys. [ 4 5 ] However, virtually any organ can be involved. IgG4-RD is therefore considered a multiorgan systemic disease.…”

Renal Involvement of Immunoglobulin G4–Related Disease Presenting as a Solitary Hypermetabolic Mass Mimicking Renal Tumor on 18F-FDG PET/CT

“…Immunoglobulin G4-related disease is a systematic autoimmune disorder typically affecting the pancreas, bile duct, orbital tissues, salivary glands, kidneys, and retroperitoneum, 1,2 usually with increased FDG activity. 3 Diagnosis of IgG4-related disease with 18 F-FDG PET/CT is always based on coexistence of multiorgan involvement, such as salivary gland, lacrimal gland, pancreas, and bile duct. 4,5 Immunoglobulin G4-related renal disease most commonly manifests as tubulointerstitial nephritis or membranous nephropathy, 6 which are generally unremarkable in conventional imaging.…”