Department of Immunology and Rheumatology, Division of Advanced Preventive Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Department of Rheumatology, National Hospital Organization Nagasaki Medical Center, Omura, Japan.
Clin Exp Rheumatol. 2021 Nov-Dec;39(6):1338-1344. doi: 10.55563/clinexprheumatol/bsrhey. Epub 2021 Jan 28.
To investigate the utility of 18F-FDG PET/CT in the diagnostic procedure of IgG4-related disease (IgG4-RD), we analysed the association between quantitative method of 18F-FDG PET/CT and histological findings.
Twenty-one patients with IgG4-RD in whom 18F-FDG PET/CT was performed at the time of diagnosis were enrolled. Tissue biopsy was performed at 24 sites in 21 patients. To perform quantitative analysis of 18F-FDG PET/CT imaging, the highest standardised uptake value (SUV) of the pixels (SUVmax) and the average SUV (SUVmean) within the biopsied lesion were measured. The SUVmean of the liver was also measured as a reference.
The mean age at diagnosis was 64.6±11.9 years, and the median serum IgG4 level was 650 mg/dl. Histological findings were consistent with IgG4-RD (histopathology-positive) at 19 out of 24 sites. Although there was no significant difference in the values of SUVmax between histopathology-positive and histopathology-negative tissues, the values of SUVmean were significantly higher in the histopathology-positive tissue (4.98 and 3.54, respectively p<0.05). The values of SUVmean/liver were also higher in the histopathology-positive tissue (2.17 and 1.52, respectively p<0.05). To establish a cut-off value of SUVmean to determine which of multiple lesions should be biopsied, a ROC curve was constructed. ROC curve analysis indicated SUVmean=4.07 or SUVmean/liver=1.66 as a cut-off value.
Our present study suggested that quantitative analysis of 18F-FDG-PET/CT imaging might be useful for selecting the biopsy site in IgG4-RD. The calculation of SUVmean, not of SUVmax, is important for evaluating IgG4-RD-related lesions in 18F-FDG PET/CT imaging.
通过分析 18F-FDG PET/CT 定量方法与组织学发现之间的相关性，探讨 18F-FDG PET/CT 在 IgG4 相关疾病（IgG4-RD）诊断中的应用。
本研究共纳入 21 例 IgG4-RD 患者，这些患者在诊断时均进行了 18F-FDG PET/CT 检查。21 例患者中有 24 个部位进行了组织活检。为了对 18F-FDG PET/CT 成像进行定量分析，测量了像素的最大标准摄取值（SUVmax）和活检病变内的平均 SUV（SUVmean）的最高值。还测量了肝脏的 SUVmean 作为参考。
诊断时的平均年龄为 64.6±11.9 岁，中位血清 IgG4 水平为 650mg/dl。24 个部位中有 19 个部位的组织学发现与 IgG4-RD 相符（组织学阳性）。虽然 SUVmax 在组织学阳性和阴性组织之间没有显著差异，但 SUVmean 在组织学阳性组织中明显更高（分别为 4.98 和 3.54，p<0.05）。SUVmean/liver 也在组织学阳性组织中更高（分别为 2.17 和 1.52，p<0.05）。为了建立 SUVmean 的截断值以确定应进行活检的多个病变中的哪一个，构建了 ROC 曲线。ROC 曲线分析表明 SUVmean=4.07 或 SUVmean/liver=1.66 为截断值。
本研究表明，18F-FDG-PET/CT 成像的定量分析可能有助于选择 IgG4-RD 的活检部位。在 18F-FDG PET/CT 成像中，评估 IgG4-RD 相关病变时，SUVmean 的计算比 SUVmax 更重要。
