Characterizing IgG4-related disease with ¹⁸F-FDG PET/CT: a prospective cohort study.
OBJECTIVE
IgG4-related disease (IgG4-RD) is an increasingly recognized clinicopathological disorder with immune-mediated inflammatory lesions mimicking malignancies. A cohort study was prospectively designed to investigate the value of (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in characterizing IgG4-RD.


METHODS
Thirty-five patients diagnosed with IgG4-RD according to the consensus criteria were enrolled with informed consent. All patients underwent baseline (18)F-FDG PET/CT evaluation. Among them, 29 patients underwent a second (18)F-FDG PET/CT scan after 2 to 4 weeks of steroid-based therapy.


RESULTS
All 35 patients were found with (18)F-FDG-avid hypermetabolic lesion(s); 97.1% (34/35) of these patients showed multi-organ involvement. Among the 35 patients, 71.4% (25/35) patients were found with more organ involvement on (18)F-FDG PET/CT than conventional evaluations including physical examination, ultrasonography, and computed tomography (CT). (18)F-FDG PET/CT demonstrated specific image characteristics and pattern of IgG4-RD, including diffusely elevated (18)F-FDG uptake in the pancreas and salivary glands, patchy lesions in the retroperitoneal region and vascular wall, and multi-organ involvement that cannot be interpreted as metastasis. Comprehensive understanding of all involvement aided the biopsy-site selection in seven patients and the recanalization of ureteral obstruction in five patients. After 2 to 4 weeks of steroid-based therapy at 40 mg to 50 mg prednisone per day, 72.4% (21/29) of the patients showed complete remission, whereas the others exhibited > 81.8% decrease in (18)F-FDG uptake.


CONCLUSIONS
F-FDG PET/CT is a useful tool for assessing organ involvement, monitoring therapeutic response, and guiding interventional treatment of IgG4-RD. The image pattern is suggested to be updated into the consensus diagnostic criteria for IgG4-RD.
Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, China.
Jingjing
J
Zhang
Hua
H
Chen
Yanru
Y
Ma
Yu
Y
Xiao
Na
N
Niu
Wei
W
Lin
Xinwei
X
Wang
Zhiyong
Z
Liang
Fengchun
F
Zhang
Fang
F
Li
Wen
W
Zhang
Zhaohui
Z
Zhu
D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
D007074:Immunoglobulin G; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18