title: The utility of FDG-PET/CT and other imaging techniques in the evaluation of IgG4-related disease.
abstract: OBJECTIVE
  This study aimed to evaluate the utility of imaging techniques, including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), in immunoglobulin (IgG)4-related disease (IgG4-RD).
  
  
  METHODS
  We reviewed eight IgG4-RD patients who were referred to our hospital between August 2006 and April 2012. All cases underwent FDG-PET/CT and brain magnetic resonance imaging (MRI) and endobronchial ultrasonography (EBUS) were also performed in five cases and one case, respectively.
  
  
  RESULTS
  Although nearly all patients with IgG4-RD in this study were negative for CRP (mean 0.22 mg/dL), various organ involvement sites were detected by FDG-PET/CT. In the active phase in two autoimmune pancreatitis (AIP) cases, FDG-PET/CT showed longitudinal and heterogeneous FDG accumulation in the pancreas with FDG uptake in the hilar or mediastinal lymph nodes. Follow-up FDG-PET/CT after therapy in one case revealed that the abnormal FDG uptake in all affected lesions had completely disappeared. In two cases, brain MRI revealed asymptomatic hypertrophic pachymeningitis. In one case, EBUS imaging of mediastinal lymph node swelling was consistent with tortuous vessels with high Doppler signals and hyperechoic strands between lymph nodes.
  
  
  CONCLUSIONS
  When FDG-PET/CT shows FDG accumulation, characteristic of IgG4-RD in organs, without evidence of an associated inflammatory reaction, a diagnosis of IgG4-RD can be made. Treatment effects can be assessed by the disappearance of FDG uptake. A routine brain MRI is useful for detecting asymptomatic hypertrophic pachymeningitis. EBUS may also be useful for differentiating among the etiologies of lymphadenopathy with characteristic sonographic imaging findings.
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan. Electronic address: hiroyuki_yjp2005@yahoo.co.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamashita
authors.affiliation: Department of Radiology, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Morooka
authors.affiliation: Department of Radiology, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kubota
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kaneko
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kano
authors.affiliation: Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655 Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Mimori
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology; D001980:Bronchi / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008581:Meningitis / Q000175:diagnosis; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D007074:Immunoglobulin G; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT); Brain magnetic resonance imaging (MRI); Endobronchial ultrasonography (EBUS); Hypertrophic pachymeningitis; Immunoglobulin (IgG)4-related disease (IgG4-RD)