title: Reduced lung uptake of iodine-123 metaiodobenzylguanidine in patients with myeloperoxidase antineutrophil cytoplasmic antibodies-positive vasculitis.
abstract: BACKGROUND
  Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) lung uptake in the early phase has been proposed as a potential marker of endothelial function because MIBG behaves qualitatively similarly to norepinephrine in pulmonary circulation.
  
  
  OBJECTIVE
  The purpose of the present study was to examine the lung uptake of (123)I-MIBG in patients diagnosed with myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA)-associated vasculitis without clinical or radiological abnormalities of the thorax.
  
  
  METHODS
  Six patients with MPO-ANCA-associated vasculitis were enrolled. They had severe renal damage (mean creatinine: 5.1 mg/dl, mean blood urea nitrogen: 54.6 mg/dl), but no respiratory symptoms clinically or radiographic findings on chest computed tomography. The total lung to upper mediastinum ratio of (123)I-MIBG uptake (L/M) 15 min after the injection was measured. The result was compared with those for 6 patients with renal damage due to other diseases (mean creatinine: 6.2 mg/dl, blood urea nitrogen: 51.7 mg/dl) and for 8 healthy subjects.
  
  
  RESULTS
  The mean value of L/M in patients with MPO-ANCA-positive vasculitis was 1.21 +/- 0.04, which was significantly less than that of other groups (1.41 +/- 0.06 for patients with renal failure and 1.45 +/- 0.03 for normal volunteers). There were no significant differences in MIBG accumulation in the heart among the groups.
  
  
  CONCLUSIONS
  The reduction in kinetic behavior of MIBG in the lung reflects the presence of pulmonary endothelial impairment in patients with MPO-ANCA-associated vasculitis, even though there are no clinical manifestations in the lungs.
authors.affiliation: First Department of Internal Medicine, Shinshu University School of Medicine, Asahi, Matsumoto, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Yoshiike
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Koizumi
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Urushihata
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hanaoka
authors.forename: Keishi
authors.initials: K
authors.lastname: Kubo
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D015415:Biomarkers / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000276:immunology / Q000378:metabolism; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D014657:Vasculitis / Q000276:immunology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D015415:Biomarkers; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine