title: Impaired lung 123I-MIBG uptake on SPECT in pulmonary emphysema.
abstract: The aim of this study was to evaluate impaired lung uptake of (123)I-metaiodobenzylguanidine ((123)I-MIBG) on SPECT, compared with perfusion SPECT and morphologic CT, in patients with pulmonary emphysema (PE).
  
  
  METHODS
  (123)I-MIBG SPECT was performed at 15 min and 4 h after intravenous injection of (123)I-MIBG in 36 PE patients with a history of smoking and variable-extent low-attenuation areas on CT, indicative of emphysematous changes, and in 16 controls with no history of smoking and no noticeable low-attenuation areas. The distribution of (123)I-MIBG was compared with that of low-attenuation areas on CT and perfusion on SPECT at the base of the 180 lung lobes of the PE patients. Total-lung (123)I-MIBG kinetics were calculated, including early and delayed lung-to-mediastinum uptake ratios and washout rate.
  
  
  RESULTS
  The controls showed a fairly uniform lung (123)I-MIBG distribution nearly consistent with perfusion. PE patients had heterogeneous (123)I-MIBG defects showing frequent discordance with low-attenuation areas or perfusion distribution; (123)I-MIBG defects were more extensive than low-attenuation areas in 76 lobes (42.2%) of 31 patients (86%) and more extensive than perfusion defects in 44 lobes (24.4%) of 22 patients (61%). (123)I-MIBG defects were seen regardless of the absence of noticeable low-attenuation areas and perfusion defects in 19 lobes (10.5%) of 16 patients (44%). All total-lung (123)I-MIBG kinetic parameters in PE patients were significantly lower than the control values (P < 0.0001), with significant correlation with alveolar-arterial oxygen tension gradient but without correlation with the extent of perfusion defects or low-attenuation areas.
  
  
  CONCLUSIONS
  (123)I-MIBG SPECT allows evaluation of lung pathophysiology in PE independently of perfusion SPECT or morphologic CT, and impairment of lung (123)I-MIBG uptake may be more extensive than perfusion or morphologic abnormalities in PE.
authors.affiliation: Department of Radiology, St Hill Hospital, Yamaguchi, Japan. sugar@sthill-hp.or.jp
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Suga
authors.forename: Munemasa
authors.initials: M
authors.lastname: Okada
authors.forename: Mitsue
authors.initials: M
authors.lastname: Kunihiro
authors.forename: Osamu
authors.initials: O
authors.lastname: Tokuda
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Iwanaga
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation / Q000502:physiology; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012907:Smoking / Q000009:adverse effects; D013909:Thorax / Q000000981:diagnostic imaging; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine