title: Clearance of technetium-99m-labeled DTPA in hyperthyroidism without clinical evidence of lung disease, and relation to pulmonary function.
abstract: OBJECTIVE
  The mechanisms of dyspnea and exercise intolerance have not been fully elucidated. We aimed to investigate the clearance rate of technetium-99m diethyltriaminepentaaceticacid (Tc-99m DTPA) from lungs in hyperthyroid patients without clinical evidence of lung disease and to explore the interactions between their Tc-99m DTPA radioaerosol lung scintigraphy, spirometric measurements, and the levels of thyroid hormones.
  
  
  METHODS
  We studied 19 hyperthyroid patients and 16 sex- and age-matched controls. Thyroid hormone levels were assessed. Spirometric lung function tests, diffusing capacity of the lung for carbon monoxide (DLCO) and the clearance rate of Tc-99m DTPA were performed in all participants. Ratio of DLCO value to the alveolar ventilation (DLCO/VA) and the means of half-time (T1/2) of Tc-99m DTPA clearance rate, which were used to evaluate alveolar-capillary membrane permeability, were calculated.
  
  
  RESULTS
  There were no statistical differences between spirometric parameters (VC, FVC, FEV1/FVC, FEF 25-75) of the two groups (p > 0.05). Although the mean FEV1 level was significantly lower in the hyperthyroid patients than the control subjects (p < 0.01), in five patients FEV1 was only less than 80 percent of the predicted value. No significant difference in the means of DLCO, DLCO/VA or T1/2 values of Tc-99m DTPA clearance was observed between the two groups (p > 0.05). In hyperthyroid patients, there was a positive relation between DLCO/VA, DLCO/VA % and T1/2 values of Tc-99m DTPA clearance (p < 0.01, r = 0.732, p < 0.01, r = 0.742, respectively). The lung volumes and the levels of thyroid hormones did not show a significant relationship to T1/2 values of Tc-99m DTPA clearance in hyperthyroid group (p > 0.05).
  
  
  CONCLUSIONS
  We conclude that increased thyroid hormones have no effect on permeability of alveolar-capillary membrane in hyperthyroid patients.
authors.affiliation: Department of Endocrinology and Metabolism, Trakya University School of Medicine, Turkey. sguldiken@trakya.edu.tr
authors.forename: Sibel
authors.initials: S
authors.lastname: Guldiken
authors.forename: Armagan
authors.initials: A
authors.lastname: Tugrul
authors.forename: Gundeniz
authors.initials: G
authors.lastname: Altiay
authors.forename: Sevim
authors.initials: S
authors.lastname: Hacimahmutoglu
authors.forename: Gülay
authors.initials: G
authors.lastname: Durmuş-Altun
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008171:Lung Diseases / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012129:Respiratory Function Tests; D013147:Spirometry; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D000336:Aerosols; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate