title: Ventilation perfusion scintigraphy and lung function testing to assess metal stent efficacy.
abstract: Stent implantation in malignant bronchial stenoses is a highly effective method of providing symptomatic relief by restoring bronchial patency. Whether an improvement in ventilatory conditions is paralleled by an increase in blood flow and gas exchange has not yet been determined.
  
  
  METHODS
  Fourteen patients with malignant, high-grade obstruction of bronchi who had metal stent implantation were investigated. Before the intervention and again 8 days afterward, both quantitative technegas ventilation and 99mTc-MAA perfusion scans (V/Q scans) and lung function tests were performed.
  
  
  RESULTS
  Stent implantation was successful in all patients, with a significant reduction in the degree of bronchial stenosis (pre-stent: 93% +/- 1.5%; post-stent: 16% +/- 3.5%). After stent implantation, ventilation scintigraphy revealed an improvement in tracer deposition by 65% (pre-stent: 37% +/- 8%; post-stent: 61% +/- 6%; p < 0.05) within the affected lung. A complementary increase of 71% by perfusion scintigraphy was obtained (pre-stent: 27% +/- 4%; post-stent: 46% +/- 5%; p < 0.01%). Based on scintigraphic criteria, stenting was successful in 93% (n = 13) of all patients. Lung function studies performed after the intervention showed significant improvement in vital capacity (VC, p < 0.01), forced expiratory volume in 1 sec (FEV1, p < 0.05), peak expiratory flow (PEF, p < 0.05), arterial oxygen (PaO2, p < 0.05) and carbon dioxide (PaCO2, p < 0.05) tension, and oxygen saturation (p < 0.05).
  
  
  CONCLUSIONS
  Stenting of malignant high-grade bronchial obstructions leads to an increase in bronchial patency and in activity distribution of both ventilation and perfusion scintigraphy of the affected lung, accompanied by significant improvement in lung function parameters.
authors.affiliation: Department 1 of Internal Medicine, Klinikum rechts der Isar, Munich, Germany.
authors.forename: R W
authors.initials: RW
authors.lastname: Hauck
authors.forename: W
authors.initials: W
authors.lastname: Römer
authors.forename: C
authors.initials: C
authors.lastname: Schulz
authors.forename: R M
authors.initials: RM
authors.lastname: Lembeck
authors.forename: A
authors.initials: A
authors.lastname: Schömig
authors.forename: M
authors.initials: M
authors.lastname: Schwaiger
mesh_terms: D000497:Alloys; D001982:Bronchial Diseases / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy*; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy; D004867:Equipment Design; D005260:Female; D006108:Graphite; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000150:complications; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012129:Respiratory Function Tests; D013670:Sodium Pertechnetate Tc 99m; D015607:Stents; D013635:Tantalum; D013668:Technetium Tc 99m Aggregated Albumin; D014692:Ventilation-Perfusion Ratio
chemical_list: D000497:Alloys; D013668:Technetium Tc 99m Aggregated Albumin; C056708:Technegas; C013616:nitinol; D013635:Tantalum; D006108:Graphite; D013670:Sodium Pertechnetate Tc 99m