title: Use of electrical impedance tomography (EIT) for the assessment of unilateral pulmonary function.
abstract: We describe a fully automatable quantification process for the assessment of unilateral pulmonary function (UPF) by means of EIT and propose a measurement protocol for its clinical implementation. Measurements were performed at the fourth and sixth intercostal levels on a first group of ten healthy subjects (5M, 5F, ages 26-48 years) to define the proper protocol by evaluating the most common postures and ventilation modes. Several off-line processing tools were also evaluated, including the use of digital filters to extract the respiratory components from EIT time series. Comparative measures were then carried out on a second group consisting of five preoperatory patients with lung cancer (4M, IF, ages 25-77 years) scheduled for radionuclide scanning. Results show that measurements were best performed with the subject sitting down, holding his arms up and breathing spontaneously. As regards data processing, it is best to extract Fourier respiratory components. The mean of the healthy subject group leads to a left-right division of lung ventilation consistent with literature values (47% left lung, 53% right lung). The comparative study indicates a good correlation (r = 0.96) between the two techniques, with a mean difference of (-0.4+/-5.4)%, suggesting that the elimination of cardiac components from the thoracic transimpedance signal leads to a better estimation of UPF.
authors.affiliation: Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, Barcelona, Spain. eserrano@eel.upc.es
authors.forename: Roberto E
authors.initials: RE
authors.lastname: Serrano
authors.forename: Lema Bruno
authors.initials: LB
authors.lastname: de
authors.forename: Oscar
authors.initials: O
authors.lastname: Casas
authors.forename: Teresa
authors.initials: T
authors.lastname: Feixas
authors.forename: Nuria
authors.initials: N
authors.lastname: Calaf
authors.forename: Valle
authors.initials: V
authors.lastname: Camacho
authors.forename: Ignasi
authors.initials: I
authors.lastname: Carrió
authors.forename: Pere
authors.initials: P
authors.lastname: Casan
authors.forename: J
authors.initials: J
authors.lastname: Sanchis
authors.forename: Pere J
authors.initials: PJ
authors.lastname: Riu
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology*; D008175:Lung Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012129:Respiratory Function Tests / Q000379:methods*; D013670:Sodium Pertechnetate Tc 99m; D012984:Software; D014054:Tomography / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m