Papers by Alejandra Sofía Ibarra Torres
2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2008
RATHI was introduced as an attempt to further improve the association between anatomical zones an... more RATHI was introduced as an attempt to further improve the association between anatomical zones and specific breathing activity, both spatially and temporally. This work compares RATHI with clinical pulmonary auscultation (PA) to assess the concordance between both procedures to detect asymmetries in lung sound (LS) intensities. Twelve healthy young males participated in the study and were auscultated by two experts. RATHI consisted in the acquisition of acoustical signals with an array of 5x5 sensors, while experts auscultated and described the intensity of LS heard using the same stethoscope on each sensor's position within the array. Comparisons were established looking for intensity asymmetries between apical vs. basal pulmonary regions and right vs. left hemithorax. By RATHI, most of the subjects showed asymmetries between apical and basal regions higher than 20%, whereas between left and right hemithorax asymmetries higher than 20% occurred only half of the time. RATHI and PA agreed 83 to 100% when apical to base acoustical information was compared, but when left to right asymmetries were considered these figures were about 40 to 50%. We concluded that RATHI has advantages as it gave more detailed and measurable information on LS than clinicians, who could not detect intensity asymmetries mainly below 20%.
Medical & Biological Engineering & Computing, 2004
As respiratory sounds contain mechanical and clinical pulmonary information, technical efforts ha... more As respiratory sounds contain mechanical and clinical pulmonary information, technical efforts have been devoted during the past decades to analysing, processing and visualising them. The aim of this work was to evaluate deterministic interpolating functions to generate surface respiratory acoustic thoracic images (RATHIs), based on multiple acoustic sensors. Lung sounds were acquired from healthy subjects through a 5x5 microphone array on the anterior and posterior thoracic surfaces. The performance of five interpolating functions, including the linear, cubic spline, Hermite, Lagrange and nearest neighbour method, were evaluated to produce images of lung sound intensity during both breathing phases, at low (~O.51s 7) and high (~l.01s 7) airflows. Performance indexes included the normalised residual variance nrv (Le. inaccuracy), the prediction covariance cv (Le. precision), the residual covariance rcv (Le. bias) and the maximum squared residual error Semax (i.e. tolerance). Among the tested interpolating functions and in all experimental conditions, the Hermite function (nrv-O.146+O.059, cv-0.925+ 0.030, rcv-O.073+ O.068, Semax-O.O05+ O.O04) globally provided the indexes closest to the optimum, whereas the nearest neighbour (nrv-0.3394-0.023, cv-0.8704-0.033, rcv-0.2984-0.032, Semax-0.0074-0.005) and the Lagrange methods (nrv-0.2874-O. 148, cv-0.8804-0.039, rcv-0.5244-O. 135, Semax-0.0074-0.0001) presented the poorest statistical measurements. It is concluded that, although deterministic interpolation functions indicate different performances among tested techniques, the Hermite interpolation function presents a more confident deterministic interpolation for depicting surface-type RA THI.
Uploads
Papers by Alejandra Sofía Ibarra Torres