title: A fractal approach for evaluation of pulmonary circulation in man at rest and during exercise.
abstract: Changes in pulmonary circulation caused by muscular exercise and body position are usual in daily life. By using first-pass radiocardiography and fractal analysis, pulmonary circulation in man was evaluated at rest and during muscular exercise. At rest, pulmonary circulation was heterogeneous as described by the relative dispersion (which is the coefficient of variation, i.e. the standard deviation of the pulmonary transit times divided by the mean transit time; RD = 0.51 +/- 0.06) and fractal in nature. During exercise, pulmonary circulation became more homogeneous (RD = 0.35 +/- 0.04; P < 0.001). The calculated fractal dimension decreases from 1.09 at rest to 1.06 during exercise. The model identifies a cubic-law response for circulation heterogeneity and a quarter-power law for resistance during muscular exercise.
authors: Department of Clinical Physiology, Kuopio University Hospital, Finland.
authors: J T
authors: JT
authors: Kuikka
authors: E
authors: E
authors: Länsimies
mesh_terms: D000328:Adult; D000465:Algorithms; D001810:Blood Volume / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003627:Data Interpretation, Statistical; D015444:Exercise / Q000502:physiology*; D017709:Fractals; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D015609:Organotechnetium Compounds; D011652:Pulmonary Circulation / Q000502:physiology*; D011877:Radionuclide Imaging; D012146:Rest / Q000502:physiology*; D012709:Serum Albumin; D016278:Ventricular Function, Right / Q000502:physiology
chemical_list: D015609:Organotechnetium Compounds; D012709:Serum Albumin; C107869:technetium Tc 99m serum albumin