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BioMed Research International
Volume 2016, Article ID 7862539, 11 pages
Research Article

Visual and Quantitative Analysis Methods of Respiratory Patterns for Respiratory Gated PET/CT

1Department of Nuclear Medicine, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Republic of Korea
2The Dong-A Anti-Aging Research Institute, Dong-A University, Busan, Republic of Korea

Received 19 May 2016; Accepted 28 September 2016

Academic Editor: Hidetaka Arimura

Copyright © 2016 Hye Joo Son et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We integrated visual and quantitative methods for analyzing the stability of respiration using four methods: phase space diagrams, Fourier spectra, Poincaré maps, and Lyapunov exponents. Respiratory patterns of 139 patients were grouped based on the combination of the regularity of amplitude, period, and baseline positions. Visual grading was done by inspecting the shape of diagram and classified into two states: regular and irregular. Quantitation was done by measuring standard deviation of x and v coordinates of Poincaré map (SDx, SDv) or the height of the fundamental peak (A1) in Fourier spectrum or calculating the difference between maximal upward and downward drift. Each group showed characteristic pattern on visual analysis. There was difference of quantitative parameters (SDx, SDv, A1, and MUD-MDD) among four groups (one way ANOVA, for MUD-MDD, SDx, and SDv, for A1). In ROC analysis, the cutoff values were 0.11 for SDx (AUC: 0.982, ), 0.062 for SDv (AUC: 0.847, ), 0.117 for A1 (AUC: 0.876, ), and 0.349 for MUD-MDD (AUC: 0.948, ). This is the first study to analyze multiple aspects of respiration using various mathematical constructs and provides quantitative indices of respiratory stability and determining quantitative cutoff value for differentiating regular and irregular respiration.