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

Abstract

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 (A 1) 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, A 1, and MUD-MDD) among four groups (one way ANOVA, p = 0.0001 for MUD-MDD, SDx, and SDv, p = 0.0002 for A 1). In ROC analysis, the cutoff values were 0.11 for SDx (AUC: 0.982, p < 0.0001), 0.062 for SDv (AUC: 0.847, p < 0.0001), 0.117 for A 1 (AUC: 0.876, p < 0.0001), and 0.349 for MUD-MDD (AUC: 0.948, p < 0.0001). 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.

Exploring neural and peripheral physiological correlates of simulator sickness

“…We found no regularity changes across the ( G exp ) and ( G ctrl ). Respiration amplitude was visually analyzed using phase space diagrams that show velocity as a function of sensor displacement and is useful for visualizing oscillatory processes like respiration 35 . Visually, as well as quantitatively, respiration amplitude is not affected by the experimental manipulation ( p = .69, t = 0.41).…”

“…Visually, as well as quantitatively, respiration amplitude is not affected by the experimental manipulation ( p = .69, t = 0.41). Finally, using Rosenstein's LLE method, we analyse respiration wave forms by considering the respiratory system as a dynamical and chaotic system 35 . A positive LLE is a sign of chaos and shows instability in a particular direction whereas a negative LLE represents the tendency to converge towards a stable state.…”

Effectiveness of Respiratory-gated Positron Emission Tomography/Computed Tomography for Radiotherapy Planning in Patients with Lung Carcinoma – A Systematic Review

“…Too small a percentage of the data will lead to insufficient counts, whereas too great a percentage of the data included predisposes the study to more movement artefact which would nullify the purpose of respiratory gating. This becomes increasingly more difficult when trying to accommodate for irregular breathing patterns [8]. Also, the misalignment of the gated PET and CT data has the potential for inaccuracies in SUV measurement [4] [9].…”

Respiratory-gated PET/CT for pulmonary lesion characterisation—promises and problems

“…Amplitude-gating has been demonstrated to be superior to phase-based gating in these patients. 18 In addition, coaching patients before/whilst they are on the scanner can improve the regularity of their breathing cycle. 19 Breath-hold techniques can be employed as a way of reconstructing data from the expiratory phase of the respiratory cycle however this is limited by patient co-operation.…”