Quantification of 129Xe MRI Ventilation-defect-percent Using Binary-threshold, Gaussian Linear-Binning and K-means Methods: Differences in Asthma and COPD

RATIONALE AND OBJECTIVES: Hyperpolarized ¹²⁹Xe magnetic resonance imaging (MRI) provides a way to quantify ventilation heterogeneity as ventilation defect percent (VDP), calculated as the volume of unventilated lung volume normalized to the thoracic cavity volume. Currently used methods for quantifying VDP include (1) binary signal-intensity thresholds (Binary-threshold, BT), (2) Gaussian transformation of signal-intensity histogram with …