Recently, an alternative proton lung MRI Fourier Decomposition (FD) method for phase resolved functional lung imaging (PREFUL) was proposed. Using a sine model, respiratory and cardiac cycles with increased temporal resolution are obtained, enabling the assessment of dynamic parameters. Similar to flow-volume loops in spirometry, the regional ventilation can be quantified in terms of fractional ventilation (FV) loops. In this study the FV loops of six healthy volunteers and 16 chronic obstructive pulmonary disease patients are evaluated. As a metric the cross-correlation to a healthy reference is used. The results suggest potential benefits for early detection or treatment monitoring.