A system (100) includes an imaging system (102) and a pressure delivery system (104). The imaging system includes a data acquisition system (114 and 116) and is configured to produce data. The pressure delivery system is configured to produce a periodic airflow variation. The system further includes an operator console (120) configured to control the imaging system to scan a subject receiving the periodic airflow variation and map the periodic airflow variation and first data. The system further includes a reconstructor (516) configured to reconstruct the first data and generate first volumetric image data indicative of the periodic airflow variation.