Obstructions in the lower airways lead to altered airflow patterns in the central airway.

A characteristic feature of obstructive lung diseases is the narrowing of small airways, which affects regional airflow patterns within the lung. However, the extent to which these patterns differ between healthy and diseased states is unknown. To investigate airflow patterns in detail, we first used particle image velocimetry measurements to validate a large eddy simulation model of flow in a patient-specific geometry.

In vivo micro particle image velocimetry measurements of blood-plasma in the embryonic avian heart.

The measurement of blood-plasma velocity distributions with spatial and temporal resolution in vivo is inevitable for the determination of shear stress distributions in complex geometries at unsteady flow conditions like in the beating heart. A non-intrusive, whole-field velocity measurement technique is required that is capable of measuring instantaneous flow fields at sub-millimeter scales in highly unsteady flows. Micro particle image velocimetry (muPIV) meets these demands, but requires special consideration and methodologies in order to be utilized for in vivo studies in medical and biological research.