The laboratory has developed an in-situ MRI technique to measure airway morphometry along with an MRI-based method to quantify the spatial distribution of deposited particles in rodent lungs. The technique uses the change in signal decay rate (R2*), due to the presence of iron oxide particles, to quantify deposition. We showed that R2* was higher in rat lungs exposed to iron-oxide particles, compared with control lungs and that this difference in R2* reflected the presence of deposited particles in lung tissue. We then applied this technique to the study of the effect of gravity on the deposition of fine particles and to the study of aerosol deposition in emphysematous lungs. We have shown that, for similar breathing patterns and aerosol exposure, particle deposition was higher and more heterogeneously distributed in emphysematous lungs when compared to healthy lungs. These MRI studies have generated rich experimental datasets that can also be used to validate in-silico models of aerosol transport in the lung.
Experimental approaches include:
- Aerosol exposure during mechanical ventilation
- Animal plethysmography
- Oakes, J.M., M. Scadeng, E.C. Breen, A.L. Marsden and C. Darquenne. Rat airway morphometry measured from in-situ MRI-based geometric models. J. Appl. Physiol., 112:1921-1931, 2012 (doi:10.1152/japplphysiol.00018.2012, PMC3379152).
- Oakes, J.M., M. Scadeng, E.C. Breen, G.K. Prisk and C. Darquenne. Regional distribution of aerosol deposition in rat lungs using magnetic resonance imaging. Ann. Biomed. Eng., 41:967-978, 2013. (DOI: 10.1007/s10439-013-0745-2, NIHMS439396, PMC3625510)
- Oakes, J.M., E. Breen, M. Scadeng, G.S. Tchantchou and C. Darquenne. MRI-based measurements of aerosol deposition in the lung of healthy and elastase-treated rats. J. Appl. Physiol., 116:1561-1568, 2014 (DOI: 10.1152/japplphysiol.01165.2013, PMC4064380).
- Oakes, J.M., A.L. Marsden, C. Grandmont, C. Darquenne, and I.E. Vignon-Clementel. Distribution of aerosolized particles in healthy and emphysematous rat lungs: comparison between experimental and numerical studies. J. Biomech., 48: 1147–1157, 2015 (DOI: 10.1016/j.jbiomech.2015.01.004).
A full list of publications can be found on Chantal Darquenne's UCSD profile page.