- Poster presentation
- Open Access
Lung inhomogeneities, inflation and [18F]FDG uptake rate in ards
Intensive Care Medicine Experimental volume 3, Article number: A90 (2015)
In ARDS lung parenchyma presents great variability in inflation, lung inhomogeneities and [18F]FDG uptake. In fact, inflation progressively decreases along the sternum-vertebral axis leading to further inhomogeneities that may act as “stress raiser”. That can activate a local inflammatory response leading to edema.
We aimed to examine the voxel by voxel relationship between [18F]FDG uptake and inhomogeneity according to the actual classification of ARDS.
20 ARDS patients underwent a PET-CT scan at 10 cmH2O. [18F]FDG uptake was determined with the graphical Patlak approach voxel by voxel. Lung inhomogeneities were determined by measuring the gas/tissue ratio in two contiguous lung regions. We defined inhomogeneities the fraction of lung volume whose inhomogeneities were greater than 1.61.
5 patients presented mild, 12 moderate and 3 severe ARDS. In mild and moderate ARDS a consistent lung fraction is homogeneous with a high [18F]FDG metabolic activity (53 ± 14% and 53 ± 20%). Inhomogeneous lung fraction with a higher [18F]FDG uptake increases from mild to severe (12 ± 3%, 16 ± 9% and 27 ± 11%). On the other hand, the homogeneous parenchyma with normal [18F]FDG uptake decreases in worse ARDS (33 ± 14%, 26 ± 20% and 5 ± 9%).
Our findings indicate that the actual classification of ARDS from mild to severe reflects the underlying pathophysiology. In fact, while a similar sized homogeneous and inflamed/metabolically more active compartment is present in all the ARDS patients, in mild ARDS it is associated with a consistent fraction of normal lung while in severe ARDS is primarily associated with inhomogeneous, inflamed/metabolically more active lung tissue.
Gattinoni L: Intensive Care Med. 2005, 31 (6): 776-84. 10.1007/s00134-005-2627-z.
Mead J: J Appl Physiol. 1970, 28 (5): 596-608.
Patlak CS: J Cereb Blood Flow Metab. 1983, 3 (1): 1-7. 10.1038/jcbfm.1983.1.
Cressoni M: Am J Respir Crit Care Med. 2013
About this article
Cite this article
Cressoni, M., Chiumello, D., Brioni, M. et al. Lung inhomogeneities, inflation and [18F]FDG uptake rate in ards. ICMx 3, A90 (2015). https://doi.org/10.1186/2197-425X-3-S1-A90
- Lung Volume
- Normal Lung
- Lung Parenchyma
- Stress Raiser
- Actual Classification