Spatial Heterogeneity of Lung Strain and Aeration and Regional Inflammation During Early Lung Injury Assessed with PET/CT

Despite the introduction of new radiotherapy techniques, such as intensity modulated radiation therapy or stereotactic body radiation therapy, radiation induced lung injury remains a significant treatment related adverse event of thoracic radiation therapy. Functional lung avoidance radiation therapy is an emerging concept in the treatment of lung disease to better preserve lung function and to reduce pulmonary toxicity. While conventional ventilation/perfusion (V/Q) lung scintigraphy is limited by a relatively low spatial and temporal resolution, the recent advent of 68Gallium V/Q lung PET/CT imaging offers a potential to increase the accuracy of lung functional mapping and to better tailor lung radiation therapy plans to the individual's lung function. Lung PET/CT imaging may also improve our understanding of radiation induced lung injury compared to the current anatomical based dose–volume constraints. In this review, recent advances in radiation therapy for the management of primary and secondary lung tumors and in V/Q PET/CT imaging for the assessment of functional lung volumes are reviewed. The new opportunities and challenges arising from the integration of V/Q PET/CT imaging in radiation therapy planning are also discussed.

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Positive end-expiratory pressure alters the severity and spatial heterogeneity of ventilator-induced lung injury: An argument for cyclical airway collapse

Journal of Critical Care ◽

10.1016/j.jcrc.2008.04.005 ◽

2009 ◽

Vol 24 (2) ◽

pp. 206-211 ◽

Cited By ~ 23

Author(s):

Scott E. Sinclair ◽

Emil Chi ◽

Hen-I Lin ◽

William A. Altemeier

Keyword(s):

Lung Injury ◽

Spatial Heterogeneity ◽

Positive End Expiratory Pressure ◽

Ventilator Induced Lung Injury ◽

Airway Collapse

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Mechanical Power Correlates With Lung Inflammation Assessed by Positron-Emission Tomography in Experimental Acute Lung Injury in Pigs

Frontiers in Physiology ◽

10.3389/fphys.2021.717266 ◽

2021 ◽

Vol 12 ◽

Author(s):

Martin Scharffenberg ◽

Jakob Wittenstein ◽

Xi Ran ◽

Yingying Zhang ◽

Anja Braune ◽

...

Keyword(s):

Positron Emission Tomography ◽

Acute Lung Injury ◽

Lung Injury ◽

Uptake Rate ◽

Emission Tomography ◽

Mechanical Power ◽

Relative Mass ◽

Neutrophilic Inflammation ◽

Positron Emission ◽

Pet Ct

Background: Mechanical ventilation (MV) may initiate or worsen lung injury, so-called ventilator-induced lung injury (VILI). Although different mechanisms of VILI have been identified, research mainly focused on single ventilator parameters. The mechanical power (MP) summarizes the potentially damaging effects of different parameters in one single variable and has been shown to be associated with lung damage. However, to date, the association of MP with pulmonary neutrophilic inflammation, as assessed by positron-emission tomography (PET), has not been prospectively investigated in a model of clinically relevant ventilation settings yet. We hypothesized that the degree of neutrophilic inflammation correlates with MP.Methods: Eight female juvenile pigs were anesthetized and mechanically ventilated. Lung injury was induced by repetitive lung lavages followed by initial PET and computed tomography (CT) scans. Animals were then ventilated according to the acute respiratory distress syndrome (ARDS) network recommendations, using the lowest combinations of positive end-expiratory pressure and inspiratory oxygen fraction that allowed adequate oxygenation. Ventilator settings were checked and adjusted hourly. Physiological measurements were conducted every 6 h. Lung imaging was repeated 24 h after first PET/CT before animals were killed. Pulmonary neutrophilic inflammation was assessed by normalized uptake rate of 2-deoxy-2-[18F]fluoro-D-glucose (KiS), and its difference between the two PET/CT was calculated (ΔKiS). Lung aeration was assessed by lung CT scan. MP was calculated from the recorded pressure–volume curve. Statistics included the Wilcoxon tests and non-parametric Spearman correlation.Results: Normalized 18F-FDG uptake rate increased significantly from first to second PET/CT (p = 0.012). ΔKiS significantly correlated with median MP (ρ = 0.738, p = 0.037) and its elastic and resistive components, but neither with median peak, plateau, end-expiratory, driving, and transpulmonary driving pressures, nor respiratory rate (RR), elastance, or resistance. Lung mass and volume significantly decreased, whereas relative mass of hyper-aerated lung compartment increased after 24 h (p = 0.012, p = 0.036, and p = 0.025, respectively). Resistance and PaCO2 were significantly higher (p = 0.012 and p = 0.017, respectively), whereas RR, end-expiratory pressure, and MP were lower at 18 h compared to start of intervention.Conclusions: In this model of experimental acute lung injury in pigs, pulmonary neutrophilic inflammation evaluated by PET/CT increased after 24 h of MV, and correlated with MP.

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Longitudinal Imaging Using PET/CT with Collagen-I PET-Tracer and MRI for Assessment of Fibrotic and Inflammatory Lesions in a Rat Lung Injury Model

Journal of Clinical Medicine ◽

10.3390/jcm9113706 ◽

2020 ◽

Vol 9 (11) ◽

pp. 3706 ◽

Cited By ~ 1

Author(s):

Irma Mahmutovic Persson ◽

Nina Fransén Pettersson ◽

Jian Liu ◽

Hanna Falk Håkansson ◽

Anders Örbom ◽

...

Keyword(s):

Lung Injury ◽

Imaging Techniques ◽

Collagen I ◽

Imaging Biomarkers ◽

Drug Induced ◽

Non Invasive ◽

Pet Tracer ◽

Pet Ct ◽

Activity Measurements ◽

Longitudinal Imaging

Non-invasive imaging biomarkers (IBs) are warranted to enable improved diagnostics and follow-up monitoring of interstitial lung disease (ILD) including drug-induced ILD (DIILD). Of special interest are IB, which can characterize and differentiate acute inflammation from fibrosis. The aim of the present study was to evaluate a PET-tracer specific for Collagen-I, combined with multi-echo MRI, in a rat model of DIILD. Rats were challenged intratracheally with bleomycin, and subsequently followed by MRI and PET/CT for four weeks. PET imaging demonstrated a significantly increased uptake of the collagen tracer in the lungs of challenged rats compared to controls. This was confirmed by MRI characterization of the lesions as edema or fibrotic tissue. The uptake of tracer did not show complete spatial overlap with the lesions identified by MRI. Instead, the tracer signal appeared at the borderline between lesion and healthy tissue. Histological tissue staining, fibrosis scoring, lysyl oxidase activity measurements, and gene expression markers all confirmed establishing fibrosis over time. In conclusion, the novel PET tracer for Collagen-I combined with multi-echo MRI, were successfully able to monitor fibrotic changes in bleomycin-induced lung injury. The translational approach of using non-invasive imaging techniques show potential also from a clinical perspective.

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Prone position delays the progression of ventilator-induced lung injury in rats: Does lung strain distribution play a role?*

Critical Care Medicine ◽

10.1097/01.ccm.0000150660.45376.7c ◽

2005 ◽

Vol 33 (2) ◽

pp. 361-367 ◽

Cited By ~ 90

Author(s):

Franco Valenza ◽

Massimiliano Guglielmi ◽

Micol Maffioletti ◽

Cecilia Tedesco ◽

Patrizia Maccagni ◽

...

Keyword(s):

Lung Injury ◽

Prone Position ◽

Strain Distribution ◽

Ventilator Induced Lung Injury ◽

Lung Strain

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Early detection value of 18F-FDG-PET/CT for drug-induced lung injury in lymphoma

Annals of Hematology ◽

10.1007/s00277-018-3558-4 ◽

2018 ◽

Vol 98 (4) ◽

pp. 909-914 ◽

Cited By ~ 1

Author(s):

Meixin Zhao ◽

Weifang Zhang

Keyword(s):

Early Detection ◽

Lung Injury ◽

Fdg Pet ◽

Drug Induced ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

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Regional tidal lung strain in mechanically ventilated normal lungs

Journal of Applied Physiology ◽

10.1152/japplphysiol.00861.2015 ◽

2016 ◽

Vol 121 (6) ◽

pp. 1335-1347 ◽

Cited By ~ 17

Author(s):

Luis Felipe Paula ◽

Tyler J. Wellman ◽

Tilo Winkler ◽

Peter M. Spieth ◽

Andreas Güldner ◽

...

Keyword(s):

Lung Injury ◽

Tidal Volume ◽

Lung Volume ◽

Mechanically Ventilated ◽

Reference Volume ◽

Ventilator Induced Lung Injury ◽

Vertical Heterogeneity ◽

Dorsal Axis ◽

Lung Strain ◽

Normal Lungs

Parenchymal strain is a key determinant of lung injury produced by mechanical ventilation. However, imaging estimates of volumetric tidal strain (ε = regional tidal volume/reference volume) present substantial conceptual differences in reference volume computation and consideration of tidally recruited lung. We compared current and new methods to estimate tidal volumetric strains with computed tomography, and quantified the effect of tidal volume (VT) and positive end-expiratory pressure (PEEP) on strain estimates. Eight supine pigs were ventilated with VT = 6 and 12 ml/kg and PEEP = 0, 6, and 12 cmH2O. End-expiratory and end-inspiratory scans were analyzed in eight regions of interest along the ventral-dorsal axis. Regional reference volumes were computed at end-expiration (with/without correction of regional VT for intratidal recruitment) and at resting lung volume (PEEP = 0) corrected for intratidal and PEEP-derived recruitment. All strain estimates demonstrated vertical heterogeneity with the largest tidal strains in middependent regions ( P < 0.01). Maximal strains for distinct estimates occurred at different lung regions and were differently affected by VT-PEEP conditions. Values consistent with lung injury and inflammation were reached regionally, even when global measurements were below critical levels. Strains increased with VT and were larger in middependent than in nondependent lung regions. PEEP reduced tidal-strain estimates referenced to end-expiratory lung volumes, although it did not affect strains referenced to resting lung volume. These estimates of tidal strains in normal lungs point to middependent lung regions as those at risk for ventilator-induced lung injury. The different conditions and topography at which maximal strain estimates occur allow for testing the importance of each estimate for lung injury.

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Progression of regional lung strain and heterogeneity in lung injury: assessing the evolution under spontaneous breathing and mechanical ventilation

Annals of Intensive Care ◽

10.1186/s13613-020-00725-0 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Daniel E. Hurtado ◽

Benjamín Erranz ◽

Felipe Lillo ◽

Mauricio Sarabia-Vallejos ◽

Pablo Iturrieta ◽

...

Keyword(s):

Mechanical Ventilation ◽

Lung Injury ◽

Spontaneous Breathing ◽

Regional Lung ◽

Lung Strain

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Nódulo pulmonar solitario

Studies in the Economic History of Southern Africa ◽

10.22201/fm.24484865e.2020.63.2.05 ◽

2020 ◽

Vol 63 (2) ◽

pp. 33-35

Author(s):

César Nicolás Cristancho Rojas ◽

Edith García Luna ◽

Belén Rivera Bravo ◽

Keren Contreras Contreras

Keyword(s):

Lung Cancer ◽

Lung Injury ◽

Key Words ◽

Pulmonary Nodule ◽

Clinical Picture ◽

Solitary Pulmonary Nodule ◽

Left Lung ◽

Image Study ◽

Pet Ct ◽

History Of

63 year old female patient with a clinical picture of 3 months of evolution manifested by dry cough, with no history of smoking. An image study identified left lung injury which was performed biopsy. Key words: Solitary pulmonary nodule; lung cancer; PET / CT; 18FFDG; FDG.

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