Regional lung function and heterogeneity of specific gas volume in healthy and emphysematous subjects

The aim of our study was to study regional lung function by standard computed tomography (CT) and characterise regional variations of density and specific gas volume (SVg) between different lung volumes. We studied 10 healthy and 10 severely emphysematous subjects. Corresponding CT images taken at high and low lung volumes were registered by optical flow to obtain two-dimensional maps of pixel-by-pixel differences of density (&Dgr;HU) and SVg (&Dgr;SVg) at slice levels near the aortic arch, carina and top diaphragm. In healthy subjects, &Dgr;HU was higher at all levels (p<0.001) with higher variability expressed as interquartile range (p<0.001), largely due to its differences between dorsal and ventral regions. In patients, median &Dgr;SVg values were 3.2 times lower than healthy volunteers (p<0.001), while heterogeneity of &Dgr;SVg maps, expressed as quartile coefficient of variation, was 5.4 times higher (p<0.001). In all patients, there were areas with negative values of &Dgr;SVg. In conclusion, &Dgr;SVg is uniform in healthy lungs and minimally influenced by gravity. The significant &Dgr;SVg heterogeneity observed in emphysema allows identification of areas of alveolar destruction and gas trapping and suggests that &Dgr;SVg maps provide useful information for evaluation and planning of emerging treatments that target trapped gas for removal.

[1]  A. Aliverti,et al.  Influence of CT reconstruction settings on extremely low attenuation values for specific gas volume calculation in severe emphysema. , 2011, Academic radiology.

[2]  D. Slebos,et al.  Bronchoscopic lung-volume reduction with Exhale airway stents for emphysema (EASE trial): randomised, sham-controlled, multicentre trial , 2011, The Lancet.

[3]  F. Herth,et al.  Bronchoscopic lung volume reduction with a dedicated coil: a clinical pilot study , 2010, Therapeutic advances in respiratory disease.

[4]  G. Snell,et al.  A feasibility and safety study of bronchoscopic thermal vapor ablation: a novel emphysema therapy. , 2009, The Annals of thoracic surgery.

[5]  G. McLennan,et al.  Biologic lung volume reduction therapy for advanced homogeneous emphysema , 2009, European Respiratory Journal.

[6]  Andrea Aliverti,et al.  Quantification of trapped gas with CT and 3 He MR imaging in a porcine model of isolated airway obstruction. , 2009, Radiology.

[7]  N. Aljuri,et al.  Validation and pilot clinical study of a new bronchoscopic method to measure collateral ventilation before endobronchial lung volume reduction. , 2009, Journal of applied physiology.

[8]  P. Macklem,et al.  Airway bypass improves the mechanical properties of explanted emphysematous lungs. , 2008, American journal of respiratory and critical care medicine.

[9]  T. Pilgram,et al.  Hyperpolarized 3He MR imaging: physiologic monitoring observations and safety considerations in 100 consecutive subjects. , 2008, Radiology.

[10]  G. Parraga,et al.  Mapping and quantifying hyperpolarized 3He magnetic resonance imaging apparent diffusion coefficient gradients. , 2008, Journal of applied physiology.

[11]  Dmitriy A Yablonskiy,et al.  Role of collateral paths in long-range diffusion in lungs. , 2008, Journal of applied physiology.

[12]  F. Korosec,et al.  Functional lung imaging using hyperpolarized gas MRI , 2007, Journal of magnetic resonance imaging : JMRI.

[13]  G. Washko,et al.  Biological lung volume reduction: a new bronchoscopic therapy for advanced emphysema. , 2007, Chest.

[14]  Lawrence Dougherty,et al.  Application of an optical flow method to inspiratory and expiratory lung MDCT to assess regional air trapping: a feasibility study. , 2007, AJR. American journal of roentgenology.

[15]  Dmitriy A Yablonskiy,et al.  Hyperpolarized 3He diffusion MRI and histology in pulmonary emphysema , 2006, Magnetic resonance in medicine.

[16]  F. Venuta,et al.  Bronchoscopic lung volume reduction for end-stage emphysema: report on the first 98 patients. , 2006, Chest.

[17]  Tinsu Pan,et al.  Dynamic ventilation imaging from four-dimensional computed tomography , 2006, Physics in medicine and biology.

[18]  Lawrence Dougherty,et al.  Use of an optical flow method for the analysis of serial CT lung images. , 2006, Academic radiology.

[19]  Thomas Guerrero,et al.  Quantification of regional ventilation from treatment planning CT. , 2005, International journal of radiation oncology, biology, physics.

[20]  G. Snell,et al.  133Xenon ventilation scintigraphy applied to bronchoscopic lung volume reduction techniques for emphysema: relevance of interlobar collaterals , 2005, Internal medicine journal.

[21]  Brett A. Simon,et al.  Non-Invasive Imaging of Regional Lung Function using X-Ray Computed Tomography , 2004, Journal of Clinical Monitoring and Computing.

[22]  S. Newman,et al.  Radionuclide imaging technologies and their use in evaluating asthma drug deposition in the lungs. , 2003, Advanced drug delivery reviews.

[23]  Lawrence Dougherty,et al.  Alignment of CT lung volumes with an optical flow method. , 2003, Academic radiology.

[24]  Hans M. Hertz,et al.  Ultrasonic trapping in capillaries for trace-amount biomedical analysis , 2001 .

[25]  Eric A. Hoffman,et al.  Automatic lung segmentation for accurate quantitation of volumetric X-ray CT images , 2001, IEEE Transactions on Medical Imaging.

[26]  B. Simon,et al.  Distribution of pulmonary ventilation using Xe-enhanced computed tomography in prone and supine dogs. , 2001, Journal of applied physiology.

[27]  Y. Nakano,et al.  Optimized scanning conditions of high resolution CT in the follow-up of pulmonary emphysema. , 1999, Journal of computer assisted tomography.

[28]  P. Paré,et al.  A quantification of the lung surface area in emphysema using computed tomography. , 1999, American journal of respiratory and critical care medicine.

[29]  Eric A. Hoffman,et al.  Xenon-enhanced CT imaging of local pulmonary ventilation , 1996, Medical Imaging.

[30]  Steven S. Beauchemin,et al.  The computation of optical flow , 1995, CSUR.

[31]  N. Morrell,et al.  Collateral ventilation and gas exchange in emphysema. , 1994, American journal of respiratory and critical care medicine.

[32]  L. Hedlund,et al.  Evaluating Lung Density by Computed Tomography , 1983 .

[33]  Takeo Kanade,et al.  An Iterative Image Registration Technique with an Application to Stereo Vision , 1981, IJCAI.

[34]  Berthold K. P. Horn,et al.  Determining Optical Flow , 1981, Other Conferences.

[35]  B Bunow,et al.  Regional ventilatory clearance by xenon scintigraphy: a critical evaluation of two estimation procedures. , 1979, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[36]  R. Traystman,et al.  COLLATERAL VENTILATION IN MAN , 1978, The Lancet.

[37]  W M Thurlbeck,et al.  The resistance of collateral channels in excised human lungs. , 1969, The Journal of clinical investigation.

[38]  D. Pengelly,et al.  Effect of gravity on the distribution of pulmonary ventilation. , 1966, Journal of applied physiology.

[39]  M. Dolovich,et al.  Regional distribution of inspired gas in the lung. , 1966, Journal of applied physiology.