Home Using Hyperpolarized129 Xe MRI to Quantify the Pulmonary Ventilation Distribution
Post
Cancel

Using Hyperpolarized129 Xe MRI to Quantify the Pulmonary Ventilation Distribution

Rationale and Objectives

Ventilation heterogeneity is impossible to detect with spirometry. Alternatively, pulmonary ventilation can be imaged three-dimensionally using inhaled 129 Xe magnetic resonance imaging (MRI). To date, such images have been quantified primarily based on ventilation defects. Here, we introduce a robust means to transform 129 Xe MRI scans such that the underlying ventilation distribution and its heterogeneity can be quantified.

Materials and Methods

Quantitative 129 Xe ventilation MRI was conducted in 12 younger (24.7 ± 5.2 years) and 10 older (62.2 ± 7.2 years) healthy individuals, as well as in 9 younger (25.9 ± 6.4 yrs) and 10 older (63.2 ± 6.1 years) asthmatics. The younger healthy population was used to establish a reference ventilation distribution and thresholds for six intensity bins. These bins were used to display and quantify the ventilation defect region (VDR), the low ventilation region (LVR), and the high ventilation region (HVR).

Results

The ventilation distribution in young subjects was roughly Gaussian with a mean and standard deviation of 0.52 ± 0.18, resulting in VDR = 2.1 ± 1.3%, LVR = 15.6 ± 5.4%, and HVR = 17.4 ± 3.1%. Older healthy volunteers exhibited a significantly right-skewed distribution (0.46 ± 0.20, P = 0.034), resulting in significantly increased VDR (7.0 ± 4.8%, P = 0.008) and LVR (24.5 ± 11.5%, P = 0.025). In the asthmatics, VDR and LVR increased in the older population, and HVR was significantly reduced (13.5 ± 4.6% vs 18.9 ± 4.5%, P = 0.009). Quantitative 129 Xe MRI also revealed altered ventilation heterogeneity in response to albuterol in two asthmatics with normal spirometry.

Conclusions

Quantitative 129 Xe MRI provides a robust and objective means to display and quantify the pulmonary ventilation distribution, even in subjects who have airway function impairment not appreciated by spirometry.

Introduction

The distribution of ventilation is known to be nonuniform in healthy lungs , and this heterogeneity increases with age and disease. Ventilation heterogeneity is impossible to quantify using spirometry because it measures the lung as a single unit and is insensitive to pathology in the small airways—the so-called silent zone. Alternative approaches include using the multiple-breath nitrogen washout (MBNW) test to determine the distribution of specific ventilation (SV) , the lung clearance index (LCI) , or the multiple inert gas elimination technique (MIGET) to quantify the ventilation–perfusion relationship ; however, none of these tests provides spatial information. Alternatively, imaging methods such as computed tomography (CT) delineate spatial changes in lung structures that may allow ventilation abnormalities to be inferred. However, CT does not directly measure ventilation and its radiation dose limits some longitudinal studies.

Recently, magnetic resonance imaging (MRI) techniques have emerged that enable direct detection of inhaled gases, such as oxygen , perfluorinated gases , and hyperpolarized (HP) 3 He . These techniques enable visualization of ventilation defects that have been shown to correlate with airway tone and airway abnormalities . HP 3 He MRI readily depicts regional ventilation heterogeneity in patients with pulmonary obstructive diseases . More recently, 129 Xe gas has emerged as the most promising alternative to address dwindling supplies of 3 He . 129 Xe MRI appears to more readily detect ventilation defects than 3 He MRI and has been used to visualize elimination of ventilation defects after bronchodilator administration .

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Methods

Subjects

Get Radiology Tree app to read full this article<

Image Acquisition

Get Radiology Tree app to read full this article<

Image Analysis

Get Radiology Tree app to read full this article<

Figure 1, (a) 129 Xe MRI as acquired. (b) After correction for B1 inhomogeneity. (c) 1 H thoracic cavity image registered to 129 Xe MRI. (d) Detection of vascular structures within the 1 H image. (e) Segmentation and 1-pixel erosion to create a thoracic cavity mask with vascular structures removed, (f) histogram of 129 Xe intensities within the mask, and (g) 129 Xe histogram after rescaling by the top percentile of all intensities. (h) Binning map generated after applying thresholds. MRI, magnetic resonance imaging.

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Statistical Methods

Get Radiology Tree app to read full this article<

Results

Study Population

Get Radiology Tree app to read full this article<

Distribution of Ventilation in Young Healthy Subjects

Get Radiology Tree app to read full this article<

Figure 2, (a) Rescaled ventilation distribution for the 10 young normal individuals. (b) Average distribution for the 10 subjects has a mean of 0.52 and a standard deviation of 0.18. This distribution was used to define the thresholds and widths of six bins used to quantify and map the ventilation distribution.

Get Radiology Tree app to read full this article<

Effects of Age

Get Radiology Tree app to read full this article<

Figure 3, Examples of 129 Xe-derived ventilation distributions in a healthy younger and older subject. (a) In a 27-year-old healthy subject with an FEV1 of 86%, the 129 Xe ventilation image shows very few ventilation defects. The associated histogram is similar to that of normal young controls, with a mean of 0.54 and an SD of 0.18. (b) In a 58-year-old healthy subject with an FEV1 of 102%, the ventilation image shows areas of ventilation defects (red) and low ventilation (orange). The associated ventilation histogram shifted toward lower values compared to that of normal young controls, with a mean of 0.40 and an SD of 0.20. SD, standard deviation. (Color version of figure is available online.)

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Figure 4, Comparison of ventilation distribution parameters between the YC and OC groups. (a) Ventilation distribution histogram from the OC group (red) is overlaid with that from the YC group (blue). The ventilation distribution in the older healthy subjects shifted toward lower values compared to the younger group. (b) Comparison of ventilation distribution parameters between the young and old groups shows significant differences for all parameters except HVR (* indicates P ≤ 0.05). CV, coefficient of variation; HVR, high ventilation region; LVR, low ventilation region; OC, older control; SD, standard deviation; VDR, ventilation defect region; YC, younger control. (Color version of figure is available online.)

Get Radiology Tree app to read full this article<

Ventilation Distribution in Older and Younger Asthmatics

Get Radiology Tree app to read full this article<

Figure 5, Representative ventilation distributions in a younger asthmatic and an older asthmatic. (a) The younger asthmatic with an FEV1 of 76% exhibits a ventilation image with very few ventilation defects. The associated histogram is similar to that of normal young controls. (b) The older asthmatic with an FEV1 of 53% has a ventilation image with significant areas of ventilation defects (red) and low ventilation (orange). The associated ventilation histogram of the older asthmatic was significantly right skewed compared to that of the normal young controls. (Color version of figure is available online.)

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Figure 6, Comparison of ventilation distributions between the YA and OA groups. (a) Ventilation distribution histogram from the OA group (red) is overlaid with that from the YA group (blue). In the OA group, the distribution is shifted toward lower values compared to the younger asthmatic group. (b) Comparison of ventilation distribution parameters between the YA and the OA groups shows significant differences in all parameters (* indicates P ≤ 0.05). CV, coefficient of variation; HVR, high ventilation region; LVR, low ventilation region; OA, older asthmatic; SD, standard deviation; VDR, ventilation defect region; YA, younger asthmatic. (Color version of figure is available online.)

Get Radiology Tree app to read full this article<

Differences between FEV1 and 129 Xe MRI Ventilation Distribution

Get Radiology Tree app to read full this article<

Figure 7, Comparisons between FEV1 and 129 Xe MRI-derived ventilation distribution in patients with asthma. (a) A patient with normal FEV1 but abnormal 129 Xe MRI. ( b ) A patient with abnormal FEV1 but normal 129 Xe MRI. (c and d) Two patients with moderate asthma with similarly low FEV1 but markedly different ventilation patterns.

Get Radiology Tree app to read full this article<

Ventilation Distribution Before and After Albuterol Treatment

Get Radiology Tree app to read full this article<

Figure 8, Ventilation distribution in a patient with mild intermittent asthma who had positive bronchodilator response to albuterol based on FEV1 criteria. (a) The binning map ( top ) and histogram ( bottom ) before albuterol. (b) The binning map ( top ) and histogram ( bottom ) after albuterol showed a decreased ventilation defect region and low ventilation region, and a distribution matching that of young normal controls after bronchodilator use.

Figure 9, Ventilation distribution in a patient with mild intermittent asthma who did not respond to albuterol based on FEV1 criteria. (a) The binning map ( top ) and histogram ( bottom ) before albuterol treatment. (b) The binning map ( top ) and histogram ( bottom ) after albuterol treatment. The ventilation distribution histogram after albuterol treatment showed decreased VDR but increased LVR at the expense of normally ventilated regions. This may be the result of more normal airways dilating and redistributing ventilation.

Get Radiology Tree app to read full this article<

Discussion

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

Get Radiology Tree app to read full this article<

References

  • 1. Wagner P.D., Laravuso R.B., Uhl R.R., et. al.: Continuous distributions of ventilation-perfusion ratios in normal subjects breathing air and 100 per cent O 2 . J Clin Invest 1974; 54: pp. 54-68.

  • 2. Lewis S.M., Evans J.W., Jalowayski A.A.: Continuous distributions of specific ventilation recovered from inert gas washout. J Appl Physiol Respir Environ Exerc Physiol 1978; 44: pp. 416-423.

  • 3. Simon B.A., Kaczka D.W., Bankier A.A., et. al.: What can computed tomography and magnetic resonance imaging tell us about ventilation?. J Appl Physiol 2012; 113: pp. 647-657.

  • 4. Tzeng Y.S., Lutchen K., Albert M.: The difference in ventilation heterogeneity between asthmatic and healthy subjects quantified using hyperpolarized 3He MRI. J Appl Physiol 2009; 106: pp. 813-822.

  • 5. Verbanck S., Thompson B.R., Schuermans D., et. al.: Ventilation heterogeneity in the acinar and conductive zones of the normal ageing lung. Thorax 2012; 67: pp. 789-795.

  • 6. Wagner P.D., Saltzman H.A., West J.B.: Measurement of continuous distributions of ventilation-perfusion ratios: theory. J Appl Physiol 1974; 36: pp. 588-599.

  • 7. Robinson P.D., Latzin P., Verbanck S., et. al.: Consensus statement for inert gas washout measurement using multiple- and single- breath tests. Eur Respir J 2013; 41: pp. 507-522.

  • 8. Horsley A., Wild J.M.: Ventilation heterogeneity and the benefits and challenges of multiple breath washout testing in patients with cystic fibrosis. Paediatr Respir Rev 2015; 16: pp. 15-18.

  • 9. Kent L., Reix P., Innes J.A., et. al.: Lung clearance index: evidence for use in clinical trials in cystic fibrosis. J Cyst Fibros 2014; 13: pp. 123-138.

  • 10. Horsley A.: Lung clearance index in the assessment of airways disease. Resp Med 2009; 103: pp. 793-799.

  • 11. Aurora P., Gustafsson P., Bush A., et. al.: Multiple breath inert gas washout as a measure of ventilation distribution in children with cystic fibrosis. Thorax 2004; 59: pp. 1068-1073.

  • 12. Edelman R.R., Hatabu H., Tadamura E., et. al.: Noninvasive assessment of regional ventilation in the human lung using oxygen-enhanced magnetic resonance imaging. Nat Med 1996; 2: pp. 1236-1239.

  • 13. Ohno Y., Hatabu H., Takenaka D., et. al.: Dynamic oxygen-enhanced MRI reflects diffusing capacity of the lung. Magn Reson Med 2002; 47: pp. 1139-1144.

  • 14. Sa R.C., Asadi A.K., Theilmann R.J., et. al.: Validating the distribution of specific ventilation in healthy humans measured using proton MR imaging. J Appl Physiol 2014; 116: pp. 1048-1056.

  • 15. Halaweish A.F., Moon R.E., Foster W.M., et. al.: Perfluoropropane gas as a magnetic resonance lung imaging contrast agent in humans. Chest 2013; 144: pp. 1300-1310.

  • 16. Ouriadov A.V., Fox M.S., Couch M.J., et. al.: In vivo regional ventilation mapping using fluorinated gas MRI with an x-centric FGRE method. Magn Reson Med 2015; 74: pp. 550-557.

  • 17. Salerno M., Altes T.A., Mugler J.P., et. al.: Hyperpolarized noble gas MR imaging of the lung: potential clinical applications. Eur J Radiol 2001; 40: pp. 33-44.

  • 18. de Lange E.E., Altes T.A., Patrie J.T., et. al.: Evaluation of asthma with hyperpolarized helium-3 MRI: correlation with clinical severity and spirometry. Chest 2006; 130: pp. 1055-1062.

  • 19. Costella S., Kirby M., Maksym G.N., et. al.: Regional pulmonary response to a methacholine challenge using hyperpolarized 3He magnetic resonance imaging. Respirology 2012; 17: pp. 1237-1246.

  • 20. Kirby M., Svenningsen S., Owrangi A., et. al.: Hyperpolarized 3He and 129Xe MR imaging in healthy volunteers and patients with chronic obstructive pulmonary disease. Radiology 2012; 265: pp. 600-610.

  • 21. Svenningsen S., Kirby M., Starr D., et. al.: What are ventilation defects in asthma?. Thorax 2014; 69: pp. 63-71.

  • 22. Fain S.B., Gonzalez-Fernandez G., Peterson E.T., et. al.: Evaluation of structure-function relationships in asthma using multidetector CT and hyperpolarized He-3 MRI. Acad Radiol 2008; 15: pp. 753-762.

  • 23. Altes T.A., Powers P.L., Knight-Scott J., et. al.: Hyperpolarized 3He MR lung ventilation imaging in asthmatics: preliminary findings. J Magn Reson Imaging 2001; 13: pp. 378-384.

  • 24. Mugler J.P., Altes T.A.: Hyperpolarized 129Xe MRI of the human lung. J Magn Reson Imaging 2013; 37: pp. 313-331.

  • 25. Virgincar R.S., Cleveland Z.I., Kaushik S.S., et. al.: Quantitative analysis of hyperpolarized 129Xe ventilation imaging in healthy volunteers and subjects with chronic obstructive pulmonary disease. NMR Biomed 2013; 26: pp. 424-435.

  • 26. Stewart N.J., Norquay G., Griffiths P.D., et. al.: Feasibility of human lung ventilation imaging using highly polarized naturally abundant xenon and optimized three-dimensional steady-state free precession. Magn Reson Med 2015; 74: pp. 346-352.

  • 27. Kirby M., Svenningsen S., Kanhere N., et. al.: Pulmonary ventilation visualized using hyperpolarized helium-3 and xenon-129 magnetic resonance imaging: differences in COPD and relationship to emphysema. J Appl Physiol 2013; 114: pp. 707-715.

  • 28. Svenningsen S., Kirby M., Starr D., et. al.: Hyperpolarized 3He and 129Xe MRI: differences in asthma before bronchodilation. J Magn Reson Imaging 2013; 38: pp. 1521-1530.

  • 29. Woodhouse N., Wild J.M., Paley M.N., et. al.: Combined helium-3/proton magnetic resonance imaging measurement of ventilated lung volumes insmokers compared to never-smokers. J Magn Reson Imaging 2005; 21: pp. 365-369.

  • 30. Kirby M., Heydarian M., Svenningsen S., et. al.: Hyperpolarized 3He magnetic resonance functional imaging semiautomated segmentation. Acad Radiol 2012; 19: pp. 141-152.

  • 31. He M., Kaushik S.S., Robertson S.H., et. al.: Extending semiautomatic ventilation defect analysis for hyperpolarized (129)Xe ventilation MRI. Acad Radiol 2014; 21: pp. 1530-1541.

  • 32. Hahn A.D., Cadman R.V., Sorkness R.L., et. al.: Redistribution of inhaled hyperpolarized He3 gas during breath-hold differs by asthma severity. J Appl Physiol 2016; 120: pp. 526-536. jap 00197 2015

  • 33. Ebner L., He M., Virgincar R.S., et. al.: Hyperpolarized 129Xenon MRI to quantify regional ventilation differences in mild to moderate asthma: a prospective comparison between semi-automated ventilation defect percentage calculation and pulmonary function tests. Invest Radiol 2016; In Press

  • 34. He M., Robertson S.H., Kaushik S.S., et. al.: Dose and pulse sequence considerations for hyperpolarized (129)Xe ventilation MRI. Magn Reson Imaging 2015; 33: pp. 877-885.

  • 35. Fulambarker A., Copur A.S., Javet A., et. al.: Reference values for pulmonary function in Asian Indians living in the United States. Chest 2004; 126: pp. 1225-1233.

  • 36. Kirby M., Mathew L., Wheatley A., et. al.: Chronic obstructive pulmonary disease: longitudinal hyperpolarized 3He MR imaging. Radiology 2010; 256: pp. 280-289.

  • 37. Hamerly G., Elkan C.: Learning the K in K-means. NIPS 2003; 17:

  • 38. MacKay D.J.C.: Information theory, inference, and learning algorithms.2004.Cambridge University PressCambridge, UK, New York Reprinted with corrections. ed

  • 39. Deninger A.J., Mansson S., Petersson J.S., et. al.: Quantitative measurement of regional lung ventilation using He-3 MRI. Magn Reson Med 2002; 48: pp. 223-232.

  • 40. Emami K., Kadlecek S.J., Woodburn J.M., et. al.: Improved technique for measurement of regional fractional ventilation by hyperpolarized 3He MRI. Magn Reson Med 2010; 63: pp. 137-150.

  • 41. Horn F.C., Deppe M.H., Marshall H., et. al.: Quantification of regional fractional ventilation in human subjects by measurement of hyperpolarized 3He washout with 2D and 3D MRI. J Appl Physiol 2014; 116: pp. 129-139.

  • 42. Hamedani H., Clapp J.T., Kadlecek S.J., et. al.: Regional fractional ventilation by using multibreath wash-in 3He MR imaging. Radiology 2016; 279: pp. 917-924. 150495

  • 43. Sa R.C., Cronin M.V., Henderson A.C., et. al.: Vertical distribution of specific ventilation in normal supine humans measured by oxygen-enhanced proton MRI. J Appl Physiol 2010; 109: pp. 1950-1959.

  • 44. Sheikh K., Paulin G.A., Svenningsen S., et. al.: Pulmonary ventilation defects in older never-smokers. J Appl Physiol 2014; 117: pp. 297-306.

  • 45. Janssens J.P., Pache J.C., Nicod L.P.: Physiological changes in respiratory function associated with ageing. Eur Respir J 1999; 13: pp. 197-205.

  • 46. Cardus J., Burgos F., Diaz O., et. al.: Increase in pulmonary ventilation-perfusion inequality with age in healthy individuals. Am J Respir Crit Care Med 1997; 156: pp. 648-653.

  • 47. Heckscher T., Bass H., Oriol A., et. al.: Regional lung function in patients with bronchial asthma. J Clin Invest 1968; 47: pp. 1063-1070.

  • 48. Gompelmann D., Eberhardt R., Herth F.J.: Collateral ventilation. Respiration 2013; 85: pp. 515-520.

  • 49. Macklem P.T.: Airway obstruction and collateral ventilation. Physiol Rev 1971; 51: pp. 368-436.

  • 50. Kaminsky D.A., Bates J.H., Irvin C.G.: Effects of cool, dry air stimulation on peripheral lung mechanics in asthma. Am J Respir Crit Care Med 2000; 162: pp. 179-186.

  • 51. Moore W.C., Meyers D.A., Wenzel S.E., et. al.: Identification of asthma phenotypes using cluster analysis in the severe asthma research program. Am J Respir Crit Care Med 2010; 181: pp. 315-323.

  • 52. Despas P.J., Leroux M., Macklem P.T.: Site of airway obstruction in asthma as determined by measuring maximal expiratory flow breathing air and a helium-oxygen mixture. J Clin Invest 1972; 51: pp. 3235-3243.

  • 53. Lagerstrand L., Skedinger M., Ihre E., et. al.: Spirometry and ventilation-perfusion inequality in patients with mild allergic asthma before and during the pollen season. Clin Physiol 1995; 15: pp. 355-364.

  • 54. Cardus J., Burgos F., Diaz O., et. al.: Increase in pulmonary ventilation-perfusion inequality with age in healthy individuals. Am J Respir Crit Care Med 1997; 156: pp. 648-653.

  • 55. Macleod K.A., Horsley A.R., Bell N.J., et. al.: Ventilation heterogeneity in children with well controlled asthma with normal spirometry indicates residual airways disease. Thorax 2009; 64: pp. 33-37.

  • 56. Kraemer R., Blum A., Schibler A., et. al.: Ventilation inhomogeneities in relation to standard lung function in patients with cystic fibrosis. Am J Resp Crit Care 2005; 171: pp. 371-378.

This post is licensed under CC BY 4.0 by the author.