Ventilation distribution in rats: Part 2 – A comparison of electrical impedance tomography and hyperpolarised helium magnetic resonance imaging
Hyperpolarised helium MRI (He3 MRI) is a new technique that enables imaging of the air distribution within the lungs. This allows accurate determination of the ventilation distribution in vivo. The technique has the disadvantages of requiring an expensive helium isotope, complex apparatus and moving the patient to a compatible MRI scanner. Electrical impedance tomography (EIT) a non-invasive bedside technique that allows constant monitoring of lung impedance, which is dependent on changes in air space capacity in the lung. We have used He3MRI measurements of ventilation distribution as the gold standard for assessment of EIT.
Seven rats were ventilated in supine, prone, left and right lateral position with 70% helium/30% oxygen for EIT measurements and pure helium for He3 MRI. The same ventilator and settings were used for both measurements. Image dimensions, geometric centre and global in homogeneity index were calculated.
EIT images were smaller and of lower resolution and contained less anatomical detail than those from He3 MRI. However, both methods could measure positional induced changes in lung ventilation, as assessed by the geometric centre. The global in homogeneity index were comparable between the techniques.
EIT is a suitable technique for monitoring ventilation distribution and inhomgeneity as assessed by comparison with He3 MRI.
- Milic-Emili, J, Henderson, JA, Dolovich, MB, Trop, D, Kaneko, K (1966) Regional distribution of inspired gas in the lung. J Appl Physiol 21: pp. 749-759
- Moller, HE, Chen, XJ, Saam, B, Hagspiel, KD, Johnson, GA, Altes, TA, de Lange, EE, Kauczor, HU (2002) MRI of the lungs using hyperpolarized noble gases. Magn Reson Med 47: pp. 1029-1051 CrossRef
- Ruppert, K, Brookeman, JR, Hagspiel, KD, Mugler, JP (2000) Probing lung physiology with xenon polarization transfer contrast (XTC). Magn Reson Med 44: pp. 349-357 CrossRef
- Crawford, AB, Makowska, M, Paiva, M, Engel, LA (1985) Convection- and diffusion-dependent ventilation maldistribution in normal subjects. J Appl Physiol 59: pp. 838-846
- Forkert, L, Wood, LD, Cherniack, RM (1975) Effect of gas density on dynamic pulmonary compliance. J Appl Physiol 39: pp. 906-910
- Dunster, KR, Friese, M, Fraser, JF, Cowin, GJ, Schibler, A (2012) Ventilation distribution in rats: Part I - The effect of gas composition as measured with electrical impedance tomography. BioMedical Engineering OnLine 11: pp. 64 CrossRef
- Bodenstein, M, David, M, Markstaller, K (2009) Principles of electrical impedance tomography and its clinical application. Crit Care Med 37: pp. 713-724 CrossRef
- Rooney, D, Friese, M, Fraser JF, KRD, Schibler, A (2009) Gravity-dependent ventilation distribution in rats measured with electrical impedance tomography. Physiol Meas 30: pp. 1075-1085 CrossRef
- Hedlund, LW, Cofer, GP, Owen, SJ, Allan Johnson, G (2000) MR-compatible ventilator for small animals: computer-controlled ventilation for proton and noble gas imaging. Magn Reson Imaging 18: pp. 753-759 CrossRef
- Hahn, G, Dudykevych, T, Frerichs, I, Hellige, G (2002) EIT System for clinical and space applications. Proceedings of the 2nd European Medical and Biological Engineering Conference, Vienna, Austria, Dec 04-08, 2002 IFMBE Proceedings Series 3: pp. 110-111
- Rasband W: ImageJ. , Bethesda, Maryland, USA; 2009. [National Institutes of Health] http://rsbinfonihgov/ij/
- Frerichs, I, Dargaville, PA, van Genderingen, H, Morel, DR, Rimensberger, PC (2006) Lung volume recruitment after surfactant administration modifies spatial distribution of ventilation. Am J Respir Crit Care Med 174: pp. 772-779 CrossRef
- Zhao, Z, Moller, K, Steinmann, D, Frerichs, I, Guttmann, J (2009) Evaluation of an electrical impedance tomography-based Global Inhomogeneity Index for pulmonary ventilation distribution. Intensive Care Med 35: pp. 1900-1906 CrossRef
- Hahn, G, Dudykevych, T, Frerichs, I, Hellige, G (2002) EIT System for clinical and space applications. Proc 2nd Eur Med Biol Eng Conf 3: pp. 110-111
- Gibson, A, Bayford, R, Holder, D (2000) Two-dimensional finite element modelling of the neonatal head. Physiol Meas 21: pp. 45-52 CrossRef
- Adler, A, Amyot, R, Guardo, R, Bates, JH, Berthiaume, Y (1997) Monitoring changes in lung air and liquid volumes with electrical impedance tomography. J Appl Physiol 83: pp. 1762-1767
- Wrigge, H, Zinserling, J, Muders, T, Varelmann, D, Gunther, U, von der Groeben, C, Magnusson, A, Hedenstierna, G, Putensen, C (2008) Electrical impedance tomography compared with thoracic computed tomography during a slow inflation maneuver in experimental models of lung injury. Crit Care Med 36: pp. 903-909 CrossRef
- Ventilation distribution in rats: Part 2 – A comparison of electrical impedance tomography and hyperpolarised helium magnetic resonance imaging
- Open Access
- Available under Open Access This content is freely available online to anyone, anywhere at any time.
BioMedical Engineering OnLine
- Online Date
- September 2012
- Online ISSN
- BioMed Central
- Additional Links
- Electrical impedance tomography
- Hyperpolarized helium magnetic resonance lmaging
- Ventilation distribution
- Functional lung imaging
- Author Affiliations
- 1. Paediatric Critical Care Research Group, Paediatric Intensive Care Unit, Mater Children’s Hospital, South Brisbane, 4101, QLD, Australia
- 2. Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
- 4. Medical Engineering, Queensland University of Technology, Brisbane, QLD, Australia
- 3. Centre for Advanced Imaging, The University of Queensland, Brisbane, QLD, Australia