Measurements of regional alveolar oxygen pressure using hyperpolarized 3He MRI.

RATIONALE AND OBJECTIVES The aim of this work is to review hyperpolarized (HP) helium-3 (3He) magnetic resonance imaging (MRI) methods to measure regional alveolar oxygen partial pressure (P(A)O2) and oxygen depletion rate (R) in the lung. We point out limitations of the methods and suggest improvements to increase their accuracy. MATERIALS AND METHODS P(A)O2 and R can be extracted from series of HP gas images acquired during breath hold by making use of the depolarizing effect of oxygen on HP gas. To separate oxygen-induced depolarization from other depolarizing effects, several techniques can be used. We review currently used techniques and point out their advantages and limitations. RESULTS We show that the precision of oxygen measurements depends on a variety of parameters and can vary within the measurement volume. Accuracy of the measurement also can be influenced by diffusion of oxygen and polarized 3He and generally is different for single-slice and multislice measurements. We present numerical simulations, phantom data, and in vivo data for illustration. CONCLUSION HP 3He MRI is a noninvasive, nonionizing, and repeatable imaging method that allows for quantitative analysis of lung function. The current techniques for measuring P(A)O2 have the potential to deliver clinically relevant functional images.

[1]  M. Schnall,et al.  Detection and localization of pulmonary air leaks using laser‐polarized 3He MRI , 2000 .

[2]  H. Kauczor,et al.  Elucidation of structure–function relationships in the lung: contributions from hyperpolarized 3helium MRI , 2002, Clinical physiology and functional imaging.

[3]  Eric A Hoffman,et al.  Subsecond multisection CT of regional pulmonary ventilation. , 2002, Academic radiology.

[4]  R E Lenkinski,et al.  Pulmonary perfusion: respiratory-triggered three-dimensional MR imaging with arterial spin tagging--preliminary results in healthy volunteers. , 1999, Radiology.

[5]  H. Gudbjartsson,et al.  The rician distribution of noisy mri data , 1995, Magnetic resonance in medicine.

[6]  T. Jones,et al.  Quantification of regional V/Q ratios in humans by use of PET. I. Theory. , 1989, Journal of applied physiology.

[7]  A. Caprihan,et al.  Imaging obstructed ventilation with NMR using inert fluorinated gases. , 2000, Journal of applied physiology.

[8]  John Palmer,et al.  Lung ventilation/perfusion SPECT in the artificially embolized pig. , 2002, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[9]  Gaetano G. Galletti,et al.  Alterations in regional ventilation, perfusion, and shunt after smoke inhalation measured by PET. , 2002, Journal of applied physiology.

[10]  Tilo Winkler,et al.  Topographical distribution of pulmonary perfusion and ventilation, assessed by PET in supine and prone humans. , 2002, Journal of applied physiology.

[11]  J. Shrager,et al.  A small animal model of regional alveolar ventilation using HP 3He MRI1. , 2004, Academic radiology.

[12]  H. Kauczor,et al.  Assessment of a single‐acquisition imaging sequence for oxygen‐sensitive 3He‐MRI , 2002, Magnetic resonance in medicine.

[13]  B J Whipp,et al.  Dynamics of pulmonary gas exchange. , 1987, Circulation.

[14]  Peter Bachert,et al.  Nuclear magnetic resonance imaging of airways in humans with use of hyperpolarized 3He , 1996, Magnetic resonance in medicine.

[15]  Cates,et al.  Relaxation of spins due to field inhomogeneities in gaseous samples at low magnetic fields and low pressures. , 1988, Physical review. A, General physics.

[16]  M Salerno,et al.  Hyperpolarized noble gas MR imaging of the lung: potential clinical applications. , 2001, European journal of radiology.

[17]  N Weiler,et al.  Quantification of regional intrapulmonary oxygen partial pressure evolution during apnea by (3)He MRI. , 1999, Journal of magnetic resonance.

[18]  T. Jones,et al.  Quantification of regional V/Q ratios in humans by use of PET. II. Procedure and normal values. , 1989, Journal of applied physiology.

[19]  Middleton,et al.  Nuclear relaxation of 3He in the presence of O2. , 1995, Physical review. A, Atomic, molecular, and optical physics.

[20]  T. Matsumoto,et al.  Dynamic pulmonary SPECT of xenon-133 gas washout. , 1996, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[21]  F D Thomas,et al.  Density patterns in the normal lung as determined by computed tomography. , 1980, Radiology.

[22]  Peter Magnusson,et al.  Quantitative measurement of regional lung ventilation using 3He MRI , 2002, Magnetic resonance in medicine.

[23]  Barton,et al.  Gaseous 3He-3He magnetic dipolar spin relaxation. , 1993, Physical review. A, Atomic, molecular, and optical physics.

[24]  H C Charles,et al.  Human lung air spaces: potential for MR imaging with hyperpolarized He-3. , 1996, Radiology.

[25]  R. Henkelman Measurement of signal intensities in the presence of noise in MR images. , 1985, Medical physics.

[26]  M. Paley,et al.  3D volume‐localized pO2 measurement in the human lung with 3He MRI , 2005, Magnetic resonance in medicine.

[27]  Dmitriy A Yablonskiy,et al.  Magnetization tagging decay to measure long‐range 3He diffusion in healthy and emphysematous canine lungs , 2004, Magnetic resonance in medicine.

[28]  R. Rizi,et al.  Single‐acquisition sequence for the measurement of oxygen partial pressure by hyperpolarized gas MRI , 2004, Magnetic resonance in medicine.

[29]  A clinical comparison between Technegas SPECT, CT, and pulmonary function tests in patients with emphysema. , 1997, Radiation medicine.

[30]  John S Leigh,et al.  Pulmonary ventilation and perfusion scanning using hyperpolarized helium‐3 MRI and arterial spin tagging in healthy normal subjects and in pulmonary embolism and orthotopic lung transplant patients , 2002, Magnetic resonance in medicine.

[31]  J Hildebrandt,et al.  Determination of regional ventilation and perfusion in the lung using xenon and computed tomography. , 2001, Journal of applied physiology.

[32]  R. Rizi,et al.  Determination of regional VA/Q by hyperpolarized 3He MRI , 2004, Magnetic resonance in medicine.