IMAGING TECHNIQUE

• US 20100145186A1
• Filed: 04/18/2008
• Published: 06/10/2010
• Est. Priority Date: 05/03/2007
• Status: Active Grant

• Current Assignee: Bioxydyn Limited
• Original Assignee: University of Manchester
• Inventors: McGrath, Deirdre, Parker, Geoffrey
• Granted Patent: US 8,255,036 B2
• Time in Patent Office: Days
• US Class Current: 600/420
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/0813 Measurement of pulmonary parameters by tracers, e.g. radioactive tracers
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: G01R 33/50 based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
• CPC Class Codes: G01R 33/5601 involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent
• CPC Class Codes: G01R 33/56341 Diffusion imaging
• CPC Class Codes: G01R 33/56366 Perfusion imaging
• CPC Class Codes: Y10T 436/24 Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry

Abstract

The present invention relates to a method of characterising lung function in a subject in need of such characterisation. The method comprises performing an imaging technique, on a voxel defined within a lung space of interest. Image data is generated over a time period during which the subject inhales gases with at least two different partial pressures of a paramagnetic gas. A compartmental model algorithm is applied to the image data generated for the voxel to provide information on ventilation, diffusion and perfusion of a lung. The paramagnetic gas is preferably Oxygen. The imaging technique is preferably Oxygen Enhanced Magnetic Resonance Imaging (OE-MRI).

Claims

1-21. -21. (canceled)

22. A method of characterising lung function in a subject in need of such characterisation comprising:

performing an imaging technique, on a voxel defined within a lung space of interest,

wherein image data is generated over a time period during which the subject inhales gases with at least two different partial pressures of a paramagnetic gas; and

applying a compartmental model algorithm to the image data generated for the voxel to provide information on ventilation, diffusion and perfusion of a lung.

23. A method according to claim 22 wherein the imaging technique is Oxygen-Enhanced Magnetic Resonance Imaging (OE-MRI) and the paramagnetic gas is oxygen.

24. The method of claim 22 wherein the lung space is divided into a matrix of voxels and OE-MRI data is generated for each voxel.

25. The method of claim 23 wherein OE-MRI data generated while the subject first inhales a first gas with a partial pressure of oxygen between 0% and 35% oxygen;

then breathes a second gas with a partial pressure of oxygen between 45% and 100% oxygen; and

finally inhales the first gas again.

26. The method of claim 25 wherein the first gas is air and the second gas is 100% oxygen.

27. The method according to claim 22 wherein techniques are applied to improve image registration to ensure that the imaging technique is conducted on the same voxel over time.

28. The method according to claim 22 wherein the compartmental model algorithm is a two-compartment model based on physiological parameters for rate of ventilation of the lungs, oxygen diffusion across alveoli and pulmonary blood flow.

29. The method according to claim 28 wherein the compartmental model algorithm calculates the combined oxygen concentration of a second compartment comprising the alveolus membrane, interstitial space between the membrane and pulmonary capillaries and the plasma within the capillaries (C_p).

30. The method according to claim 28 wherein the compartmental model algorithm calculates the fractional volume of blood plasma and tissue water per MRI visible tissue (V_p)).

31. The method according to claim 28 wherein the compartmental model algorithm calculates diffusing capacity of the alveolar membrane (K_ox).

32. The method according to claim 28 wherein the compartmental model algorithm calculates E, the extraction fraction of oxygen from the tissue water and capillaries, and F_b the rate of blood flow in the capillaries.

33. The method according to claim 28 wherein the compartmental model algorithm calculates the time to achieve maximum concentration of oxygen (CA) in the alveolus space, a parameter of the oxygen input function CA.

34. The method according to claim 28 wherein the algorithm is based on the equations developed by Kety and published in Kety, SS (1951) Pharmacological Reviews. 3:

1-41.

35. The method according to claim 28 wherein the algorithm is:

36. The method according to claim 28 wherein the compartmental model or algorithm is varied to incorporate alternative terminology or a different number of compartments, while still adhering to the basic principles underlying the use of compartmental modelling of freely-diffusible tracers based on the equations developed by Kety and published in Kety, S S (1951) Pharmacological Reviews. 3:

1-41.

37. The methods according to claim 22 wherein the algorithm is a distributed parameter model, according to principles described in Johnson J A, Wilson T A. A model for capillary exchange. Am J Physiol 1966;

210(6);

1299-1303.

38. The use of the method according to claim 22 to evaluate lung function in humans or animals for either diagnostic or prognostic purposes or for therapeutic development.

39. A computer apparatus for generating data concerning lung function, the apparatus comprising:

a memory storing processor readable instructions; and

a processor configured to read and execute instructions stored in said memory;

wherein said processor readable instructions comprise instructions controlling said processor to apply a compartmental model algorithm to the image data defined by claim 22,

wherein the compartmental model algorithm is a two-compartment model based on physiological parameters for rate of ventilation of the lungs, oxygen diffusion across alveoli and pulmonary blood flow.

40. A carrier medium carrying computer readable program code configured to cause a computer to carry out a method of applying a compartmental model algorithm to the image data defined by claim 22, wherein the compartmental model algorithm is a two-compartment model based on physiological parameters for rate of ventilation of the lungs, oxygen diffusion across alveoli and pulmonary blood flow.