Determination of the arterial input function in dynamic contrast-enhanced MRI

• US 6,546,275 B2
• Filed: 06/25/2001
• Issued: 04/08/2003
• Est. Priority Date: 06/25/2001
• Status: Expired due to Term

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Carroll, Timothy J.
• Primary Examiner(s): Vo, Hieu T.
• Application Number:
  US09/888,973
• Publication Number:
  US 20030045791A1
• Time in Patent Office: 652 Days
• Field of Search: 600/419, 600/420, 600/410, 600/411, 600/415, 600/407, 600/408, 600/425, 600/427
• US Class Current: 600/419
• CPC Class Codes: G01R 33/281 Means for the use of in vitro contrast agents G01R33/282 takes precedence; involving use of a contrast agent in MR imaging G01R33/5601; in vivo contrast agents A61K49/0002
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography

Abstract

A contrast-enhanced MRI time course study of the brain is performed and images are produced which indicate hemodynamic parameters such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). An arterial input function (AIF) required to quantitatively measure the hemodynamic parameters is automatically produced.

Claims

1. A method for producing a magnetic resonance image (MRI) of a hemodynamic parameter in tissues, the steps comprising:

a) performing a contrast-enhanced magnetic resonance study of the tissues in which a series of MRI images are acquired as a contrast agent flows through the tissues;

b) forming a time course NMR image data set with the acquired MRI images, the time course NMR image data set providing a plurality of time course voxel studies which indicate the magnitude of NMR signals produced during the study at voxels throughout the tissues;

c) automatically producing an, arterial input function (AIF) by selecting one of the time course voxel studies based on an analysis of the NMR signals produced during the study;

d) calculating a hemodynamic parameter for each voxel using the corresponding time course voxel study and the AIF produced in step c); and

e) producing an image in which the brightness of pixels therein is modulated by the hemodynamic parameters calculated in step d).

2. The method as recited in claim 1 in which the hemodynamic parameter is blood flow.

3. The method as recited in claim 1 in which the hemodynamic parameter is blood volume.

4. The method as recited in claim 1 in which the hemodynamic parameter is mean transit time.

5. The method as recited in claim 1 in which the arterial input function (AIF) is produced by selecting one of the time course voxel studies having the maximum signal loss as the contrast agent flows through the voxel.

6. The method as recited in claim 1 in which step c) is performed by:

i) calculating a mean signal value for each time course voxel study prior to arrival of the contrast agent;

ii) determining a set of candidate time course voxel studies by filtering out time course voxel studies that are not arterial;

iii) calculating signal loss below the mean signal value for each candidate time course voxel study; and

iv) selecting a time course voxel study having the maximum signal loss.

7. The method as recited in claim 6 in which step ii) includes:

filtering out time course voxel studies which have a mean signal value below a selected value.

8. The method as recited in claim 6 in which step ii) includes:

filtering out time course voxel studies which indicate by the timing of their signal loss that they are venous voxels.

9. The method as recited in claim 1 which includes determining a peak time in the AIF produced in step c) which indicates maximum contrast agent signal modulation, and the calculations in step d) employ the peak time to calculate the hemodynamic parameter.

10. In a contrast enhanced magnetic resonance image study in which a series of images are acquired as a contrast agent flows through a region of interest, a method for automatically producing a signal indicative of the change in NMR signal in an artery which supplies blood to the region of interest, the steps comprising:

a) arranging the acquired images in order to form time course voxel studies which indicate the magnitude of NMR signals produced in each voxel in the region of interest during the study; and

b) selecting one of the time course voxel studies based on an analysis of the NMR signals produced in said voxels, said analysis including steps which detect characteristics produced by arterial blood flow through the voxels.

11. The method as recited in claim 10 in which the analysis in step b) includes:

i) filtering out time course voxel studies which do not exhibit a significant change in NMR signal magnitude when the contrast agent arrives in the tissues;

ii) filtering out time course voxel studies which exhibit a change in NMR signal magnitude a significant time after the first arrival of the contrast agent in the tissues; and

iii) selecting from the remaining time course voxel studies that time course voxel study which exhibits the most change in NMR signal magnitude when the contrast agent arrives.