Projection methods for producing two-dimensional images from three-dimensional data

• US 5,233,299 A
• Filed: 03/25/1991
• Issued: 08/03/1993
• Est. Priority Date: 03/25/1991
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Dumoulin, Charles L., Adams, William J., Souza, Steven P.
• Primary Examiner(s): ARANA, LOUIS M
• Application Number:
  US07/674,476
• Time in Patent Office: 862 Days
• Field of Search: 324/300, 324/307, 324/309, 324/312, 382/41, 382/50, 382/51, 382/52, 382/54
• US Class Current: 324/307
• CPC Class Codes: G01R 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography

Abstract

A method of collecting three-dimensional magnetic resonance (MR) fluid flow images from a volume of a subject and constructing a high contrast low noise two-dimensional image therefrom is accomplished by statistical calculation of voxel values along projection lines cast through a three-dimensional data volume obtained from three-dimensional MR angiography techniques, and converting the data to projection images by summing the weighted differences from the projection average of data for each voxel along a projection ray. The data are then normalized and repeated for all projection rays to obtain a set of projection values which are displayed on a two-dimensional display device.

Claims

1. A method of displaying a two-dimensional (2D) projection image of desired structures of a subject from collected three-dimensional (3D) image data of a volume of a subject comprising the steps of:

a) acquiring a 3D data set having a plurality of entries, each entry being a value corresponding to at least one physical parameter representative of a voxel within said volume;

b) selecting a statistical order k;

c) choosing a viewing angle from which to view said volume;

d) determining a set of intersected voxels which are intersected by a selected imaginary projection ray passing through said volume at the viewing angle and determining N intersected data set entries V_i corresponding to the intersected voxels;

e) calculating an average V and a standard deviation σ

from the N intersected data set entries V_i ;

f) calculating a projection value P_k from the N intersected data set entries V_i according to the equation;

##EQU2## g) repeating steps "d"-"f" for a plurality of parallel imaginary projection rays at the viewing angle covering said volume;

h) transferring the projection values P_k to a two-dimensional display device;

i) displaying a two-dimensional image created from the projection values P_k on the two dimensional display device for analysis and interpretation;

j) increase the value of the statistical order k and repeat steps "d"-"i" if a greater contrast of said structures in the projection image is desired; and

k) decrease the value of the statistical order k and repeat steps "d"-"i" if a greater signal-to-noise ratio of said structures in the projection image is desired.

2. The method of displaying a 2D projection image as recited in claim 1 wherein the 3D data set is acquired by phase contrast magnetic resonance imaging techniques.

3. The method of displaying a 2D projection image as recited in claim 1 wherein the 3D data set is acquired by time-of-flight magnetic resonance flow imaging techniques.

4. The method of displaying a 2D projection image as recited in claim 1 further including the step of varying the order of the statistic for a predetermined three-dimensional data set to produce images with differing contrast of said structures of said subject imaged.

5. The method of displaying a 2D projection image as recited in claim 1 wherein the 3D data set is acquired by magnetic resonance imaging techniques used to produce images of substantially stationary tissue.

6. The method of displaying a 2D projection image as recited in claim 1 wherein the 3D data set is acquired by tomographic imaging techniques.

7. The method of displaying a 2D projection image as recited in claim 1 wherein the 3D data set is acquired by magnetic resonance imaging techniques.