	US 7,395,108 B2
	System for concurrent MRI imaging and magnetic field homogeneity measurement
Vinai Roopchansingh, 919 Glenview Ave., Apt. 2, Milwaukee, Wis. 53213 (US); Robert W. Cox, 8700 Broadmoor Dr., Bethesda, Md. 20817 (US); Andrzej Jesmanowicz, 11170 W. Meinecke Ave., Wauwatosa, Wis. 53226 (US); and James S. Hyde, S42 W34076 Hidden Valley, Dousman, Wis. 53118 (US)
Filed on May 12, 2004, as Appl. No. 10/843,940.
Claims priority of provisional application 60/469958, filed on May 13, 2003.
Prior Publication US 2004/0254449 A1, Dec. 16, 2004
Int. Cl. A61B 5/05 (2006.01); G01V 3/00 (2006.01)

U.S. Cl. 600—410 [324/307]

12 Claims

1. An MRI acquisition method comprising the steps of:

(a) placing a subject in a polarizing magnetic field;

(b) applying an RF excitation pulse to the subject; and

(c) acquiring concurrent magnetic field map data and image data from echoes of the same RF excitation pulse, the magnetic field map data and image data providing data at a plurality of points over an area of the subject; wherein the magnetic field maps are comprised of at least two parallel and spaced apart, doubly-sampled lines of k-space data;

whereby differences between geometric distortions in the image data and measurements of the geometric distortions by the magnetic field map resulting from different pulse sequences are suppressed and spatial mis-registration and time shifts between the magnetic field map and the image data are reduced.