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A DYNAMIC 3D BILATERAL BREAST ACQUISITION METHOD IN MRI

IP.com Disclosure Number: IPCOM000124120D
Publication Date: 2005-Apr-08

Publishing Venue

The IP.com Prior Art Database

Abstract

In one embodiment, a dynamic 3D bilateral breast acquisition method in MRI uses a very short non-selective RF pulse (100 usec), an asymmetric zero-filling technique in the slice direction, and segmented acquisitions using the SPECIAL inversion pulse. The sequence utilizes a very short non-selective RF pulse to excite the whole volume in sagittal orientation. The non-selective RF pulse excites a large whole volume beyond the region of interests, thus the slab profile is perfectly uniform across the bilateral imaging volume including the profile around the axillae regions of the breasts. The benefit of uniform slab profile is that small lesions that are located at the volume edges can also be detected with the same sensitivity as those located at the center of the volume.

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A DYNAMIC 3D BILATERAL BREAST ACQUISITION METHOD IN MRI

FIELD OF THE INVENTION

[0001]               This invention relates generally, to volumetric breast acquisition methods and more particularly to, a dynamic 3D bilateral breast acquisition method in MRI.

BACKGROUND OF THE INVENTION

[0002]                3D bilateral breast acquisition using contrast-enhanced MR imaging technique has been used clinically for evaluating small breast lesions.  These lesions are usually embedded in the fat tissue of the breasts.  Conventional fat suppression techniques have been used to acquire 3D bilateral breast acquisitions such as using a spectrally selective inversion pulse to null the fat signal.  However, applying the conventional technique results in non-homogeneous fat suppression of the breasts.

[0003]               Furthermore, the conventional technique produces non-uniform slab profile that limits the examination at the volume edges such as the axillae regions of the breast. Therefore, it would be advantageous to develop an ultra-fast whole volume 3D bilateral breast acquisition technique that provides homogeneous fat suppression and uniform slab profile, and thus uniform tissue contrast across the 3D imaging volume, that is suitable for dynamic contrast-enhanced MRI studies.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]                 FIG. 1 shows a typical 3D fast spoiled gradient echo sequence that is used for contrast enhanced 3D high-resolution imaging. The RF excitation is selective, that is, a slice select gradient (S1) and refocusing pulse (S2) must be played out.  The RF pulse results in low excitation slab profile at the edges and results in long scan time.

[0005]                FIG. 2 shows a proposed 3D imaging acquisition that uses an ultra-short non-selective RF pulse to excite the whole volume for sagittal bilateral breast acquisition.  No slice select gradient is played out during RF excitation. Because no slice select gradients are played out, the RF excites the large imaging volume and thus the slab profile is uniform across the bilateral breast imaging volume.  The non-selective RF pulse also does not result in slab wrap because there is no tissue at the very edges. Because of the short RF duration, the echo time (TE) and the repetition time (TR) are shorter than the conventional method, thus shortening the scan time as well.

[0006]                  FIG. 3 shows a 3D bilateral breast acquisition using a non-selective RF pulse to excite the whole sagittal volume. This RF pulse is very short and excites a large imaging volume, thus results in uniform slab profile within the breast imaging volume of interest. This RF pulse also does not cause a slab wrap for bilateral acquisition.

[0007]                FIG. 4 shows a proposed method using the partial zero filling in the slice direction and segmented sequential scheme using spectrally selective inversion pulse (SPECIAL) to uniformly suppress the fat signal. After applying the partial zero filling, a SPECIAL inversion pulse is applied followed by only m Kz lines (instea...