Browse Prior Art Database

Publication Date: 2015-Apr-01
Document File: 6 page(s) / 153K

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The disclosed invention provides a technique for correcting intensity inhomogeneities in a particular case of magnetic resonance (MR) images with very flat contrast. An example of such MR case with flat contrast is that proposed for visualization of bone tissue. The technique includes an inhomogeneity correction algorithm. The algorithm includes information about those tissue regions that are required to estimate unwanted intensity modulation.

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The present invention relates generally to magnetic resonance (MR) imaging and more particularly to a technique for correcting intensity inhomogeneities in MR images with very flat contrast.

Intensity inhomogeneity is an intrinsic limitation of magnetic resonance (MR) imaging. Such inhomogeneity of intensity is due to use of local receive coils. Due to combined sensitivity profiles of different coil elements, intensity of final images shows low-frequency variations that impede proper operation of post-processing operations, such as, segmentation.

There are several conventional techniques known in the art that provides intensity inhomogeneity correction.

Among several conventional techniques, certain conventional techniques rely on external information about coil sensitivities, for example, a calibration scan, whereas, certain other conventional techniques rely only on acquired image. However, the conventional techniques relying on external data requires acquiring such external data. Furthermore, when such data does not accurately match acquisition properties of scene to be corrected, for example, due to patient motion, artifacts are introduced in results.

On the other hand, conventional techniques relying solely on image to be corrected itself are limited by assumptions that are made on properties of the image. However, if the conventional technique lacks any such prior knowledge, undesired effects arises, such as, background enhancement or loss of contrast. Due to background enhancement, it is difficult to distinguish a noisy background from a shaded region of tissue. Further, due to loss of contrast, for example, in case of bone imaging, correction is used to compensate for low intensity in cortical bone, which is actually a key feature for bone identification.

A conventional technique includes image correction using multichannel blind deconvolution with homomorphic filtering. However, the conventional technique relies on knowledge of image formation process.

Another conventional technique includes spatial intensity correction for radiofrequency (RF) that shades non-uniformities in magnetic resonance imaging (MRI). However, the conventional technique relies on calibration data.

One other conventional technique includes system and method for digital image intensity correction. However, the conventional technique is image-based but does not incorporate priors about target features.

It would be desirable to have an efficient technique to correct intensity inhomogeneities in MR images with very flat contrast.


Figure 1 depicts original zero-echo-time (ZTE) based coronal view of an elbow joint.

Figure 2 depicts coronal view of an elbow joint after intensity homogeneity correction.

Figure 3 depicts tissue mask of the elbow joint.

Figure 4 depicts tissue mask of elbow joint with main object selection and hole filling.

Figure 5 depicts sagittal view of a knee j...