Journal of magnetic resonance imaging : JMRI
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In 1984, Dixon published a first paper on a simple spectroscopic imaging technique for water and fat separation. The technique acquires two separate images with a modified spin echo pulse sequence. One is a conventional spin echo image with water and fat signals in-phase and the other is acquired with the readout gradient slightly shifted so that the water and fat signals are 180 degrees out-of-phase. ⋯ These applications, as well as the potential that the technique can be made highly insensitive to magnetic field inhomogeneity, have generated substantial research interests and efforts from many investigators. As a result, significant improvement to the original technique has been made in the last 2 decades. The following article reviews the underlying physical principles and describes some major technical aspects in the development of these Dixon techniques.
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J Magn Reson Imaging · Sep 2008
Double-reference cross-correlation algorithm for separation of the arteries and veins from 3D MRA time series.
To present a novel postprocessing technique for artery/vein separation and background suppression from contrast-enhanced time-resolved magnetic resonance angiography datasets in order to improve the diagnosis of vessel pathologies and arteriovenous fistulas. ⋯ This method can be helpful in the diagnosis of vascular diseases in subjects where bolus dispersion makes it difficult to discriminate between arteries and veins with standard methods (subtraction or correlation analysis).
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To compare various Array Spatial and Sensitivity Encoding Technique (ASSET)-enhanced T2W SSFSE (single shot fast spin echo) and T1-weighted (T1W) 3D SPGR (spoiled gradient recalled echo) sequences for polyp detection and image quality at MR colonography (MRC) in a phantom model. Limitations of MRC using standard 3D SPGR T1W imaging include the long breath-hold required to cover the entire colon within one acquisition and the relatively low spatial resolution due to the long acquisition time. Parallel imaging using ASSET-enhanced T2W SSFSE and 3D T1W SPGR imaging results in much shorter imaging times, which allows for increased spatial resolution. ⋯ Parallel imaging using ASSET-enhanced T2W SSFSE and T1W 3D SPGR improves the ability to detect significant colon polyps in an MRC phantom model.
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J Magn Reson Imaging · Sep 2008
Multicenter StudyEvaluation of cardiac biventricular segmentation from multiaxis MRI data: a multicenter study.
To validate a volumetric biventricular segmentation solution for multiaxis cardiac magnetic resonance (CMR) images. ⋯ Fully automatic segmentation produces good results in the assessment of left ventricular volume andendocardial border. Two minutes of user interaction are needed to obtain accurate results for the right ventricle.
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J Magn Reson Imaging · Sep 2008
Comparative StudyFree-breathing, nongated real-time delayed enhancement MRI of myocardial infarcts: a comparison with conventional delayed enhancement.
To compare a free-breathing, nongated, and black-blood real-time delayed enhancement (RT-DE) sequence to the conventional inversion recovery gradient echo (IR-GRE) sequence for delayed enhancement MRI. ⋯ RT-DE can be used for delayed enhancement imaging during free-breathing and without cardiac gating.