Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jun 2007
Black-blood T2* technique for myocardial iron measurement in thalassemia.
To compare the effectiveness and reproducibility of a new black-blood sequence vs. a conventional bright-blood gradient-echo T2* sequence for myocardial iron overload measurement in thalassemia. ⋯ The black-blood T2* technique yields high-contrast myocardial images, provides clearly depicted myocardial borders, and avoids blood signal contamination of the myocardium while yielding improvements in interobserver variability.
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J Magn Reson Imaging · Jun 2007
TSE with average-specific phase encoding ordering for motion detection and artifact suppression.
To detect motion-corrupted measurements in multi-average turbo-spin-echo (TSE) acquisitions and reduce motion artifacts in reconstructed images. ⋯ The proposed method combines a novel data acquisition scheme, a robust motion detection algorithm, and a simple motion correction algorithm. It is effective in reducing motion artifacts for images corrupted by either bulk motion or local motion that occasionally happens during data acquisition.
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J Magn Reson Imaging · Jun 2007
Three-dimensional gradient-echo imaging for percutaneous MR-guided laser therapy of liver metastasis.
To evaluate the use of three-dimensional (3D) gradient-echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR-guided catheter placement for laser therapy of liver metastases. ⋯ 3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis.
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J Magn Reson Imaging · Jun 2007
Quantification of perfusion and permeability in breast tumors with a deconvolution-based analysis of second-bolus T1-DCE data.
To test the feasibility of using a second-bolus injection, added to a routine breast MRI examination, to measure regional perfusion and permeability in human breast tumors. ⋯ In terms of these perfusion values, our method appears promising to quantitatively characterize tumor pathophysiology. However, the number of patients was limited, and the separation between malignant and benign groups was not clear-cut. Additional parameters generated through compartment modeling may improve the tumor differentiation.
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To evaluate the impact of data quality on the localization of brain activation in functional magnetic resonance imaging (fMRI) and to explore whether the temporal contrast-to-noise-ratio (CNR) provides a quantitative parameter to estimate fMRI quality. ⋯ Calculating the CNR using an adaptive low-pass filter gives similar results to a GLM-based approach and could be advantageous for cases in which the hemodynamic response function (HRF) differs significantly from common assumptions. The CNR can be used to identify and exclude runs with suboptimal CNR, and to identify sessions with insufficient data quality. The CNR may serve as a quantitative and intuitive parameter to assess the performance and quality of clinical fMRI investigations, including information on both functional performance (contrast) and data quality (noise caused by the system and physiology).