Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · May 2006
Controlled Clinical TrialMultislice multiecho T2* cardiovascular magnetic resonance for detection of the heterogeneous distribution of myocardial iron overload.
To assess the tissue iron concentration of the left ventricle (LV) using a multislice, multiecho T2* MR technique and a segmental analysis. ⋯ Multislice multiecho T2* MRI provides a noninvasive, fast, reproducible means of assessing myocardial iron distribution. The single measurement of mid-septal T2* correlated well with the global T2* value.
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J Magn Reson Imaging · May 2006
Accelerating MR elastography: a multiecho phase-contrast gradient-echo sequence.
To demonstrate the feasibility of using a multiecho phase-contrast (PC) gradient-echo sequence with motion-sensitizing gradient (MSG) to accelerate MR elastography (MRE) acquisitions in comparison to single-echo PC sequences. ⋯ The results demonstrate that a multiecho sequence is suitable for accelerating MRE in nearly homogeneous tissue, such as muscle. It provides equivalent elasticity values in a significantly reduced scan time compared to a single-echo sequence. The maximum achievable ETL factor must be individually determined for the target tissue.
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J Magn Reson Imaging · May 2006
Clinical TrialGradient- and spin-echo T2-weighted imaging for SPIO-enhanced detection and characterization of focal liver lesions.
To evaluate superparamagnetic iron oxide (SPIO)-enhanced breathhold T2-weighted GRASE imaging in detection and characterization of focal liver lesions. ⋯ GRASE is faster and more sensitive to SPIO than FSE, but its sensitivity and specificity were slightly inferior to those of BH-FSE. Image quality is a current limitation.
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J Magn Reson Imaging · Apr 2006
Comparative StudyT1rho relaxation mapping in human osteoarthritis (OA) cartilage: comparison of T1rho with T2.
To quantify the spin-lattice relaxation time in the rotating frame (T1rho) in various clinical grades of human osteoarthritis (OA) cartilage specimens obtained from total knee replacement surgery, and to correlate the T1rho with OA disease progression and compare it with the transverse relaxation time (T2). ⋯ Preliminary results from a limited number of knee specimens (N = 8) suggest that T1rho relaxation mapping is a sensitive noninvasive marker for quantitatively predicting and monitoring the status of macromolecules in early OA. Furthermore, T1rho has a higher dynamic range (>100%) for detecting early pathology compared to T2. This higher dynamic range can be exploited to measure even small macromolecular changes with greater accuracy compared to T2. Because of these advantages, T1rho relaxation mapping may be useful for evaluating early OA therapy.
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J Magn Reson Imaging · Apr 2006
EPI distortion correction from a simultaneously acquired distortion map using TRAIL.
To develop a method for shot-by-shot distortion correction of single-shot echo-planar imaging (EPI) that is capable of correcting each image individually using a distortion measurement performed during acquisition of the image itself. ⋯ Shot-by-shot distortion correction may be performed for EPI images acquired using an extension of the TRAIL technique, ensuring that the correction reflects the actual distortion pattern and not merely a previously measured, but possibly no longer valid, distortion field. This avoids errors due to changes in the distortion field or misregistration of a previously measured distortion map resulting from subject motion.