Journal of magnetic resonance imaging : JMRI
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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
In vivo porcine liver radiofrequency ablation with simultaneous MR temperature imaging.
To demonstrate in vivo MR-guided temperature mapping during radiofrequency (RF) ablation of the liver with a commercially available RF generator modified to allow simultaneous RF treatment and MRI. ⋯ The feasibility of performing RF ablation with a modified commercial RF generator simultaneously with MRI was demonstrated. Interference-free MR temperature maps were produced with both variable respiratory motion and mechanical ventilation, and showed the extent of heating as the ablation progressed.
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J Magn Reson Imaging · Apr 2006
Upper cervical cord area in early relapsing-remitting multiple sclerosis: cross-sectional study of factors influencing cord size.
To determine whether the upper cervical cord area (UCCA) is influenced by disease effect in early relapsing-remitting multiple sclerosis (MS), using statistical modeling to account for potential covariates. ⋯ Atrophy of the upper cervical cord is not readily apparent in most patients early in the course of relapsing-remitting MS. In evaluations of disease-related changes in the UCCA in cross-sectional studies, TICV and gender should be considered as potentially confounding covariates.
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J Magn Reson Imaging · Apr 2006
Focal liver lesions: breathhold gradient- and spin-echo T2-weighted imaging for detection and characterization.
To evaluate breathhold gradient- and spin-echo (GRASE) T2-weighted imaging for the detection and characterization of focal liver lesions. ⋯ T2-weighted breathhold GRASE has the potential to provide faster liver imaging.
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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.