Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine
-
This pilot study presents a technique for three-dimensional and quantitative analysis of meniscus shape, position, and signal intensity and compares results in knees with (n = 20) and without (n = 11) radiographic osteoarthritis. 3-T MR images with 2mm section thickness were acquired using a proton density-weighted, fat-suppressed, coronal, fast spin-echo sequence. Segmentation of the tibial, femoral, and external surface of the medial meniscus and the tibial joint surface was performed. ⋯ Key results included a greater size (i.e., volume, surface areas, and thickness), increased medial extrusion (i.e., greater extrusion distance, greater meniscal area uncovered by tibial surface), and elevated signal intensity of the medial meniscus in osteoarthritis than in nonosteoarthritis knees, particularly in the meniscus body. These results need to be confirmed in larger cohorts, preferably under weight-bearing conditions.
-
Conventional T(2)-weighted turbo/fast spin echo imaging is clinically accepted as the most sensitive method to detect brain lesions but generates a high signal intensity of cerebrospinal fluid (CSF), yielding diagnostic ambiguity for lesions close to CSF. Fluid-attenuated inversion recovery can be an alternative, selectively eliminating CSF signals. However, a long time of inversion, which is required for CSF suppression, increases imaging time substantially and thereby limits spatial resolution. ⋯ Dual acquisition in each time of repetition is performed, wherein an in phase between CSF and brain tissues is achieved in the first acquisition, while an opposed phase, which is established by a sequence of a long refocusing pulse train with variable flip angles, a composite flip-down restore pulse train, and a short time of delay, is attained in the second acquisition. A CSF-suppressed image is then reconstructed by weighted averaging the in- and opposed-phase images. Numerical simulations and in vivo experiments are performed, demonstrating that this single pulse sequence may replace both conventional T(2)-weighted imaging and fluid-attenuated inversion recovery.
-
The purpose of this study is (1) to determine the correlation between T(1rho) and T(2) and degenerative grade in intervertebral discs using in vivo 3.0-T MRI, and (2) to determine the association between T(1rho) and T(2) and clinical findings as quantified by the SF-36 Questionnaire and Oswestry Disability Index. Sixteen subjects participated in this study, and each completed SF-36 and Oswestry Disability Index questionnaires. MRI T(1rho) and T(2) mapping was performed to determine T(1rho) (77 discs) and T(2) (44 discs) in the nucleus of the intervertebral disc, and T(2)-weighted images were acquired for Pfirrmann grading of disc degeneration. ⋯ I.) = 0.56; P < 0.05). Although the averaged values of T(1rho) and T(2) were significantly correlated, they presented differences in spatial distribution and dynamic range, thus suggesting different sensitivities to tissue composition. This study suggests that T(1rho) may be sensitive to early degenerative changes (corroborating previous studies) and clinical symptoms in intervertebral disc degeneration.