Five‐minute knee MRI for simultaneous morphometry and T₂ relaxometry of cartilage and meniscus and for semiquantitative radiological assessment using double‐echo in steady‐state at 3T

Abstract

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1328-1341.

10‐Min 3D Turbo Spin Echo MRI of the Knee in Children: Arthroscopy‐Validated Accuracy for the Diagnosis of Internal Derangement

“…Reported 3D TSE techniques describe a spectrum of balancing between acquisition speed and image quality with attempts to decrease acquisition time through the use of large isotropic and anisotropic voxel sizes, long echo trains, one‐dimensional parallel imaging factors in excess of 2, and partial Fourier undersampling, which may introduce blurring and aliasing artifacts to various degrees. The spectrum of strategies for the acquisition of 3D TSE pulse sequences ranged from acquisition times of 10–11 minutes with (0.5 mm) isovoxel size and short echo trains to acquisition times of 5–6 minutes with large isovoxel size (0.9 mm), anisotropic voxel size (0.5–0.6 mm), echo trains of up to 121, 3‐fold unidirectional parallel imaging acceleration, and partial Fourier undersampling …”

“…In contrast, the two 3D CAIPIRINHA SPACE TSE pulse sequences of our 10‐minute knee protocol reconstructed instantaneously and automatically after the data acquisition ended, as a background task on the MRI workstation, which required less than 10 seconds for each pulse sequence. A 5‐minute gradient echo‐based double‐echo in steady‐state (DESS) sequence is another approach that allows the simultaneous acquisition of high‐quality morphological images and T 2 quantification …”

“…In contrast to 2D MRI, isotropic 3D MRI offers a strategy to increase the efficiency of knee MRI through reformation of many MR image planes from a single parental dataset. While gradient echo‐based 3D pulse sequences can be acquired in 5 minutes, acquisition times of 10 minutes for isotropic 3D TSE datasets have contributed to limited use in clinical practice . The combination of 3D TSE with bidirectional parallel imaging, Controlled Aliasing In Parallel Imaging Results In Higher Acceleration (CAIPIRINHA), and Sampling Perfection with Application optimized Contrast using different flip angle Evolutions (SPACE) now enables 4‐fold acceleration with high signal‐ and contrast‐to‐noise ratios and minimized aliasing artifacts, which provides an opportunity for a comprehensive, pediatric 3D TSE MRI protocol of the knee with a total exam time of 10 minutes.…”

Combined 5‐minute double‐echo in steady‐state with separated echoes and 2‐minute proton‐density‐weighted 2D FSE sequence for comprehensive whole‐joint knee MRI assessment

“…A water‐excitation sagittal 3D‐DESS sequence was added to the end of the routine knee protocol that consisted of a total of five sequences with PD‐weighting, T 1 ‐weighting, and T 2 ‐weighting (scan parameters in Table ). A 20° flip angle was chosen for DESS in order to maximize the tissue SNR for morphological imaging as well as accurate T 2 measurements for cartilage and meniscus . A 3.4 msec spatial‐spectral RF pulse consisting of six spatially selective sublobes was used for selective water‐only excitation while maintaining a low repetition time.…”

Value of MRI in medicine: More than just another test?

“…While typical MSK MRI protocols for joint are up to 30 minutes long, 3D methods with isotropic resolution can cut the exam time to as little as 5 minutes (Fig. ) …”