MR imaging of the knee: preliminary results with a 3DFT GRASS pulse sequence

3.0-T Evaluation of Knee Cartilage by Using Three-Dimensional IDEAL GRASS Imaging: Comparison with Fast Spin-Echo Imaging

“…Gradient refocused acquisition in steady-state (GRASS) imaging is an alternative three-dimensional MR pulse sequence that can be used for morphologic cartilage imaging ( 26,27 ). The unspoiled gradient-echo sequence can be combined with iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) to produce three-dimensional images of the knee joint with high-signal intensity synovial fl uid and robust fat suppression that is insensitive to magnetic fi eld inhomogeneity ( 28 ).…”

MRI of the knee

“…In general the 3D gradient echo sequence appears to be slightly less accurate in diagnosing anterior cruciate disruption (Tyrrell et al, 1988;Solomon et al, 1989;Heron & Calvert, 1992) but an accuracy of 100% has been reported in one study (Spritzer et al, 1988). In the assessment of the posterior cruciate ligament accuracy rates of 100% have been reported for both spin-echo sequences and 3D gradient-echo sequences (Grover et al, 1990;Heron & Calvert, 1992).…”

“…784 tears. It should now be possible for MRI to achieve an accuracy of well over 95% using arthroscopy as the standard for reference (Jackson et al, 1988;Mink, et al, 1988;Spritzer et al, 1988;Tyrrell et al, 1988;Solomon et al, 1989;Fischer et al, 1991;Araki et al, 1992;Heron & Calvert, 1992). A higher false positive than false negative rate is consistently reported in the assessment of meniscal tears using MRI and there are several possible explanations for discrepant arthroscopic and MRI results.…”

“…Three dimensional gradient-echo images are undoubtedly of value in the knee joint and offer a number of advantages over spin-echo techniques (Haggar et al, 1988;Spritzer et al, 1988;Tyrrell et al, 1988;Reeder et al, 1989;Solomon et al, 1989;Araki et al, 1992;Heron & Calvert, 1992). Using a repetition time (TR) of 0.04 s and an echo time (TE) of 14 ms with a flip angle of 20-40° all the internal structures of the knee may be clearly differentiated and joint effusions are of high signal as on r 2 -weighted images.…”

Magnetic resonance imaging of the shoulder: rationale and current applications

“…We believe this techique warrants further investigation as a means of assessing glenoid labrum abnormalities. Recent articles have appeared detailing the usefulness of three-dimensional Fourrier transform volume acquisition in the knee [35,37]. We believe this technique holds promise for the shoulder as well; however, off-axis centering is not possible with currently available software.…”