Optimization of a 3D FLASH Water Excitation MRI Sequence for the Visualization of Articular Cartilage

Objective To optimize a rapid cartilage dedicated 3D-FLASH sequence using water excitation instead of conventional spectral fat suppression and compare the value of 3D-WE-FLASH sequence with 3D-FS-FLASH on evaluating articular hyaline cartilage of knee in 10 healthy volunteers.Methods.The knees of ten volunteers were scanned at 1.5T by using sagittal 3D-WE-FLASH and 3D-FS-FLASH,and different repetition time(TR),echo time(TE),or flip angle(FA) were adoped in 3D-WE-FLASH sequence.The signal noise ratio of cartilage was calculated.Then the contrast noise ratio between cartilage and its surrounding tissues,and contrast noise ratio efficiency between cartilage and fluid were calculated to quantitatively analyze the various sequences.Quantitative results were evaluated with repeated measures ANOVA. Results Group 4 had a significantly higher SNR_ca,CNR_ca-fluid,CNR_ca-bone,CNR_ca-fat,CNR_ca-menisus than in the group 1,2,3.Group 2 had a significantly higher SNR_ca,CNR_ca-fluid,CNR_ca-fat,CNR_ca-bone than group 1,3.Group 4 had a significantly higher CNR_ca-fluid eff than group 1,3,and there is no differert with CNR_ca-fluid eff between group2,4. Conclusion 3D-WE-FLASH sequence which had been optimized is valid for short acquisition time and hyaline cartilage visualization.