SHORT ECHO TIME PROJECTION RECONSTRUCTION MR-IMAGING OF CARTILAGE - COMPARISON WITH FAT-SUPPRESSED SPOILED GRASS AND MAGNETIZATION-TRANSFERCONTRAST MR-IMAGING

PURPOSE: To evaluate short echo time (TE) projection reconstruction ma gnetic resonance (MR) imaging in the detection of cartilage lesions. M ATERIALS AND METHODS: Twenty-seven cartilage regions of 10 human patel lar specimens were examined with the following MR sequences: short TE projection reconstruction (repetition time msec/TE msec, 400/0.15), fa t-suppressed three-dimensional spoiled gradient-recalled acquisition i n the steady state (Spoiled GRASS) (50/10, 60 degrees flip angle), and magnetization transfer contrast (MTC) subtraction (400/6). MR finding s were correlated with histopathologic grading of the cartilage. RESUL TS: For detection of cartilage lesions, sensitivity of projection reco nstruction imaging (100%) was significantly greater (P = .03) than tha t of MTC (62%) but not significantly greater (P > .05) than that of Sp oiled GRASS (81%) imaging. Accuracy of projection reconstruction was s ignificantly greater than that of MTC (P .004) and Spoiled GRASS (P = .03) imaging. Unmasking of collagen fibers was most predictive of abno rmal signal intensity of the cartilage with all sequences. CONCLUSION: In vitro, short TE projection reconstruction MR imaging provides supe rior delineation of cartilage lesions when compared with two other seq uences. On Spoiled GRASS and MTC images, signal intensity of the super ficial layer of cartilage is not a reliable sign for surface integrity .