REPEATABILITY OF PATELLAR CARTILAGE THICKNESS PATTERNS IN THE LIVING,USING A FAT-SUPPRESSED MAGNETIC-RESONANCE-IMAGING SEQUENCE WITH SHORTACQUISITION TIME AND 3-DIMENSIONAL DATA-PROCESSING

A fast, reproducible, and noninvasive method is required for quantifyi ng cartilage thickness clinically and for studying the deformation of articular cartilage during and after mechanical lending ill vivo. The objective of the current investigation was to test the repeatability o f regional distribution patterns of patellar cartilage thickness in th e living on the basis of a Fat-suppressed magnetic resonance imaging s equence with a short acquisition time and three-dimensional digital da ta processing. The knees of eight healthy volunteers were transversall y imaged with a fat-suppressed FLASH-3D (fast low angle shot) sequence (acquisition time: 1 minutes and in seconds). In each case, the joint was newly positioned before each of the six replicate measurements wa s taken. The patellar cartilage was reconstructed three-dimensionally, and the distribution of cartilage thickness was determined with a thr ee-dimensional minimal-distance algorithm. Whereas the cartilage volum e ranged from 3,198 to 7,149 mm(3), the mean coefficient of variation for the 6-fold volume measurement was 1.35%, On average, 75.1% (+/-4.1 %) of all test pixels could be attributed to the same cartilage thickn ess interval (0.5 mm) by image analysis, 14.8% (+/-2.4%) deviated by o ne interval: 6.6% (+/-1.5%), by two intervals: and 3.5% (+/-1.8%). by more than two intervals. We conclude that, on the basis of a magnetic resonance imagine sequence with an acquisition time of less than 5 min utes, the quantitative distribution of cartilage thickness can be dete rmined with high precision in vivo.