Comparison and reproducibility of fast and conventional spoiled gradient-echo magnetic resonance sequences in the determination of knee cartilage volume

Quantitation of articular cartilage by magnetic resonance imaging and three -dimensional reconstruction has been validated and is likely to be a useful outcome measure in clinical trials of arthritis. The cost of magnetic reso nance imaging is largely dependent on scanning time. The aim of this study was to compare a fast spoiled gradient-echo sequence magnetic resonance ima ging scanning protocol, which takes 5 minutes and 44 seconds, with the stan dard, previously validated spoiled gradient-echo sequence protocol, which t akes 11 minutes and 56 seconds, in the measurement of knee cartilage volume . Cartilage volumes calculated from the standard and fast magnetic resonanc e imaging sequences were similar. The median absolute percentage overestima tion or underestimation of the cartilage volume with the fast sequence for 10 normal subjects was 2.5, 4.1, and 3.256 for patellar, femoral, and tibia l cartilage, respectively for eight subjects with osteoarthritis, the perce ntages were 4.3 and 3.9% for femoral and tibial cartilage, respectively. Th e fast spoiled gradient-echo sequence protocol had very high intra-rater an d inter-rater reproducibility in normal subjects and in those with osteoart hritis. Because the cost of magnetic resonance imaging scanning is largely determined by scan time, the faster scanning protocol means that the cost o f estimates of knee cartilage volume can be significantly reduced, thus inc reasing the feasibility of this methodology.