MR PROTOCOLS FOR IMAGING THE GUINEA-PIG KNEE

Magnetic resonance images of the femorotibial joints of male Dunkin-Ha rtley guinea pigs were obtained in two and three dimensions at 2.35 T using a wide range of T-1 and T-2-weighted imaging sequences. The effe ct of slice position on visualisation of articular cartilage, bone and periarticular tissues in sagittal and coronal sections was investigat ed along with the resolution and signal/noise ratio achievable, Based on that survey, a two-dimensional spin echo sequence (repetition time = 1500 ms, echo time = 40 ms) was found to give optimum visualisation of the normal joint anatomy with in-plane resolution of 75 x 150 mu m and a 1 mm slice thickness in an imaging time of 25 min, This protocol was also found to be highly effective in distinguishing many features of the spontaneous, osteoarthritic-like pathology found in the joints of older animals compared to juveniles and therefore provides a means of monitoring disease progression longitudinally, Three-dimensional s pin echo imaging methods demonstrated focal changes in signal intensit y in the articular cartilage of the medial tibial plateau in older ani mals, The resulting imaging times of several hours, however, precludes their routine use in vivo. (C) 1997 Elsevier Science Inc.