Measurement of cartilage thickness in the human knee-joint by magnetic resonance imaging using a three-dimensional gradient-echo sequence.

We studied human specimens and compared data on cartilage thickness measurements with magnetic resonance imaging by using an image analysing system with corresponding histological sections in the middle of each sector. The findings are based on 768 measurements in 26 knee joints. Overall, there was very good magnetic resonance/anatomic correlation (r=0.88). The poorest correlation was in the sectors of the femur (r=0.69). The correlation seemed not to be dependent on the grade of osteoarthritic cartilage lesions. Despite good correlation rates, the mean magnetic resonance/anatomic difference (absolute values) was 0.41 mm (standard deviation (SD) 0.34 mm) or 18.08% (SD 18.9%). Imaging techniques need to be improved if the assessment of cartilage thickness by this means is to be of clinical relevance.