T 2 mapping of hip articular cartilage in healthy volunteers at 3T: A study of topographic variation

Purpose To perform baseline T 2 mapping of the hips of healthy volunteers, focusing on topographic variation, because no detailed study has involved hips. T 2 mapping is a quantitative magnetic resonance imaging (MRI) technique that evaluates cartilage matrix components. Materials and Methods Hips of 12 healthy adults (six men and six women; mean age = 29.5 ± 4.9 years) were studied with a 3.0‐Tesla MRI system. T 2 measurement in the oblique‐coronal plane used a multi‐spin‐echo (MSE) sequence. Femoral cartilage was divided into 12 radial sections; acetabular cartilage was divided into six radial sections, and each section was divided into two layers representing the superficial and deep halves of the cartilage. T 2 of these sections and layers were measured. Results Femoral cartilage T 2 was the shortest (–20° to 20° and –10° to 10°, superficial and deep layers), with an increase near the magic angle (54.7°). Acetabular cartilage T 2 in both layers was shorter in the periphery than the other parts, especially at 20° to 30°. There were no significant differences in T 2 between right and left hips or between men and women. Conclusion Topographic variation exists in hip cartilage T 2 in young, healthy adults. These findings should be taken into account when T 2 mapping is applied to patients with degenerative cartilage. J. Magn. Reson. Imaging 2007;26:165–171. © 2007 Wiley‐Liss, Inc.