Width of the articular cartilage of the hip: quantification by using fat-suppression spin-echo MR imaging in cadavers.

OBJECTIVE

Use of MR imaging to measure the width of the articular cartilage has not been thoroughly investigated. The value of a selective fat-suppression spin-echo sequence in the quantitative assessment of articular cartilage of the hip was studied in cadavers.

MATERIALS AND METHODS

Sagittal and coronal images were acquired in 10 cadaveric hips (age range at time of death, 62-81 years). On the coronal and sagittal MR images that were closest to the center of the femoral head, marks were placed every 30 degrees, with the midpoint of the femoral head used as a reference. Cartilage thickness was measured in 123 resulting locations. Sixty-three positions included both femoral and acetabular cartilages, and 60 positions included femoral cartilage without an acetabular counterpart. The findings were compared with corresponding anatomic sections.

RESULTS

For the 60 locations containing only femoral cartilage, significant correlation between MR and anatomic sections was found (Pearson correlation coefficient = .34, p = .0089). Of the 63 locations containing both femoral and acetabular cartilages, the two cartilage layers could be differentiated on the MR images in 50 locations. In these 50, the MR and anatomic measurements of the femoral cartilage correlated significant (r = .58, p less than or equal to .0001). Measurements of the acetabular cartilage in these 50 locations yielded no significant correlation (r = .25, p = .08). When the entire cartilage (femoral plus acetabular) was measured in all 63 locations, the correlation between MR and anatomic measurements was .29 (p = .02). The correlation coefficients obtained in this investigation indicate considerable scattering of the data.

CONCLUSION

Our results show that measurements of articular cartilage thickness of the hip on fat-suppression spin-echo MR images are not sufficiently accurate to be of clinical value.