Measurement and correction of hip cartilage thickness from MR images

For correct diagnosis and treatment of arthropathy, the thickness of articular cartilage has to be measured accurately. Magnetic resonance imaging (MRI) offers a non-radiant and non-invasive method for thickness measurement of articular cartilage. In this paper a novel method has been proposed to measure and correct the articular cartilage thickness of human hip joint from MR images with characteristics of sliced imaging. The cartilage image-plane thickness in the normal direction τ₀ in MR slices was first measured with zero-crossing method in combination with the second directional derivatives of Gaussian blurring, which was validated by mathematical simulation. Based on measurement of τ₀, a correction algorithm was developed to correct the thickness error from overestimation due to oblique slicing, and the corrected thickness τ was obtained. Comparison between the corrected thickness measured with MR images and the thickness measured anatomically of a cadaver hip joint femoral head verifies the effectiveness of the proposed method.