MR T2 Map Technique: How to Assess Changes in Cartilage of Patients with Osteoarthritis of the Knee

Cho, Jae Hwan; Park, Cheol Soo; Lee, Sun Yeob; Kim, Bo Hui

Abstract

By using the MR T2 map technique, this study intends, first, to measure the change of T2 values of cartilage between healthy people and patients with osteoarthritis and, second, to assess the form and the damage of cartilage in the knee-joint, through which this study would consider the utility of the T2 map technique. Thirty healthy people were selected based on their clinical history and current status and another thirty patients with osteoarthritis of the knee who were screened by simple X-ray from November 2007 to December 2008 were selected. Their T2 Spin Echo (SE hereafter) images for the cartilage of the knee joint were collected by using the T2 SE sequence, one of the multi-echo methods (TR: 1,000 ms; TE values: 6.5, 13, 19.5, 26, 32.5. 40, 45.5, 52). Based on these images, the changes in the signal intensity (SI hereafter) for each section of the cartilage of the knee joint were measured, which yielded average values of T2 through the Origin 7.0 Professional (Northampton, MA 01060 USA). With these T2s, the independent samples T-test was performed by SPSS Window version 12.0 to run the quantitative analysis and to test the statistical significance between the healthy group and the patient group. Closely looking at T2 values for each anterior and lateral articular cartilage of the sagittal plane and the coronal plane, in the sagittal plane, the average T2 of the femoral cartilage in the patient group with arthritis of the knee (42.22+/-2.91) was higher than the average T2 of the healthy group (36.26+/-5.01). Also, the average T2 of the tibial cartilage in the patient group (43.83+/-1.43) was higher than the average T2 in the healthy group (36.45+/-3.15). In the case of the coronal plane, the average T2 of the medial femoral cartilage in the patient group (45.65+/-7.10) was higher than the healthy group (36.49+/-8.41) and so did the average T2 of the anterior tibial cartilage (i.e., 44.46+/-3.44 for the patient group vs. 37.61+/-1.97 for the healthy group). As for the lateral femoral cartilage in the coronal plane, the patient group displayed the higher T2 (43.41+/-4.99) than the healthy group did (37.64+/-4.02) and this tendency was similar in the lateral tibial cartilage (i.e., 43.78+/-8.08 for the patient group vs. 36.62+/-7.81 for the healthy group). Along with the morphological MR imaging technique previously used, the T2 map technique seems to help patients with cartilage problems, in particular, those with the arthritis of the knee for early diagnosis by quantitatively analyzing the structural and functional changes of the cartilage.