Assessment of T2 Relaxation Times for Normal Canine Knee Articular Cartilage by T2 Mapping Using 1.5-T Magnetic Resonance Imaging

Abstract

Abstract Objectives This study aims to assess and compare the T2 relaxation times for articular cartilage of normal canine stifle joints in four regions by T2 mapping using a 1.5-T magnetic resonance imaging (MRI). Methods In vivo prospective study: 20 hindlimbs (left and right) from 10 normal healthy beagle dogs (n = 20). The region of interest (ROI) was subdivided into medial and lateral condyles of femoral cartilage (MF and LF, respectively) and medial and lateral condyles of tibial cartilage (MT and LT, respectively). The T2 relaxation times were assessed in regions where the cartilage thickness was greater than 0.5 mm. Results The median maximum cartilage thickness (mm) of the four ROI were 0.7 (range: 0.9–0.6), 0.6 (range: 0.7–0.5), 0.7 (range: 0.9–0.5) and 0.6 (range: 0.8–0.5) at MF, LF, MT and LT, respectively. The errors in the measurement (%) of the four ROI were 64.3 (range: 50.0–75.0), 75.0 (range: 64.3–90.0), 64.3 (range: 20.0–90.0) and 75.0 (range: 56.3–90.0) at MF, LF, MT and LT, respectively. The median T2 relaxation times (ms) for the articular cartilage of the four ROI were 70.2 (range: 57.9–87.9), 57.5 (range: 46.8–66.9), 65.0 (range: 52.0–92.0) and 57.0 (range: 49.0–66.2) at MF, LF, MT and LT, respectively. The inter-observer correlation coefficient (ICC, 2.1) for the T2 relaxation times of MF was 0.644. Clinical Significance This study offers useful information on T2 relaxation times for articular cartilage of the stifle joint using a 1.5-T MRI in normal dogs.