Comparison of a Routine Magnetic Resonance Imaging & T2* Mapping of Articular Cartilage in Knee Osteoarthritis

Abstract

Purpose To detect the knee articular cartilage lesions in T2* mapping as compared to a routine standard magnetic resonance imaging (MRI) at 3T. Material and Methods Twenty-five patients, complaining of knee pain and trauma, underwent knee MRI and were imaged with a standard knee MRI protocol (proton-density-weighted Fat Sat sagittal and axial series, T2weighted sagittal and axial series, and T1-weighted coronal series) and Proton density 3D sagittal and axial sequences are added, then images of T2* relaxation time is generated with color-coded mapping representing the relaxation time. The detected lesions were evaluated for lesion width (mm), lesion depth (1/3, 2/3, or 3/3 of cartilage thickness), and T2 values (20–40 ms, 40–60 ms, or 60– 80 ms). Results The study was conducted on 25 patients (13 female & 12 male with a mean of 44.92 ± 11.74 years). 87 lesions were detected both on MRI and T2 maps, while 41 lesions were visible only on T2* maps. The cartilage lesions’ width and depth measurements showed no statistically significant difference on T2 maps as compared to standard knee MRI. Many lesions (45) had moderately (T2 40–60 ms) increased T2 values, while 29 lesions had slightly (T2 20–40 ms) and 13 lesions with remarkably (T2 60– 80 ms) increased T2 relaxation times. Conclusion T2 mapping of articular cartilage is efficient in cartilage evaluation and may reveal early cartilage lesions not visible on standard clinical MRI.