Computer-Assisted Quantitative Analysis of Bone Marrow Edema of the Knee: Initial Experience with a New Method

OBJECTIVE: The purpose of this study was to describe a largely observer-independent computer-assisted method for accurate quantitative analysis of bone marrow edema. MATERIALS AND METHODS: Ten patients with bone marrow edema of the knee were included in the study. Coronal STIR images of the affected knees were obtained using a 1.0-T MR scanner. Size and signal intensity of the bone marrow edema were assessed on the basis of gray-scale value analysis and calculation of a threshold value for differentiating normal and edematous bone marrow. All measurements were carried out three times for statistical analysis. RESULTS: The intraobserver coefficient of variation was 0.89% for the volume and 0.94% for the signal intensity of the bone marrow edema, showing the small impact of manual interference on results produced with this method. CONCLUSION: A computer-assisted method for quantification of bone marrow edema has been described. Intraobserver variation was very low, indicating excellent reproducibility of results. Although the method is too time-consuming for clinical use, it is recommended for research purposes.