Distinguishing erosions from non-inflammatory lesions in hand MRI: A quantitative morphological approach.

OBJECTIVE

To assess differential MRI characteristics of cortical lesions in patients with and without inflammatory arthritis, distinguishing erosions from non-inflammatory lesions.

METHODS

Lesions were classified into those associated with inflammatory arthritis (IA) (n = 177) and without (n = 148). Two radiologists measured lesion diameter and cortical defect width. Linear mixed models were used for continuous outcome variables and generalized estimating equations for binary outcomes and all predictive modeling to estimate odds ratios and predicted probabilities.

RESULTS

This retrospective study included hand MRI exams of 161 patients (83 female, median age (IQR) 54 (39-69)), with 325 cortical lesions. Mean (±standard deviation) cortical defect width (2.74 ± 1.69 mm vs. 1.81 ± 1.20 mm; p < 0.001) and ratio of cortical defect width to lesion diameter (0.61 ± 0.36 vs. 0.37 ± 0.21; p < 0.001) was significantly greater in IA. Blurred delineation (42% vs. 18%; OR = 3.42, p < 0.001), bone marrow edema (BME) (31% vs. 11%; OR = 3.45, p < 0.001) and signal heterogeneity (51% vs. 36%, OR = 1.80, p < 0.001) were significantly more common in IA. Using the ratio and BME to predict IA yielded a cross-validated AUC of 0.721 (95% CI: 0.535-0.788), with a sensitivity of 58% and a specificity of 85% at an optimal threshold.

CONCLUSION

These results suggest that using a quantitative morphological approach can aid differentiation of erosions from non-inflammatory lesions in hand MRI.