Systematic Comparison of MRI and ultrasound scores to Assess Arthropathy in Children and Adolescents with Hemophilia

Objective: To adapt the HEAD-US ultrasound score to assess joint changes in hemophilic arthropathy to children and adolescents and study its reliability and construct validity. To systematically compare ultrasound and MRI techniques to assess joint damage in pediatric hemophilia patients.

Study Design: Single center prospective diagnostic study investigating joint changes in elbow, knee and ankle joints of hemophilic children and adolescents with MRI and ultrasound.

Study Population: Consecutive patients from 4–18 years at the time of investigation with severe or moderate hemophilia, exclusion of patients with musculoskeletal disease other than hemophilia or clinically overt joint bleeding within 28 days prior to investigation requiring treatment.

Imaging Techniques: Ultrasound and MRI are performed in both elbows, knees and ankles. As ultrasound scoring system the HEAD-US Score, including grading of hypertrophic synovia, cartilage damage, bone changes and effusion was compared with MRI scoring, using the IPSG Score of the International Prophylaxis Study Group. All patients underwent blinded MRI investigation within 24 hours of sonographic assessment. For all MRI scores, interreader agreement and correlations with ultrasound scores were analyzed.

Results: We investigated 96 joints in 16 patients with either severe (14) or moderate (2) hemophilia. Age ranged from 6 to 16 (median 11.5 years). The HEAD US activity score ranged from 0–4 (median 0), the MRI IPSG osteochondral damage score ranged from 0 - 5 (median 0, from a scale from 0–8), the MRI IPSG soft tissue damage score ranged from 0 - 6 (median 0, from a scale from 0–9). Agreement between ultrasound and MRI as well as interreader agreement, calculated with intraclass correlation coefficients was good. MRI was more sensitive in detecting minor soft tissue changes whereas the ultrasound scoring rated osteochondral damage higher in part of the joints.

Conclusion: Both ultrasound and MRI provide a congruent assessment of joint damage in children with hemophilia. Our findings suggest that sonographic assessment of arthropathy with the HEAD-US score is able to detect early joint damage in children with hemophilia. Ultrasound imaging is suitable for repeated measurements and outcome assessment in clinical studies.