ePoster #746 - ISHA Annual Scientific Meeting 2016

Validation Of T1rho MRI As A Biomarker In Hips With Cam-Type Femoroacetabular Impingement

Helen Anwander, MD, Ottawa CANADA
Gerd Melkus, PhD, Ottawa CANADA
Kawan Rakhra
Paul Beaule, MD, FRCSC, Ottawa, Ontario CANADA

University of Ottawa/Ottawa Hospital, Ottawa, Ontario, CANADA

FDA Status Not Applicable

Summary: T1rho MRI values correlate with the established WOMAC functional score in cam-FAI.

Abstract:
Purpose: Cam-type femoroacetabular impingement (FAI) is a major cause of hip osteoarthritis. T1? MRI has the potential to detect early cartilage degeneration at the biochemical level due to its sensitivity to proteoglycan content. The aim of this study was to correlate T1? MRI of hip cartilage with the clinical scores WOMAC and HOOS preoperative as well as the change of T1? values with the change of clinical scores two years after hip preserving surgery in patients with cam-type FAI. Follow up T1? MRI was compared to the preoperative baseline. Methods: In 21 symptomatic hips with cam-type FAI T1? MRI was performed on a 1.5T MRI scanner and WOMAC and HOOS were assessed. Cam-type FAI was defined on CT. Eleven patients were treated conservatively. Ten patients underwent a hip preserving surgery with osteochondroplasty and two years postoperative T1? MRI and assessment of the clinical scores were repeated. The femoral and acetabular cartilage were analysed parallel to the acetabular plane as a whole and divided to assess T1? values from six regions: the lateral, intermediate and medial third of the anterosuperior and the posterosuperior zones. Further the T1? ratio of the anterosuperior to the posterosuperior quadrant was calculated, using the latter as an internal control. Results: Significant correlation between the T1? values in the entire hip cartilage and the WOMAC subscore pain (R=-0.45, p=0.041) were found. Correlations reached significance in the lateral and intermediate third of the anterosuperior quadrant. The strongest correlation was found in the lateral third of the anterosuperior zone with the WOMAC subscore pain (R=-0.61, p=0.004). The change of T1? values in the entire hip cartilage and the total WOMAC score two years after surgery correlated significantly (R=-0.73, p=0.042). The correlation was strongest in the lateral third of the anterosuperior quadrant (R=-0.96, p=0.001). HOOS scores reached only significance with T1? values in one zone, the lateral third of the anterosuperior quadrant. T1? values in the lateral third of the anterosuperior quadrant decreased significantly two years after surgery. Discussion: T1? MRI values correlate with the established WOMAC functional score in cam-FAI. This suggests T1? cartilage mapping has the potential to become a validated, entirely non-invasive test for diagnosis and monitoring of early cartilage damage. The decrease of T1? values postoperative indicates the potential of restoring cartilage after hip preserving surgery.