Cluster Analysis for Identifying Focal Cartilage Defects

A new visualization and cluster analysis tool helps identify focal cartilage T2 and T1rho relaxation time defects in the femoral condyles of an ACL-injured population. Focal defects in cartilage are an important pathological change in Osteoarthritis that has received relatively little attention in the quantitative cartilage MRI literature. We first created projection maps of the 3D cartilage surface within the femoral condyles using a best-fit cylinder to the cartilage-bone interface and radial bins of 1o increments. We then used intensity and area thresholds from cartilage quantitative changes within a healthy population, to identify elevated T2 and T1rho relaxation times over a 1-year follow up period of an ACL-injured population. This proposed tool shows promise for better detecting and tracking early degenerative changes. It may also be used for understanding the cartilage degenerative process and effectively evaluating and monitoring therapeutic approaches for OA. 

Monu UD, Jordan CD, Samuelson BL, Hargreaves BA, Gold GE, McWalter EJ.   Cluster Analysis of Quantitative MRI T2 and T1ρ Relaxation Times of Cartilage Identifies Differences between Healthy and ACL-injured Individuals. Osteoarthritis and Cartilage. 2017 Apr;25(4):513-20.

Online Journal Article

Cluster Maps within ACL-Injured Patients over time

Brian A. Hargreaves
Professor of Radiology (Radiological Sciences Laboratory) and, by courtesy, of Electrical Engineering and of Bioengineering
Garry Gold
Stanford Medicine Professor of Radiology and Biomedical Imaging

Uche Monu, Caroline Jordan, and Emily McWalter are alumni of the BMR group