How accurate is an MRI at diagnosing injured knee ligaments?

MRI offers high sensitivity for detecting ACL, PCL tears Several prospective studies have compared MRI with arthroscopy for diagnosing ACL and PCL tears (TABLE). All enrolled patients had sustained knee trauma and had had a clinical exam that suggested ligamentous injury. MRI and arthroscopy were performed regardless of MRI findings. The surgeons performing arthroscopy were blinded to the MRI results. Although MRI equipment and techniques varied in all the studies, the sensitivity and specificity remained consistently high for detecting ACL injuries. Thin-slice views, special oblique views, and a fast spin-echo technique didn’t improve either the sensitivity or specificity compared with conventional techniques or views, nor did decreasing the time interval from injury to imaging. Prospective studies of PCL injuries also revealed high sensitivity and specificity with MRI.