Accuracy of cartilage-specific 3-Tesla 3D-DESS magnetic resonance imaging in the diagnosis of chondral lesions: comparison with knee arthroscopy

Kohl S, Meier S, Ahmad SS, Bonel H, et al. · Journal of Orthopaedic Surgery and Research

Sensitivity fell steeply as lesions got milder — 83.3% for grade IV, 74.1% for grade III, 67.9% for grade II and 8.8% for grade I — while specificity stayed between 99.2% and 99.8% throughout. The errors are therefore overwhelmingly misses rather than false alarms: a scan that reports a high-grade lesion is reliable, and a scan that reports nothing at grade I or II says very little.

Population

210 patients with knee pain (1,260 cartilage surfaces) scanned before arthroscopy

Intervention

3-Tesla MRI with 3D-DESS cartilage-specific sequences, graded on the modified Outerbridge scale

Comparator

Arthroscopic grading of the same surfaces

Limitations

Single-center, one scanner and one sequence, in a population already headed for arthroscopy. The 8.8% grade-I sensitivity is a property of this protocol, not of MRI in general.