Background <p>Quantitative magnetic resonance T2 mapping is an advanced technique used to evaluate the structural integrity of articular cartilage of joints by measuring T2 relaxation times that reflect water content and collagen fiber organization within the cartilage.</p> Aim <p>This research aimed to investigate the role of T2 mapping in detecting early cartilage degeneration in glenohumeral joint osteoarthritis, which may not be apparent on conventional imaging modalities.</p> Methods <p>In this prospective study, 40 patients with diagnosed or suspected glenohumeral osteoarthritis and 20 healthy controls were enrolled. All participants underwent plain X-ray, conventional magnetic resonance imaging and T2 mapping of the shoulder joint.</p> Results <p>Conventional magnetic resonance imaging identified features of glenohumeral osteoarthritis in 72.7% of examined joints. A statistically significant difference was observed in the mean T2 values of the articular cartilage across the three evaluated joint zones (humeral, central, and glenoid) between patients and controls (<i>p</i> = 0.001), as well as between patients with and without osteoarthritis. T2 cutoff values indicative of cartilage damage were identified as &gt; 34.1&#xa0;ms in the humeral zone, &gt; 32.5&#xa0;ms in the central zone, and &gt; 32.0&#xa0;ms in the glenoid zone, with sensitivities ranging from 84 to 100%. T2 mapping demonstrated superior diagnostic performance with a sensitivity of 97.6%, compared to 71.4% for conventional MRI.</p> Conclusion <p>Quantitative magnetic resonance T2 mapping is sensitive for detecting early biochemical alterations in the cartilage of the glenohumeral joint, potentially identifying degeneration before structural abnormalities become evident on conventional imaging.</p>