Synthetic T2-weighted images and T2 quantification using GRAPPATINI for shoulder joint evaluation: comparison with...

To evaluate the diagnostic equivalence of GRAPPATINI-derived synthetic fat-saturated (fs-) T2-weighted image (T2WI) compared with conventional fs-T2WI for assessing supraspinatus tendon (SST) and superior labrum, and to investigate the correlation between GRAPPATINI-derived T2 values and glenohumeral joint cartilage degeneration.

This retrospective study included 23 patients (3 men, 20 women; median age, 62 years) who underwent 3.0 T shoulder MRI including both conventional and synthetic fs-T2WIs. Image quality was quantitatively assessed using relative signal-to-noise ratio (rSNR) and contrast-to-noise ratio (rCNR) at fluid, muscle, glenoid cartilage, humeral cartilage, and tendon, and compared using Wilcoxon signed rank test. Four radiologists independently evaluated the detectability of SST and superior labral lesions, and diagnostic equivalence was assessed using an interchangeability analysis. T2 values were measured in two regions of interest in each of the glenoid and humeral head cartilage, and compared between degenerated and non-degenerated cartilage on conventional T2WI using Mann-Whitney U test.

rSNR differed significantly in glenoid cartilage (p = 0.037) and tendon (p = 0.007), whereas rCNR showed no significant differences. For lesion detectability, conventional and synthetic fs-T2WI were interchangeable in evaluating SST and superior labral abnormalities (upper limits of 95% confidence interval for differences in agreement rates ≤ 3.7% for SST and ≤ 2.7% for labrum). T2 values were significantly higher in degenerated cartilage than in non-degenerated cartilage in both the glenoid (p = 0.01) and the humeral head (p = 0.02).

GRAPPATINI-derived synthetic fs-T2WIs were diagnostically equivalent to conventional fs-T2WI for evaluating SST and superior labral lesions. In addition, GRAPPATINI-derived T2 maps enabled supplementary quantitative assessment of cartilage degeneration.