Fat-suppressed fast spin-echo mid-TE (TE[effective]=34) MR images: comparison with fast spin-echo T2-weighted images for the diagnosis of tears and anatomic variants of the glenoid labrum

Objective. To compare the sensitivity, specificity, and accuracy of fat-sup pressed fast spin-echo (FSE) mid-TE (TE[effective]=34) images with fat-supp ressed FSE T2-weighted images for the diagno sis of labral abnormalities, Design and patients. The study included 27 consecutive patients who had axi al fat-suppressed FSE T2-weighted and fat-suppressed FSE mid-TE MR images, and had labral abnormalities diagnosed at arthroscopy. The acquisition time was about 5 min for each sequence, but the mid-TE sequence allowed a highe r spatial resolution than the T2-weighted images (256x256 versus 256x192). Twenty-eight age-matched patients with arthroscopically normal labra were i ncluded as a control group. The labrum was graded on the MR images as norma l or abnormal separately by two musculoskeletal radiologists who were maske d to the history and arthroscopic results. The surgical findings were used as the gold standard for calculating the sensitivity, specificity, and accu racy for interpreting the correct location of a labral abnormality. The sen sitivity, specificity, and accuracy for the two sequences were compared wit h a McNemar test, and significance defined as P<0.05. Results. For observer 1, the sensitivity for labral abnormalities was 0.59 on the T2-weighted images, and 0.78 on the mid-TE images (P=0.12). The spec ificity was 0.54 for the T2-weighted, and 0.64 for the mid-TE images (P=0.5 1). The accuracy was 0.56 for the T2-weighted, and 0.71 for the mid-TE imag es (P=0.08). For observer 2, the sensitivity/specificity/accuracy was 0.67/ 0.93/0.80 for the T2-weighted, and 0.70/0.86/0.78 for the mid-TE images (al l P>0.5). Conclusion. In this small study there is no statistically significant diffe rence for demonstrating labral abnormalities between FSE T2-weighted images , and higher-resolution fat-suppressed FSE mid-TE (TE[effective]=34) images obtained with a similar acquisition time. Although there was a general tre nd toward higher sensitivity and accuracy with the mid-TE sequence, particu larly for one of the two observers, a larger study is needed to determine w hether this is the preferred single axial pulse sequence for conventional M R imaging of the labrum.