Added value of 3D THRIVE (T1-weighted high-resolution isotropic volume examination) MRI pulse sequence in the detection of bony erosions of sacroiliac joints in patients of spondyloarthritis.

Purpose: Early depiction of bony erosions in sacroiliac (SI) joints increases the diagnostic accuracy of spondyloarthritis. The new 3D magnetic resonance imaging (MRI) sequence THRIVE (T1-weighted high-resolution isotropic volume examination) can depict cartilage erosions in sacroiliac joints. The aim of the study was to compare the diagnostic capacity of the new MRI sequence 3D THRIVE (T1-weighted high-resolution isotropic volume examination) with the routinely used T1 TSE pulse sequence in the depiction of structural erosions in sacroiliac joints by using MRI sequence zero echo time (zero ET) as a reference standard.

Material and methods: Seventy five adult patients were included in this study. They underwent MRI sacroiliac joints examination using routine T1 TSE and STIR pulse sequences with the addition of the new 3D THRIVE and zero echo time (zero ET) sequences. Images of T1 TSE, 3D THRIVE, and zero ET sequences were evaluated by 2 radiolo-gists separately for the detection of sacroiliac joints erosions, then a comparison between T1 TSE and 3D THRIVE sequences was done using a CT-like image MRI sequence zero ET as a reference standard. Sensitivity, specificity, and accuracy for each sequence were calculated by the 2 readers.

Results: Sensitivity, specificity, and accuracy of 3D THRIVE were higher than those of T1 TSE for reader 1 (sensitivity: 94.5% vs. 86.2%; specificity: 93.4% vs. 85.1%; and accuracy 95.2% vs. 88.5%) and for reader 2 (sensitivity: 93.3% vs. 79.9%; specificity: 94.7% vs. 86.2%; and accuracy 95.8% vs. 82.1%).

Conclusions: Using CT-like image MRI sequence zero ET as the reference standard, 3D THRIVE pulse sequencing of the sacroiliac joints has much better diagnostic value in the depiction of bony erosions in patients suspected having spondyloarthritis as compared to the routinely used T1 TSE sequence.