Three-Dimensional Isotropic Versus Conventional Multisequence 2-Dimensional Magnetic Resonance Imaging of Sacroiliac Joints in Suspected Axial Spondyloarthritis.

OBJECTIVES: The aims of the study were to systematically evaluate the sacroiliac joints of a consecutive series of patients with clinically suspected axial spondyloarthritis and to compare the diagnostic efficacy of 3-dimensional (3D) imaging versus conventional multisequence 2D techniques for sacroiliitis. METHODS: In this cross-sectional multireader validation study, imaging studies of 104 consecutive patients with clinically suspected axial spondyloarthritis obtained with a rheumatology lumbosacral magnetic resonance imaging protocol were evaluated. Three-dimensional coronal oblique reconstructions parallel to the long axis of the sacrum were created. Two blinded readers evaluated 2D and 3D images separately for each study, and findings were compared with the reference standard for the final diagnosis and disease activity. Cohen κ and diagnostic performance measures on 2D and 3D imaging were evaluated and compared. RESULTS: With 2D versus 3D imaging, respectively, the sensitivity for detecting inflammatory cases was 57% versus 62% ( P = 0.1007), the sensitivity for detecting mechanical cases was 89% versus 76% ( P = 0.0312), the sensitivity for detecting active sacroiliitis was 49% versus 64% ( P = 0.0014), and the specificity for detecting active sacroiliitis was 87% versus 76% ( P = 0.0016). Interreader agreement of 2D imaging showed an overall range of κ = 0.27-0.85, and it was best for evaluation of bony ankylosis (κ = 0.85). Interreader agreement of 3D imaging was in an overall range of κ = 0.15-0.64. CONCLUSIONS: Single 3D isotropic magnetic resonance imaging provided adequate assessment of sacroiliac joints in this study and demonstrated significantly higher sensitivity and lower specificity for detecting active sacroiliitis. The initial results indicate that 3D imaging could be used for future works for screening sacroiliitis and abdominopelvic enthesopathy.

Multiparametric Large Field of View Rheumatology Imaging for Axial Spondyloarthropathy Detects Enthesitis in Setting of Inactive Sacroiliac Joint Disease and Impacts Clinical Diagnosis.

AIM: To test the diagnostic efficacy of a multiparametric rheumatology lumbosacral magnetic resonance (MR) imaging protocol in detection and characterization of axial spondylarthritis (SpA) and compare it with serology and clinical findings. METHODS: A consecutive series of multiparametric rheumatology lumbosacral MR imaging examinations performed on 3T MR scanner. Three-dimensional inversion recovery turbo spin echo, precontrast and postcontrast fat-suppressed T1-weighted images, as well as diffusion-weighted images were used to detect active erosions and enthesitis using established criteria. Pearson χ2 was used for categorical variables. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were measured for magnetic resonance imaging (MRI) and serology, based on the final diagnosis from rheumatologists. An alpha error below 0.05 was considered statistically significant. RESULTS: The final study sample included 130 consecutive patients (80 women and 50 men; mean ± SD 44 ± 13 and 45 ± 14 years, respectively). Seventy-eight subjects were diagnosed with axial SpA and 52 with non-SpA arthropathy. In the non-SpA group, 27 patients were diagnosed with osteoarthritis, 6 had unremarkable imaging, whereas 19 were considered as clinically undetermined. There was positive correlation between positive MRI results and SpA diagnosis (P < 0.00001). No correlation existed between positive serology alone and SpA diagnosis (P = 0.0634). Although MRI and serology proved equally sensitive in detecting SpA, the specificity and overall accuracy of MRI were significantly higher. Inflammatory activity was detected in 45 (57.7%) cases, in the pelvic enthesis in 29 (37.2%) cases, in the lumbosacral spine in 16 (20.5%) cases, in the hip joints in 15 (19.2%) cases, and in the pubic symphysis in 5 (6.4%). Inactive sacral disease was seen in 7 of 35 enthesitis patients (20.0%), and in 2 SpA cases, there were no sacral lesions. CONCLUSIONS: The results suggest that in patients with suspected SpA, MRI should not be limited to the sacroiliac joints, but also include enthesitis sites and other joints of the axial skeleton. The multiparametric rheumatology protocol increases the efficacy of MRI in detecting enthesitis and joint inflammatory disease, thereby offering additional information to the clinician and assisting in the early diagnosis/detecting disease activity.