Morphological characteristics of sacroiliac joint MRI lesions in axial spondyloarthritis and control subjects

Fatty Acids Composition of the Sacroiliac Joint in Axial Spondyloarthritis: Analysis Using 3.0 T Chemical Shift-Encoded MRI

BACKGROUND

Axial spondyloarthritis (axSpA) is a group of inflammatory diseases that may lead to ankylosis of the sacroiliac joint and spine. Fat lesion in the sacroiliac joint is an important feature in diagnosis and disease progression of axSpA. However, whether there is alteration of fatty acids (FAs) composition has not been investigated using MRI.

PURPOSE

To investigate bone marrow FA composition of the sacroiliac joint in patients with axSpA compared to controls.

STUDY TYPE

Prospective.

SUBJECTS

Eighty five participants (mean age, 32.3 ± 6.1 years): 48 axSpA (25 male, 23 female) and 37 non-SpA controls (18 male, 19 female).

FIELD STRENGTH/SEQUENCE

3.0 T/Two multiple gradient-echo chemical shift-encoded (CSE) MRI which differed only in echo times (TEs) were scanned consecutively.

ASSESSMENT

Axial multi-echo CSE MRI was performed in the sacroiliac joints in vivo. Regions of interest (ROIs) were manually placed on subchondral bone with and without fat lesion in axSpA patients, and on subchondral bone without fat lesion in controls. FA composition was computed within the ROIs using a nonlinear least square method from literature.

STATISTICAL TESTS

Intergroup comparisons were performed using t tests.

RESULTS

In axSpA, male patients had significantly higher monounsaturated FA compared to controls in areas with fat lesion in the sacrum (+12%) and in the ilium (+9%), and in areas without fat lesion in the sacrum (+10%). Significantly lower polyunsaturated FAs were found in areas with fat lesion in the sacrum (-10%) and ilium (-11%), and lower saturated FAs were found in areas without fat lesion in the sacrum (-6%). In female, patients with axSpA had significantly higher saturated FAs in areas with fat lesion in the ilium (+7%) in comparison to controls.

DATA CONCLUSION

FA composition of the sacroiliac joint alters in patients with axSpA, and it can be detected using CSE MRI based analysis.

Differences in topographical location of sacroiliac joint MRI lesions in patients with early axial spondyloarthritis and mechanical back pain

Background

Early diagnostics of axial spondyloarthritis (axSpA) remains a challenge. Traditional imaging one-plane sacroiliac joint (SIJ) MRI assessment is used. By introducing a two-plane assessment system, the objective was to analyse the differences in SIJ MRI changes in early axSpA compared with changes in patients with mechanical back pain (MBP) by exploring the differences in volume and location.

Methods

MRIs in the early diagnostic state of 25 axSpA patients (mean age 31.3 years) and 59 MBP patients (mean age 32.3 years) were included. The MRIs were assessed by two readers regarding the distribution of bone marrow edema (BME) in 14 joint portions and structural changes in six joint portions in addition to SIJ anatomical variations and lumbar spine disc degeneration.

Results

AxSpA patients had a significantly higher overall BME sumscore (volume) of 25.1 compared to MBP patients 6.8, p < 0.005. The MBP group had the highest prevalence (66%) and sumscore (5.7) in the middle anterior sacrum. The axSpA group had significantly higher prevalence and sumscores in all joint portions except the three cartilaginous anterior sacral joint portions, including the ligamentous compartments (prevalence 40–60% compared to 8–15%, p both < 0.005). The axSpA group had also a significantly higher prevalence of erosions and fatty marrow disposition, but there were no differences in the prevalence of anatomical variations except the bipartite iliac bony plate.

Conclusions

AxSpA patients demonstrated a widespread distribution of both inflammatory and structural changes, including high BME occurrence in the ligamentous joint portions whereas patients with MBP had the highest occurrence of BME in the middle anterior sacrum. These findings may help differentiate axSpA patients from other back pain conditions in the early diagnostic phase.

The value of SPARCC sacroiliac MRI scoring in axial psoriatic arthritis and its association with other disease parameters

OBJECTIVES

This study aimed to assess patients with axial psoriatic arthritis (AxPsA) using the Canadian Spondyloarthritis Research Consortium (SPARCC) sacroiliac joint (SIJ) scores and to seek correlations between magnetic resonance imaging (MRI) scores and disease characteristics.

METHODS

Forty PsA patients (32 females, mean age 46.4 years) who had been documented to have active or structural lesions on SIJ MRI were retrospectively evaluated. Disease duration, medications, and disease activity, including Disease Activity in Psoriatic Arthritis (DAPSA), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), minimal disease activity (MDA), and Ankylosing Spondylitis Disease Activity Score (ASDAS) were recorded. On sacroiliac MRI scans, the SPARCC scores of sacroiliac joint inflammation (SIS) and sacroiliac joint structural damage (SSS) were evaluated.

RESULTS

The mean disease duration was 51.4 ± 70.4 months. MRI showed active inflammation in 30 patients (75%) and at least 1 structural lesion in 32 patients (92.5%). The most prevalent structural lesion was erosion (82.5%), followed by fat metaplasia (65%), backfill (12.5%), and ankylosis (2.5%). Only fat metaplasia scores were significantly higher in men than in women (P = .007). Of clinical and laboratory parameters, only C-reactive protein (CRP) was significantly higher in the presence of active inflammation (P = .01). The SIS score was significantly correlated with disease duration (r = -.35) and CRP levels (r = .42,). The SSS score was inversely correlated with BASDAI (r = -.37), ASDAS-CRP (r = -.39), and ASDAS - erythrocyte sedimentation rate (r = -.32). The overall SPARCC scores did not differ between patients in DAPSA remission and non-remission and between those in MDA and non-MDA.

CONCLUSION

Although radiologic involvement is generally not severe in AxPsA, MRI still provides additional information about inflammatory activity and structural lesions. CRP may be helpful in monitoring the radiologic disease activity in AxPsA.

What amount of structural damage defines sacroiliitis: a CT study

OBJECTIVES

To propose a data-driven definition for structural changes of sacroiliac (SI) joints in the context of axial spondyloarthritis (axSpA) imaging on a large collective of CT datasets.

METHODS

546 individuals (102 axSpA, 80 non-axSpA low back pain and 364 controls without back pain) with SI joint CTs were evaluated for erosions, sclerosis and ankylosis using a structured scoring system. Lesion frequencies and spatial distribution were compared between groups. Diagnostic performance (sensitivity (SE), specificity (SP), positive predictive values, negative predictive values and positive and negative likelihood ratios) was calculated for different combinations of imaging findings. Clinical diagnosis served as standard of reference.

RESULTS

Ankylosis and/or erosions of the middle and dorsal joint portions yielded the best diagnostic performance with SE 67.6% and SP 96.3%. Inclusion of ventral erosions and sclerosis resulted in lower diagnostic performance with SE 71.2%/SP 92.5% and SE 70.6%/SP 90.0%, respectively.

CONCLUSIONS

Sclerosis and ventrally located erosions of SI joints have lower specificity on CT of the SI joint in the context of axSpA imaging. Ankylosis and/or erosions of the middle and dorsal joint portions show a strong diagnostic performance and are appropriate markers of a positive SI joint by CT.

Distribution of Acute and Chronic Lesions in the Sacroiliac Joints of Patients with Axial Spondyloarthritis

Objective

In this study, we aimed to investigate whether there was a pattern of distribution of acute and chronic lesions in the sacroiliac joints (SIJ) of patients with axial spondyloarthritis (axSpA).

Methods

A total of 96 patients diagnosed as axSpA were retrospectively included in this study. The Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation score (SIS) and structural score (SSS) were used to evaluate the acute and chronic lesions in the SIJs. Scores representing the distribution of bone marrow edema, fatty lesions and erosions were extracted respectively. By dividing the SIJs into sacral or iliac sections, upper or lower sections, anterior and posterior levels, differences of scores representing acute and chronic lesions were analyzed by Kruskal Wallis’ tests.

Results

SIS scores were not significantly different in sacral or iliac sections, in upper or lower sections, on anterior or posterior levels. SSS scores were also not significantly different in different sections, except for higher occurrence rates of erosions in the iliac sections. Post-hoc analysis showed that there was a higher erosion score in the left ilium than left sacrum, as well as in right ilium than left sacrum.

Conclusion

There was no specific distribution pattern of acute or chronic lesions in the SIJs in patients with axSpA. A bigger study sample was needed to confirm the distribution of erosions in sacral or iliac sections.