Pregnancy-related sacroiliac joint findings in females with low back pain: a four-year magnetic resonance imaging follow-up study

Reporting Sacroiliac Joint Imaging Performed for Known or Suspected Axial Spondyloarthritis: Assessment of SpondyloArthritis International Society Recommendations

Whereas previous projects attempted to standardize imaging in patients with axial spondyloarthritis (axSpA), few studies have been published about the need for specific details regarding the image acquisition and lesions that may be less familiar to general radiologists. This work reports consensus recommendations developed by the Assessment of SpondyloArthritis International Society (ASAS) that aim to standardize the imaging reports in patients suspected of having or with known axSpA. A task force consisting of radiologists and rheumatologists from ASAS and one patient representative formulated two surveys that were completed by ASAS members. The results of these surveys led to the development of 10 recommendations that were endorsed by 73% (43 of 59) of ASAS members. The recommendations are targeted to the radiologist and include best practices for the inclusion of clinical information, technical details, image quality, and imaging findings in radiology reports. These recommendations also emphasize that imaging findings that indicate differential diagnoses and referral suggestions should be included in the concluding section of the radiology report. With these recommendations, ASAS aims to improve the diagnostic process and care for patients suspected of having or with known axSpA.

The sacroiliac joint across ages - what is normal?

The anatomy of the sacroiliac joint (SIJ) is complex with wide variations inter-individually as well as intra-individually (right versus left) and a frequent occurrence of anatomical variants. Besides, the joints are subject to strain, which may elicit non-inflammatory subchondral changes such as bone marrow edema (BME), sclerosis, and fat deposition simulating inflammatory SIJ changes. Furthermore, normal physiological changes during skeletal maturation can make interpretation of SIJ magnetic resonance imaging in children challenging. Knowledge about the wide range of normal findings is therefore important to avoid misinterpretation of findings as pathological. This review describes the current knowledge about normal SIJ findings across all ages.

Prognostic value of the clinical and imaging arm of the ASAS criteria for progression of structural sacroiliac joint lesions

OBJECTIVE

To investigate the prognostic value of the two arms of the Assessment of SpondyloArthritis international Society (ASAS) criteria regarding the progression of structural lesions in the sacroiliac joints (SIJs).

METHODS

Information on baseline fulfilment of the ASAS criteria and baseline and follow-up magnetic resonance imaging of the SIJ in 603 patients aged 18-40 years referred with low back pain to an outpatient spine were collected. Magnetic resonance imaging positivity was defined as bone marrow oedema (BMO) in two or more consecutive slices or two or more lesions in one slice, as described in the ASAS definition of sacroiliitis.

RESULTS

Of 71 participants fulfilling the ASAS criteria at baseline, 66 (93%) fulfilled the 'imaging arm' and 14 (20%) fulfilled the 'clinical arm'. The 'clinical arm' predicted the progression of erosions with an odds ratio of 55 (compared with not fulfilling the ASAS criteria), while the 'imaging arm' predicted the progression of erosions with an odds ratio of 8. Moreover, in 24% of the patients in the 'imaging arm', all having BMO at the SIJ at baseline, the BMO disappeared without neither erosions nor ankylosis emerging.

CONCLUSION

We found that the 'clinical arm' was a strong predictor for the progression of SIJ erosion, while the 'imaging arm' had a more modest prognostic value for structural progression.

MRI-guided sacroiliac joint injections in children and adults: current practice and future developments

Common etiologies of low back pain include degenerative arthrosis and inflammatory arthropathy of the sacroiliac joints. The diagnostic workup revolves around identifying and confirming the sacroiliac joints as a pain generator. Diagnostic sacroiliac joint injections often serve as functional additions to the diagnostic workup through eliciting a pain response that tests the hypothesis that the sacroiliac joints do or do not contribute to the patient's pain syndrome. Therapeutic sacroiliac joint injections aim to provide medium- to long-term relief of symptoms and reduce inflammatory activity and, ultimately, irreversible structural damage. Ultrasonography, fluoroscopy, computed tomography, and magnetic resonance imaging (MRI) may be used to guide sacroiliac joint injections. The populations that may benefit most from MRI-guided sacroiliac joint procedures include children, adolescents, adults of childbearing age, and patients receiving serial injections due to the ability of interventional MRI to avoid radiation exposure. Most clinical wide-bore MRI systems can be used for MRI-guided sacroiliac joint injections. Turbo spin echo pulse sequences optimized for interventional needle display visualize the needle tip with an error margin of < 1 mm or less. Published success rates of intra-articular sacroiliac joint drug delivery with MRI guidance range between 87 and 100%. The time required for MR-guided sacroiliac joint injections in adults range between 23-35 min and 40 min in children. In this article, we describe techniques for MRI-guided sacroiliac joint injections, share our practice of incorporating interventional MRI in the care of patients with sacroiliac joint mediated pain, discuss the rationales, benefits, and limitations of interventional MRI, and conclude with future developments.

Back pain and assessment of ankylosing spondylitis activity during gestation: symptoms reflecting exacerbation of the disease and pregnancy

Objective: to study the dynamics of back pain severity and the frequency of its individual components, characterizing the inflammatory and mechanical rhythm, on the background of gestation in women with ankylosing spondylitis (AS) and compare them with manifestations of dorsopathy in healthy pregnant women; to determine the information value of BASDAI during pregnancy, i.e. to identify its components with the optimal sensitivity and specificity ratio for assessing AS activity during gestation.

Patients and methods. The main group consisted of 49 pregnant women with AS who met the modified New York criteria of 1984. The average age of patients was 31.7±4.9 years, the average duration of the disease was 134.4±85.8 months. BASDAI for trimesters of pregnancy was: 2.3 [1.2; 4.4], 2.8 [1.4; 4.2] and 2.2 [1.6; 4.0]. The control group included 51 pregnant women with back pain associated with gestation, without rheumatic diseases. The average age was 28.0±4.4 years. The intensity of back pain was assessed on a numerical rating scale. ROC-analysis was performed with calculation of the area under the curve (AUC) of each component of BASDAI in each pregnancy trimester.

Results and discussion. More than 80% of pregnant women with AS experienced back pain, while the intensity of general back pain did not differ from that in the control group. Night back pain with improvement on awakening in the main group was present in 70%, 58% and 68.8% of women, respectively, in the I-III trimesters; its intensity was 3 [1; 5], 3.5 [3; 6] and 3.4 [2; 5] respectively; the frequency and severity of night pain were higher than in the control group. The number of women with improvement after exercise in the II and III trimesters did not differ in both groups. In the second half of pregnancy, 40% of AS patients noted improvement during rest, 52.1% – increased pain after exercise; the frequency of mechanical rhythm pain elements remained lower than in the control group. The AUC value for BASDAI in the first trimester was 0.74; AUC of all BASDAI components was >0.5. In the II and III trimesters, the AUC values for fatigue and back pain were 0.8.

Conclusion. During pregnancy the vast majority of women with AS experience back pain, the nature of which changes in the second half of gestation. Night pain that improves on awakening reflects AS activity and is not related to pregnancy. The BASDAI components of severity and duration of morning stiffness have the highest classification value during pregnancy.

 

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.