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Typical features of both active and structural sacroiliitis in a 16-year-old male with juvenile spondyloarthropathy. Semicoronal (a) STIR and (b) T1-weighted images show typical features of sacroiliitis within the right iliac bone. a Active lesions seen on semicoronal STIR image including bone marrow edema (black arrows), joint inflammation (whitearrows) and capsulitis (arrowhead). b Semicoronal T1-weighted image of the same boy 3 months later, showing structural lesions: fat lesion (white arrows), sclerosis (black dotted arrows), and erosion (large white arrow) (STIR, short tau inversion recovery)
Source publication
MRI is used for early detection of inflammation of sacroiliac joints as it shows active lesions of sacroiliitis long before radiographs show damage to the sacroiliac joints. Early diagnosis of arthritis allows early treatment of inflammation and can help delay disease progression and prevent irreversible damage. Also, early identification of axial...
Similar publications
For a better understanding of the pathophysiology of spondyloarthropathy (SpA), a detailed anatomical description of the sacroiliac joint is required because sacroiliitis is the earliest and most common sign of SpA and an essential feature for the diagnosis of ankylosing spondylitis. Beyond the anatomy, the histopathology of sacroiliac entheses and...
Citations
... Distinctly in children, the ossifying subchondral bone plate shows partial absence of the cortical black line and frequently appears irregular and blurred at the iliac side of the S1 level, mimicking erosions. 38 As with sacroiliitis, the imaging assessment of enthesitis in children can also be challenging due to the pitfalls related to the ongoing development of the immature skeleton. 38 In children, entheseal radiographic findings within the bone occur very late in the disease. ...
... 38 As with sacroiliitis, the imaging assessment of enthesitis in children can also be challenging due to the pitfalls related to the ongoing development of the immature skeleton. 38 In children, entheseal radiographic findings within the bone occur very late in the disease. In particular, enthesophytes are seen less frequently in children than in adults. ...
... Consequently, we can infer that the distribution of intercornual distance in children older than one year was close to that in adults. However, it is challenging to compare adults with children due to the normal developmental changes that the immature skeleton undergoes [20][21][22], as children are not merely small adults. ...
... Paediatric studies on the fusion time of S5 might explain the changes in intercornual distance from one year of age to adulthood [22][23][24]. The sacral vertebral fusion order is from S5 to S4 and finally to S1 [23,24]. ...
... A recent study revealed that in human embryos, the gene expression pattern of some epiphyseal cells before the emergence of secondary ossification centres might determine their commitment to cartilage formation or ossification [25]. Determining the different fusion times of the sacral vertebrae requires a thorough understanding of the sacrum, which is important for understanding regular changes in children and essential for distinguishing physiologic findings from disease signs [22]. ...
Background and objectives
The intercornual distance in the sacral hiatus has yet to be studied precisely in children. This age-stratified, observational study aimed to clarify the changes in sacral hiatus dimensions and to quantify the correlations between the intercornual distance of the sacral hiatus and age, height, weight, and head circumference by using real-time ultrasonography.
Methods
The patients were stratified into three groups: neonates and infants, toddlers, and schoolchildren. In the operating room, the ultrasonic probe was placed at the sacral cornua to obtain a transverse view of the sacral hiatus, and the intercornual distance was measured three times in millimetres.
Results
The study included a total of 156 patients. The mean ± SD (95%CI) of intercornual distance in neonates and infants (<12 months) was 11.58 ± 1.79 (11.11–12.04) mm, 13.29 ± 1.97 (12.71–13.86) mm in toddlers (13–36 months), and 13.36 ± 2.49 (12.64–14.08) mm in schoolchildren (>36 months).
The mean values of neonates and infants were different from those of toddlers and schoolchildren (p < 0.001), but it was similar between toddlers and schoolchildren (p > 0.05, 95 % CI mean difference −1.10 to 0.95).
Intercornual distance was correlated with age, height, weight, and head circumference before one year of age (Spearman's R values > 0.7), but there was no correlation thereafter (Spearman's p value > 0.05).
Conclusion
In the first year after birth, the intercornual distance increases rapidly with body growth; after one year of age, the sacral hiatus dimension changes significantly. Ultrasound is superior for assessing the gradually ossified cartilage components in older children.
... Interpretation of SIJ MRI in children and adolescents can be more challenging compared to adults due to normal physiological changes during skeletal maturation, which can give rise to diagnostic challenges as they can simulate disease. 9 If not recognized as normal findings, these growthrelated changes can lead to false-positive diagnoses of sacroiliitis. 10,11 Frequent pitfalls are growth-related signal changes in both subchondral bone and in the joint space itself, cortical blurring and irregularities, joint facet defects, and vascular structures. ...
... Another possible pitfall is a misinterpretation of vascular channels abutting the superior edge of the joint as capsulitis. 9,11 Vascular channels cross from the sacral to the iliac side and are mostly seen as a thin line at the cranial side of the joint, usually not continuous on one slice, and continuing beyond the margins of the joint capsule when scrolling through the images [ Figure 3(b)]. ...
... Detecting erosion in children can also be challenging due to normal variability. 9,16 During the ossification process, the bony cortex is not fully ossified and may not appear as a black line on T1-weighted MRI, which is even further emphasized by the fact that the underlying bone marrow in children is still mainly red and thus has relatively low T1 signal, resulting in a lower contrast between cortex and bone marrow. Furthermore, the SIJ articular margins often appear blurred or irregular in children, findings that can make it very difficult to detect erosions, or can even mimic erosions [ Figure 4(a)]. ...
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.
... Therefore, early diagnosis and accurate evaluation of sacroiliac arthritis is particularly important. Magnetic resonance imaging (MRI) is the most sensitive magnetic resonance imaging for assessing inflammatory and structural changes in Spa [11][12][13]. By evaluating the MRI features of can suggest the existence of the SPA and classification of subtypes, play a key role in early diagnosis and treatment decision [14]. ...
Objective
To create an automated machine learning model using sacroiliac joint MRI imaging for early sacroiliac arthritis detection, aiming to enhance diagnostic accuracy.
Methods
We conducted a retrospective analysis involving 71 patients with early sacroiliac arthritis and 85 patients with normal sacroiliac joint MRI scans. Transverse T1WI and T2WI sequences were collected and subjected to radiomics analysis by two physicians. Patients were randomly divided into training and test groups at a 7:3 ratio. Initially, we extracted the region of interest on the sacroiliac joint surface using ITK-SNAP 3.6.0 software and extracted radiomic features. We retained features with an Intraclass Correlation Coefficient > 0.80, followed by filtering using max-relevance and min-redundancy (mRMR) and LASSO algorithms to establish an automatic identification model for sacroiliac joint surface injury. Receiver operating characteristic (ROC) curves were plotted, and the area under the ROC curve (AUC) was calculated. Model performance was assessed by accuracy, sensitivity, and specificity.
Results
We evaluated model performance, achieving an AUC of 0.943 for the SVM-T1WI training group, with accuracy, sensitivity, and specificity values of 0.878, 0.836, and 0.943, respectively. The SVM-T1WI test group exhibited an AUC of 0.875, with corresponding accuracy, sensitivity, and specificity values of 0.909, 0.929, and 0.875, respectively. For the SVM-T2WI training group, the AUC was 0.975, with accuracy, sensitivity, and specificity values of 0.933, 0.889, and 0.750. The SVM-T2WI test group produced an AUC of 0.902, with accuracy, sensitivity, and specificity values of 0.864, 0.889, and 0.800. In the SVM-bimodal training group, we achieved an AUC of 0.974, with accuracy, sensitivity, and specificity values of 0.921, 0.889, and 0.971, respectively. The SVM-bimodal test group exhibited an AUC of 0.964, with accuracy, sensitivity, and specificity values of 0.955, 1.000, and 0.875, respectively.
Conclusion
The radiomics-based detection model demonstrates excellent automatic identification performance for early sacroiliitis.
... Pseudowidening of the sacroiliac joints due to erosions and/or subchondral sclerosis was defined as chronic sacroiliitis. These definitions for sacroiliitis on MRI were made in the light of the Assessment of Spondyloarthritis International Society (ASAS) criteria [27] and Outcome Measures in Rheumatology (OMER-ACT) JIA MRI sacroiliac joint (JAMRIS) scoring system [28][29][30]. ...
... Definition of active sacroiliitis in children is not clear (28)(29)(30). Nevertheless, any subchondral bone marrow edema/osteitis subjacent to sacroiliac joints needs to be addressed differently from those involving other metaphyseal equivalent regions in the ilium and sacrum. ...
... Although the ASAS criteria in adults are notably for < 45 years of age, no minimum age limit is given [27]. Nevertheless, subchondral bone marrow edema/osteitis abutting the sacroiliac joints is now deemed to represent active sacroiliitis also in children according to OMER-ACT JAMRIS scoring system [28][29][30]. Sacroiliitis might be considered within the context of conditions overlapping with CNO such as psoriatic arthritis and ERA [32,33], and 23 of our 28 patients with overlapping conditions (82%) had sacroiliitis. ...
To present MRI distribution of active osteitis in a single tertiary referral center cohort of patients with chronic nonbacterial osteomyelitis (CNO).
Two musculoskeletal radiologists retrospectively reviewed MRI examinations of all patients with a final clinical diagnosis of CNO over 15 years. Sites of active osteitis at any time during the course of disease were divided into seven groups: (A) mandible, sternum, clavicles, or scapulas; (B) upper extremities; (C) subchondral sacrum and ilium immediately subjacent to sacroiliac joints (active osteitis denoting “active sacroiliitis” here); (D) pelvis and proximal 1/3 of femurs (excluding group C); (E) bones surrounding knees including distal 2/3 of femurs and 1/2 of proximal tibias and fibulas; (F) distal legs (including distal 1/2 of tibias and fibulas), ankles, or feet; (G) spine (excluding group C). Temporal changes of lesions in response to treatment (or other treatment-related changes such as pamidronate lines) were not within the scope of the study.
Among 97 CNO patients (53 males [55%], 44 females; age at onset, mean ± SD, 8.5 ± 3.2 years; age at diagnosis, 10.3 ± 3.3 years), whole-body (WB) MRI was performed in 92%, mostly following an initial targeted MRI (94%). A total of 557 (346 targeted and 211 WB) MRIs were analyzed. Biopsy was obtained in 39 patients (40%), all consistent with CNO or featuring supporting findings. The most common locations for active osteitis were groups D (78%; 95% CI 69‒85%) and C (72%; 95% CI 62‒80%).
Pelvis and hips were preferentially involved in this cohort of CNO patients along with a marked presence of active sacroiliitis.
When suggestive findings of CNO are identified elsewhere in the body, the next targeted site of MRI should be the pelvis (entirely including sacroiliac joints) and hips, if whole-body MRI is not available or feasible.
• Heavy reliance on MRI for diagnosis of CNO underscores the importance of suggestive distribution patterns.
• Pelvis and hips are the most common (78%) sites of CNO involvement along with active sacroiliitis (72%).
• Pelvis including sacroiliac joints and hips should be targeted on MRI when CNO is suspected.
Sacroiliitis is commonly seen in patients with axial spondyloarthritis, in whom timely diagnosis and treatment are crucial to prevent irreversible structural damage. Imaging has a prominent place in the diagnostic process and several new imaging techniques have been examined for this purpose. We present a summary of updated evidence-based practice recommendations for imaging of sacroiliitis. MRI remains the imaging modality of choice for patients with suspected sacroiliitis, using at least four sequences: coronal oblique T1-weighted and fluid-sensitive sequences, a perpendicular axial oblique sequence, and a sequence for optimal evaluation of the bone-cartilage interface. Both active inflammatory and structural lesions should be described in the report, indicating location and extent. Radiography and CT, especially low-dose CT, are reasonable alternatives when MRI is unavailable, as patients are often young. This is particularly true to evaluate structural lesions, at which CT excels. Dual-energy CT with virtual non-calcium images can be used to depict bone marrow edema. Knowledge of normal imaging features in children (e.g., flaring, blurring, or irregular appearance of the articular surface) is essential for interpreting sacroiliac joint MRI in children because these normal processes can simulate disease. CLINICAL RELEVANCE STATEMENT: Sacroiliitis is a potentially debilitating disease if not diagnosed and treated promptly, before structural damage to the sacroiliac joints occurs. Imaging has a prominent place in the diagnostic process. We present a summary of practice recommendations for imaging of sacroiliitis, including several new imaging techniques. KEY POINTS: • MRI is the modality of choice for suspected inflammatory sacroiliitis, including a joint-line-specific sequence for optimal evaluation of the bone-cartilage interface to improve detection of erosions. • Radiography and CT (especially low-dose CT) are reasonable alternatives when MRI is unavailable. • Knowledge of normal imaging features in children is mandatory for interpretation of MRI of pediatric sacroiliac joints.
Purpose of review:
Juvenile idiopathic arthritis (JIA) diagnosis and classification is currently still based on clinical presentation and general laboratory tests. Some joints such as the temporomandibular joint (TMJ) and sacroiliac (SI) are hard to assess and define as actively inflamed based on clinical examination. This review addresses these difficult to assess joints and provides the latest evidence for diagnosis and treatment.
Recent findings:
Recommendations on clinical examination and radiological examination are available. Recent 2021 ACR recommendations were made for TMJ arthritis and in 2019 for sacroiliitis.
Summary:
New evidence to guide clinical suspicion and need for further investigations are available for these hard to assess joints. These guidelines will help healthcare providers in diagnosis and treatment assessment.
