POS0341 CONSENSUS-DRIVEN DEFINITION FOR UNEQUIVOCAL SACROILIITIS ON RADIOGRAPHS IN JUVENILE SPONDYLOARTHRITIS

Background

Radiographs are not a sensitive or reliable imaging tool for detection of early sacroiliitis in juvenile spondyloarthritis (JSpA). However, radiographs are still commonly performed in some areas due to difficulty in accessing MRI. As such, radiographs were included in the imaging data considered for an axial disease classification criteria development study, but only when there was no suitable MRI available.

Objectives

We aimed to define criteria for unequivocal evidence of sacroiliitis on pelvic radiography in skeletally immature children and adolescents for use in classification criteria.

Methods

Subjects were a cohort of JSpA patients with suspected axial disease. All subjects had symptom onset prior to age 18 years and underwent MRI as part of a diagnostic evaluation for axial disease; a subset of subjects also had a dedicated pelvic radiograph. Using a web-based interface, 6 musculoskeletal imaging experts, blinded to clinical details, reviewed the radiographs and graded them according to the modified New York (mNY) criteria. A two-way random effects intraclass correlation coefficient (ICC) was used to assess agreement. Next, the central imaging team underwent an iterative consensus process to define unequivocal evidence of sacroiliitis on pelvic radiography in skeletally immature children. Radiographs with at least two raters assigning a non-zero mNY grade were re-reviewed for the presence/absence of “unequivocal evidence of sacroiliitis” according to the consensus definition. Agreement was assessed with Fleiss’s kappa statistic with agreement interpreted as poor ≤0.40, fair 0.41-0.59, good 0.60-0.74, and ≥0.75 excellent. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated to assess performance of the novel definition using structural lesion typical of juvenile axial disease on MRI as the reference standard (erosion in ≥3 sacroiliac joint (SIJ) quadrants or at least one of the following lesions in ≥2 SIJ quadrants: sclerosis, fat lesion, backfill, ankylosis).

Results

Radiographs from 120 subjects, 61% male, median age 14.7 years (range 6.7-20.1 years), had an AP dedicated pelvic radiograph available for scoring. The ICC for mNY grade amongst 6 central raters was fair for joints with at least one rater reporting a non-zero grade (0.45, 95% CI: 0.34-0.57). After multiple iterations and discussion, the consensus definition of unequivocal sacroiliitis by radiograph in skeletally immature children and adolescents was deemed “Unequivocal lesion (erosion, sclerosis, or ankylosis [partial or complete]) that must include at least one iliac bone. When sclerosis is present in isolation, if measurable, should extend ≥5mm from the joint surface. The decision may be influenced by the presence of other lesions, which in themselves do not suffice to meet the criterion.” Sixteen radiographs were assessed using the consensus definition. 8 (50%) were rated as unequivocal sacroiliitis and Fleiss’ kappa statistic was good at 0.61 (95% CI: 0.41-0.80). Across raters, the sensitivity, specificity, PPV and NPV of the consensus definition on radiograph using structural lesions typical of sacroiliitis on MRI as the reference standard were 80% (95%CI: 44.4-97.5), 100% (95% CI: 54.1-100), 100% (63.1-100) and 75% (95% CI:34.9-96.8), respectively.

Conclusion

We propose a consensus-derived definition of unequivocal sacroiliitis by radiography in skeletally immature children and adolescents with good expert rater agreement. Additionally, the consensus-definition had moderate to high sensitivity and PPV and high specificity and NPV with typical structural lesions on MRI as the reference standard. This definition has applicability to JSpA axial disease classification criteria when MRI is unavailable.

Figure 1.

Examples of radiographs with unequivocal evidence of sacroiliitis in skeletally immature children as indicated by definite erosions of both iliac bones (A and B) and definite iliac sclerosis (A).

Disclosure of Interests

Pamela F. Weiss Consultant of: Pfizer

Novartis

Biogen

Lilly

(All < $5K in the past fiscal year), Timothy G. Brandon: None declared, Robert G Lambert Paid instructor for: Novartis, Consultant of: CARE Arthritis, Calyx, Image Analysis Group, Novartis, David M. Biko Employee of: Merck (1998 to 2000), Nancy A. Chauvin Employee of: Forest Pharmaceuticals - Research scientist (1996) and Novartis - Pharmaceutical sales representative (1997), Michael L. Francavilla: None declared, Nele Herregods: None declared, Alison M. Hendry: None declared, Walter P Maksymowych Speakers bureau: Abbvie, Eli-Lilly, Janssen, Novartis, Pfizer, UCB Pharma, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, UCB Pharma, Grant/research support from: Abbvie, Novartis, Pfizer

POS0989 DEVELOPMENT OF INTERNATIONAL CONSENSUS ON A STANDARDIZED IMAGE ACQUISITION PROTOCOL FOR DIAGNOSTIC EVALUATION OF THE SACROILIAC JOINTS BY MRI – AN ASAS-SPARTAN COLLABORATION

Background

In 2009, ASAS published a ‘Definition of active sacroiliitis on MRI for classification of axial spondyloarthritis (axSpA)’. This definition relied on two MRI sequences to make this determination – semicoronal T1 and STIR. Since then, this approach has frequently been used for diagnosis, even though that was never the intent of the definition. In 2015, the European Society of Skeletal Radiology (ESSR) published its recommendations for an SIJ MRI image acquisition protocol (IAP) for diagnostic purposes that required 4 MRI sequences but there is still no IAP that has been widely accepted as a minimum standard worldwide. In 2020, an informal survey of 24 academic sites (12 Europe, 12 North America) confirmed that 24/24 sites performed a minimum of 3 MRI sequences for diagnosis (19 performed 4-8 sequences) because the 2-sequence protocol was considered inadequate.

Objectives

To develop the minimum requirements for a standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis.

Methods

All radiologist members of the ASAS and SPARTAN Classification in axSpA (CLASSIC) project, along with one European and one North American rheumatologist with extensive MRI experience in SpA clinical practice and research, were invited to participate in a consensus exercise. A draft IAP was circulated to all participants along with background information and justification for the draft proposal. Feedback on all issues was received by email, tabulated and recirculated. Participants were broadly in favour of the proposal and two months later a teleconference meeting took place and remaining points of contention were resolved. Examples of the proposed IAP performed on new, 10 and 22 years’ old MRI scanners were made available for review in DICOM format. Next the revised draft of the IAP was presented at the ASAS annual meeting to the entire membership on 14 January 2022, and voted on.

Results

A 4-sequence IAP, 3-semicoronal and 1-semiaxial, is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses (Table 1). It must meet the following requirements: Semicoronal sequences should be parallel to the dorsal cortex of the S2 vertebral body, and include: 1) a sequence sensitive for the detection of active inflammation being T2-weighted with suppression of fat signal; 2) a sequence sensitive for the detection of structural damage in bone and bone marrow with T1-weighting; 3) a sequence that is designed to optimally depict the bone-cartilage interface of the articular surface and be sensitive for detection of bone erosion; plus 4) a semiaxial sequence sensitive for inflammation detection. The IAP was approved at the ASAS annual meeting by a vote of the entire membership with 91% in favour.

Table 1.

A standardized SIJ MRI Acquisition Protocol for diagnostic ascertainment of sacroiliitis

OrientationSequenceTarget Lesion(s)Semicoronal Parallel to the dorsal cortex of the S2 vertebral bodyT1-weighted Spin EchoStructural: Fat lesions, erosion, sclerosis, backfill, ankylosis.T2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)T1-weighted with suppressed fat signal (2D or 3D T1FS)Structural: Erosion of the articular surfaceSemiaxial Perpendicular to semicoronalT2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)

Conclusion

A standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis is recommended and should be comprised of a minimum of 4 sequences, in 2-planes, that will optimally visualize inflammation, structural damage, and the bone-cartilage interface.

Disclosure of Interests

Robert Lambert Paid instructor for: Novartis, Consultant of: Calyx, CARE Arthritis, Image Analysis Group, Xenofon Baraliakos Speakers bureau: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Paid instructor for: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Consultant of: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Grant/research support from: Abbvie, MSD, Novartis, Lilly, Stephanie Bernard Consultant of: Elsevier Amirsys, John Carrino Consultant of: Pfizer, Regeneron, Globus, Carestream, Image Analysis Group, Image Biopsy Lab, Torsten Diekhoff Speakers bureau: Novartis, MSD, Canon MS, Consultant of: Eli Lilly, Iris Eshed: None declared, Kay-Geert Hermann Speakers bureau: AbbVie, Pfizer, MSD, Novartis. Co-founder: BerlinFlame GmbH, Nele Herregods: None declared, Jacob L Jaremko: None declared, Lennart Jans: None declared, Anne Grethe Jurik: None declared, John O’Neill: None declared, Monique Reijnierse: None declared, Michael Tuite Consultant of: GE HealthCare, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, Boehringer Ingelheim, Celgene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, UCB

POS0173 DATA-DRIVEN MRI DEFINITIONS FOR ACTIVE AND STRUCTURAL SACROILIAC JOINT LESIONS IN JUVENILE SPONDYLOARTHRITIS TYPICAL OF AXIAL DISEASE

Background

For classification in juvenile spondyloarthritis (JSpA), it is important to develop cut-offs for active and structural lesions typical of axial disease on MRI that are readily and consistently interpreted. Since the maturing sacroiliac joint (SIJ) looks different from the adult SIJ, the criteria developed for positive MRI in adults may not be applicable in JSpA.

Objectives

As part of a study developing classification criteria for axial disease in JSpA, we aimed to determine quantitative SIJ imaging lesion cut-offs for inflammatory and structural lesions typical of axial JSpA using majority imaging expert decision as the reference criterion.

Methods

Subjects were a retrospective cohort of children with SpA who met the provisional Pediatric Rheumatology International Trials Organization criteria for enthesitis/spondylitis-related juvenile idiopathic arthritis or had a rheumatologist JSpA diagnosis. All subjects had symptom onset prior to age 18 years and underwent MRI as part of a diagnostic evaluation for axial disease. To enable SIJ quadrant-based scoring, all MRIs included semi-coronal slices through the cartilaginous part of the joint on fluid sensitive sequences and on T1-weighted sequences for the assessment of inflammation and structural lesions, respectively. MRIs were reviewed by 6 musculoskeletal imaging experts who were blinded to clinical details. MRI evaluation of the SIJ was based on standardized lesion definitions that were decided by consensus of the central imaging team and represented a mix of definitions from ASAS and the Juvenile Arthritis MRI Score Outcome Measures in Rheumatology working group. Using a web-based interface, raters globally assessed the presence or absence of lesions typical of axial SpA and performed SIJ quadrant or joint based scoring. Lesion scores were generated by averaging the scores of all raters. Sensitivity and specificity of lesion cut-offs were calculated using rater majority (≥4/6 raters) on a global assessment of the presence/absence of active or structural lesions typical of axial SpA with high confidence (confidence of ±3 or stronger on confidence scale from -5, “Definitely No”, to +5, “Definitely Yes”) as the reference standard.

Results

Imaging from 243 subjects, 61% male, median age 14.9 years, had sequences available for detailed MRI scoring. Active inflammatory lesion typical of axial disease in JSpA was defined as bone marrow edema (BME) in at least 3 SIJ quadrants (sensitivity 98.6%, specificity 96.5%). For structural lesion typical of axial JSpA, the optimal cut-off was erosion in at least 3 quadrants or at least one of the following lesions in at least 2 SIJ quadrants: sclerosis, fat lesion, backfill, ankylosis (sensitivity 98.6%, specificity 95.5%).

Conclusion

We propose data-driven cut-offs for active inflammatory and structural lesions on MRI typical of axial disease in JSpA that have high specificity and sensitivity using central imaging global assessment as the reference standard.

Table 1.

Performance of cut-offs for inflammatory and structural lesions of axial disease

Cut-offs for number of SIJ quadrants (any location)Sensitivity (95% CI)Specificity (95% CI)Definite active lesionBME score ≥2100 (95.0-100)93.5 (88.7-96.7)BME score ≥398.6 (92.5-100)96.5 (92.5-98.7)BME, same location on ≥3 consecutive slices88.6 (78.7-94.9)98.8 (95.8-99.9)Definite structural lesionErosion ≥295.7 (88-99.1)96.8 (92.7-99)Erosion, same location on ≥2 consecutive slices94.3 (86-98.4)98.1 (94.5-99.6)Erosion ≥391.4 (82.3-96.8)98.7 (95.4-99.8)Sclerosis ≥262.9 (50.5-74.1)98.1 (94.5-99.6)Fat lesion ≥222.9 (13.7-34.4%)98.7 (95.4-99.8%)Backfill ≥220 (11.4-31.3)100 (97.7-100)Ankylosis ≥21.3 (0.2-4.7)100 (94.9-100)ANY of the following in ≥2 SIJ quadrants: erosion, sclerosis, fat lesion, backfill, ankylosis98.6 (92.3-100)93.6 (88.5-96.9)Erosion ≥3 quadrants OR ≥2 quadrants of at least one of the following lesions: sclerosis, fat, backfill, ankylosis98.6 (92.3-100.0)95.5 (91.0-98.2)

Disclosure of Interests

Pamela F. Weiss Consultant of: Pfizer

Novartis

Biogen

Lilly

(All <$5K in the past fiscal year), Timothy G. Brandon: None declared, Amita Aggarwal: None declared, Ruben Burgos-Vargas Speakers bureau: Not in the last three years.

Novartis, Consultant of: Not in the last four years.

BMS, Lilly, Novartis, Robert A. Colbert: None declared, Gerd Horneff Speakers bureau: Pfizer, Novartis, Janssen, Chugai, Abbvie, Grant/research support from: Pfizer, Novartis, MSD, Chugai, Roche, Abbvie, Rik Joos Speakers bureau: Galapagos, Pfizer, AbbVie, Novartis, Amgen, BMS, Lilly, Grant/research support from: Pfizer, AbbVie, Roche, Ronald Laxer Consultant of: Abbvie, Novartis, Sobi, Sanofi, Eli Lilly Canada, Eli Lilly, Kirsten Minden Speakers bureau: Pfizer, Novartis, Consultant of: Pfizer, Novartis, Angelo Ravelli Speakers bureau: Abbvie, Novartis, SOBI, Angelini, Reckitt-Benkiser, Roche, Pfizer, Alexion, Grant/research support from: Novartis, Pfizer, Nicolino Ruperto Speakers bureau: NR has received honoraria for consultancies or speaker bureaus from the following pharmaceutical companies in the past 3 years: 2 Bridge, Amgen, AstraZeneca, Aurinia, Bayer, Brystol Myers and Squibb, Celgene, inMed, Cambridge Healthcare Research, Domain Therapeutic, EMD Serono, Glaxo Smith Kline, Idorsia, Janssen, Eli Lilly, Novartis, Pfizer, Sobi, UCB., Consultant of: NR has received honoraria for consultancies or speaker bureaus from the following pharmaceutical companies in the past 3 years: 2 Bridge, Amgen, AstraZeneca, Aurinia, Bayer, Brystol Myers and Squibb, Celgene, inMed, Cambridge Healthcare Research, Domain Therapeutic, EMD Serono, Glaxo Smith Kline, Idorsia, Janssen, Eli Lilly, Novartis, Pfizer, Sobi, UCB., Grant/research support from: The IRCCS Istituto Giannina Gaslini (IGG), where NR works as full-time public employee has received contributions from the following industries in the last 3 years: Bristol Myers and Squibb, Eli-Lilly, F Hoffmann-La Roche, Novartis, Pfizer, Sobi. This funding has been reinvested for the research activities of the hospital in a fully independent manner, without any commitment with third parties., Judith Smith Consultant of: Consulting panel of pediatric rheumatologists identifying issues in juvenile spondyloarthritis for Novartis. Paid < $5000, Matthew L. Stoll Consultant of: Currently consulting for Novartis, Shirley ML Tse: None declared, Filip van den Bosch Speakers bureau: Abbvie, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, UCB, Paid instructor for: Amgen, Eli Lilly, Consultant of: Abbvie, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, UCB, Robert G Lambert Paid instructor for: Novartis, Consultant of: CARE Arthritis, Calyx, Image Analysis Group, Novartis, David M. Biko Employee of: Merck (1998-2000), Nancy A. Chauvin Employee of: Forest Pharmaceuticals - Research scientist (1996) and Novartis - Pharmaceutical sales representative (1997), Michael L. Francavilla: None declared, Jacob L Jaremko: None declared, Nele Herregods: None declared, Ozgur Kasapcopur Speakers bureau: Pfizer, Abbvie, Novartis and Roche, Mehmet YILDIZ: None declared, Alison M. Hendry: None declared, Walter P Maksymowych Speakers bureau: Abbvie, Eli-Lilly, Janssen, Novartis, Pfizer, UCB Pharma, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, UCB Pharma, Grant/research support from: Abbvie, Novartis, Pfizer

Atlas of MRI findings of sacroiliitis in pediatric sacroiliac joints to accompany the updated preliminary OMERACT pediatric JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system: Part I: Active lesions

Magnetic resonance imaging (MRI) is an increasingly important tool for identifying involvement of the sacroiliac joints (SIJ) in juvenile idiopathic arthritis (JIA). The key feature for diagnosing active sacroiliitis is bone marrow edema (BME), but other features of active arthritis such as joint space inflammation, inflammation in an erosion cavity, capsulitis and enthesitis can be seen as well. Structural changes may also be seen. Systematic MRI assessment of inflammation and structural damage may aid in monitoring the disease course, choice of therapeutics and evaluating treatment response. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the SIJ in the pediatric population, as well as the different MRI features of SIJ inflammation. This atlas demonstrates fundamental MRI disease features of active inflammation in a format that can serve as a reference for assessing SIJ arthritis according to the updated preliminary JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system proposed by the MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT). The atlas is intended to be read in conjunction with its companion Part 2, Structural Lesions.

POS1323 SACROILIAC JOINT MRI ABNORMALITIES IN JUVENILE SPONDYLOARTHRITIS: AN UPDATE OF DEFINITIONS AND SCORING OF THE OMERACT JUVENILE IDIOPATHIC ARTHRITIS MRI SCORE

Background:

Preliminary definitions for SIJ lesions in the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Imaging score has been reported1. Investigators identified the need to revise the JAMRIS-SIJ item definitions.

Objectives:

To update the JAMRIS-SIJ definitions and scoring method.

Methods:

The OMERACT JAMRI working group was convened to discuss the performance of the score in a reliability exercise using 30 patients. Twenty investigators (12 radiologists, 8 rheumatologists) decided which definitions and scoring methods to be revised, retained or added.

Results:

The revised JAMRI-SIJ is in the Table 1.

Table 1.

Revised OMERACT JAMRIS-SIJ.

ComponentDefinitionSegmentation/sliceScore range/sliceBone Marrow Edema (BME)An ill-defined area of high bone marrow signal intensity within the subchondral bone in the ilium or sacrum on fluid sensitive images4 quadrants/SIJ0-8BME IntensityPresence of hyperintensity of the marrow on fluid sensitive images using the signal of the presacral veins or cerebrospinal fluid as reference1 score/SIJ0-2BME DepthContinuing increased signal on fluid sensitive images of depth ≥ 5mm/ ≥ 1cm from the articular surface using the signal of the presacral veins or cerebrospinal fluid as reference1 score/SIJ0-2OsteitisAn ill-defined area of high bone marrow signal intensity within the subchondral bone in the ilium or sacrum on contrast enhanced T1 weighted sequences4 quadrants/SIJ0-8CapsulitisIncreased signal on fluid sensitive or contrast enhanced T1 weighted sequences involving the superior portion of the SIJ capsulesuperior halves/SIJ0-2Joint space fluidHigh signal intensity equivalent to the CSF on fluid sensitive sequences within the joint space of the cartilaginous portion of the SIJhalves/SIJ0-4Joint space enhancementIncreased signal intensity on contrast enhanced T1 weighted sequences within the joint space of the cartilaginous portion of the SIJhalves/SIJ0-4Inflammation in erosion cavityIncreased signal intensity on fluid sensitive or contrast enhanced T1 weighted sequences in an erosion cavity of the cartilaginous portion of the SIJhalves/SIJ0-4EnthesitisIncreased signal intensity in bone marrow and/or adjacent soft tissue on fluid sensitive or contrast enhanced T1 weighted sequences at sites where ligaments and tendons attach to a bone excluding retroarticular enthesitisScore per case0-1Damage DomainSclerosisA substantially wider than normal area of very low bone marrow signal intensity within the subchondral bone in the ilium or sacrum on a non-fat suppressed sequence, preferably a non-fat suppressed T1 weighted sequence. This feature must also be present on all other sequences, as available4 quadrants/SIJ0-8ErosionA focal loss of the low signal of cortical bone at the osteochondral interface and adjacent marrow matrix on T1 weighted images4 quadrants/SIJ0-8Fat metaplasia lesionHomogeneous increased signal intensity within the subchondral bone marrow on T1weighted images4 quadrants/SIJ0-8BackfillA high signal on non-contrast enhanced T1 weighted sequences in a typical location for an erosion, with signal intensity greater than normal bone marrow, clearly demarcated from adjacent bone marrow by an irregular band of low signal reflecting sclerosis at the border of the original erosionhalves/SIJ0-4AnkylosisPresence of signal equivalent to regional bone marrow continuously bridging a portion of the joint space between the iliac and sacral boneshalves/SIJ0-4

Statement of overarching consideration for all definitions: “[…] in comparison to physiological changes normally seen on MRI examinations of age- and sex-matched children, and visible in 2 planes wherever available.”

Conclusion:

Revised JAMRIS-SIJ has been developed. Validation steps are underway.

References:

[1]Otobo TM, et al. Preliminary Definitions for Sacroiliac Joint Pathologies in the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Imaging Score (OMERACT JAMRIS-SIJ). The Journal of rheumatology. 2019;46(9):1192-7.

Acknowledgements:

The authors acknowledge The Hospital for SickKids Research Trainee Competition (RESTRACOMP) and Queen Elizabeth II/Edward Dunlop Foundation Scholarship In Science and Technology (QEII-GSST) at the University of Toronto for funding provided to Dr. Tarimobo M. Otobo. The authors also acknowledge Prof. Dr. Desiree van der Heijde for providing expert commentary.

Disclosure of Interests:

None declared

Common incidental findings on sacroiliac joint MRI in children clinically suspected of juvenile spondyloarthritis

•

What to look for on MRI of the sacroiliac (SI) joint.

•

Incidental findings are common on MRI of the sacroiliac (SI) joint in children.

•

There is more to see than sacroiliitis on MRI of the sacroiliac (SI) joint.

•

Degeneration, inflammation, tumor and normal variants can be seen on MRI of SI joint.

Purpose

To determine the prevalence of incidental findings on sacroiliac (SI) joint MRI in children clinically suspected of Juvenile Spondyloarthritis (JSpA).

Methods

In this retrospective multi-center study of 540 children clinically suspected of JSpA who underwent MRI of SI joints from February 2012 to May 2018, the prevalence of sacroiliitis and other incidental findings was recorded.

Results

In 106/540 (20 %) children MRI features of sacroiliitis were present. In 228 (42 %) patients MRI showed at least one incidental finding other than sacroiliitis. A total of 271 abnormal findings were reported. The most frequent incidental findings were at lumbosacral spine (158 patients, 29 %) and hip (43 patients, 8 %). The most common incidental finding was axial degenerative changes, seen in 94 patients (17 %). Other less frequent pathologies were: simple (bone) cyst in 15 (2,8 %) patients; enthesitis/tendinitis in 16 (3 %) patients; non-specific focal bone marrow edema (BME) away from SI joints in 10 (1,9 %) patients; ovarian cysts in 7 (1,3 %) patients; BME in the course of chronic recurrent multifocal osteomyelitis (CRMO) in 4 (0,7 %) patients; muscle pathology in 4 (0,7%) patients; benign tumors in 3 (0,6 %) patients; (old) fractures in 3 (0,6 %) patients; bony apophyseal avulsion in 2 (0,4 %) patients and malignant tumors in 2 (0,4 %) patients.

Conclusion

Incidental findings are common on MRI of the SI joints in children clinically suspected of JSpA, particularly at the lumbar spine and hips. They are seen even more frequently than sacroiliitis and can be relevant, as some will have clinical significance or require treatment.

Massive pneumomediastinum with subcutaneous emphysema after elective adenotonsillectomy in children: Involvement of the Boyle-Davis mouth gag

Adenotonsillectomy, a very common surgical procedure in otorhinolaryngology, is considered easy and safe surgery. However, clinicians should be aware of some less common but potentially life-threatening complications. This report discusses subcutaneous emphysema with pneumomediastinum following elective adenotonsillar surgery in children. The Boyle-Davis mouth gag seemed to play a part in the pathogenic mechanism of this rare complication in this case. Better insights in the mechanism of this severe complication of adenotonsillectomy may contribute to the prevention of this complication.

MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a 'positive MRI'

OBJECTIVE

To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME).

MATERIALS AND METHODS

A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16-45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated.

RESULTS

BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis.

CONCLUSION

Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is 'positive' or 'not positive' for sacroiliitis associated with spondyloarthritis.

Atypical Suprasellar Neurocytoma in a 31-Month-Old Child: A Case Report

We report a case of a 31-month-old girl with visual impairment. Magnetic resonance imaging showed a large cystic lesion with a mural nodule in the suprasellar region. Biopsy was performed, and histopathological examination demonstrated an atypical extraventricular neurocytoma (EVN). EVN is a rare neuroepithelial tumor with similar histological and biological characteristics in comparison to intraventricular neurocytoma. However, the morphological appearance of EVN can show wide variability with significant overlap of imaging findings compared with other neoplasms. The majority of EVNs are seen supratentorial involving the cerebral hemispheres. An EVN in the sellar or suprasellar region has only been reported twice in adults and to our knowledge never in children.

Diagnositic value of pelvic enthesitis on MRI of the sacroiliac joints in enthesitis related arthritis

BACKGROUND

To determine the prevalence and diagnostic value of pelvic enthesitis on MRI of the sacroiliac (SI) joints in enthesitis related arthritis (ERA).

METHODS

We retrospectively studied 143 patients aged 6-18 years old who underwent MRI of the SI joints for clinically suspected sacroiliitis between 2006-2014. Patients were diagnosed with ERA according to the International League of Associations for Rheumatology (ILAR) criteria. All MRI studies were reassessed for the presence of pelvic enthesitis, which was correlated to the presence of sacroiliitis on MRI and to the final clinical diagnosis. The added value for detection of pelvic enthesitis and fulfilment of criteria for the diagnosis of ERA was studied.

RESULTS

Pelvic enthesitis was seen in 23 of 143 (16 %) patients. The most commonly affected sites were the entheses around the hip (35 % of affected entheses) and the retroarticular interosseous ligaments (32 % of affected entheses). MRI showed pelvic enthesitis in 21 % of patients with ERA and in 13 % of patients without ERA. Pelvic enthesitis was seen on MRI in 7/51 (14 %) patients with clinically evident enthesitis, and 16/92 (17 %) patients without clinically evident enthesitis. In 7 of 11 ERA-negative patients without clinical enthesitis but with pelvic enthesitis on MRI, the ILAR criteria could have been fulfilled, if pelvic enthesitis on MRI was included in the criteria. There is a high correlation between pelvic enthesitis and sacroiliitis, with sacroiliitis present in 17/23 (74 %) patients with pelvic enthesitis.

CONCLUSIONS

Pelvic enthesitis may be present in children with or without clinically evident peripheral enthesitis. There is a high correlation between pelvic enthesitis and sacroiliitis on MRI of the sacroiliac joints in children. As pelvic enthesitis indicates active inflammation, it may play a role in assessment of the inflammatory status. Therefore, it should be carefully sought and noted by radiologists examining MRI of the sacroiliac joints in children.

Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis

OBJECTIVE

The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA).

MATERIALS AND METHODS

A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded.

RESULTS

STIR and T1/Gd sequences had 100% agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5%) patients, 15 (83%) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33%, SP = 85%) and T1/Gd synovial enhancement (SN = 36%, SP = 92%). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55%, SP = 87%, LR + =4 .2; T1/Gd: SN = 55%, SP = 92%, LR + = 6.9).

CONCLUSION

MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis.

Sex steroids in relation to sexual and skeletal maturation in obese male adolescents

BACKGROUND

Childhood obesity is associated with an accelerated skeletal maturation. However, data concerning pubertal development and sex steroid levels in obese adolescents are scarce and contrasting.

OBJECTIVES

To study sex steroids in relation to sexual and skeletal maturation and to serum prostate specific antigen (PSA), as a marker of androgen activity, in obese boys from early to late adolescence.

METHODS

Ninety obese boys (aged 10-19 y) at the start of a residential obesity treatment program and 90 age-matched controls were studied cross-sectionally. Pubertal status was assessed according to the Tanner method. Skeletal age was determined by an x-ray of the left hand. Morning concentrations of total testosterone (TT) and estradiol (E2) were measured by liquid chromatography-tandem mass spectrometry, free T (FT) was measured by equilibrium dialysis, and LH, FSH, SHBG, and PSA were measured by immunoassays.

RESULTS

Genital staging was comparable between the obese and nonobese groups, whereas skeletal bone advancement (mean, 1 y) was present in early and midadolescence in the obese males. Although both median SHBG and TT concentrations were significantly (P < .001) lower in obese subjects during mid and late puberty, median FT, LH, FSH, and PSA levels were comparable to those of controls. In contrast, serum E2 concentrations were significantly (P < .001) higher in the obese group at all pubertal stages.

CONCLUSION

Obese boys have lower circulating SHBG and TT, but similar FT concentrations during mid and late puberty in parallel with a normal pubertal progression and serum PSA levels. Our data indicate that in obese boys, serum FT concentration is a better marker of androgen activity than TT. On the other hand, skeletal maturation and E2 were increased from the beginning of puberty, suggesting a significant contribution of hyperestrogenemia in the advancement of skeletal maturation in obese boys.

Colon transit time and anorectal manometry in children and young adults with spina bifida

PURPOSE

This study evaluates colon transit time (CTT) and anorectal manometry (ARM) in spina bifida (SB) patients in relation to the level of lesion, mobility, constipation, and continence status.

METHODS

SB patients between 6 and 19 years, who are not using antegrade continence enemas and followed at the SB Reference Centre UZ Ghent, were asked to participate. Medical history was retrospectively retrieved from the medical file. Stool habits were prospectively collected using standardized questionnaires. CTT was measured using the 6-day pellet abdominal X-ray method. ARM was performed in non-sedated children with a water-perfused, latex-free catheter.

RESULTS

Forty out of 52 eligible patients consented to perform CTT, of which 19 also performed the ARM. Fifteen (37 %) SB patients were constipated despite treatment. Twenty-six (65 %) were (pseudo) continent. The total CTT was significantly prolonged in SB patients (median CTT 86.4 vs. 36 h controls). The CTT was significantly prolonged in constipated SB patients compared to non-constipated SB patients (122.4 vs. 52.8 h). Spontaneously continent patients had a normal CTT (33.6 h) as well as a significantly higher resting pressure compared to the pseudo-continent and incontinent SB patients (resting pressure 56.5 vs. 32.5 mmHg). An abnormal CTT was associated with a treatment necessity to achieve pseudo-continence (p = 0.006).

CONCLUSION

CTT in SB patients was significantly prolonged, indicating a neurogenic involvement of the bowel and slow transit constipation. SB patients with a normal CTT and a normal ARM spontaneously achieved fecal continence. CTT can help tailor the continence therapy in SB patients.

Anal canal duplication in an 11-year-old-child

Anal canal duplication (ACD) is the least frequent digestive duplication. Symptoms are often absent but tend to increase with age. Recognition is, however, important as almost half of the patients with ACD have concomitant malformations. We present the clinical history of an eleven-year-old girl with ACD followed by a review of symptoms, diagnosis, treatment, and prognosis based on all the reported cases in English literature.

Bone size and bone strength are increased in obese male adolescents

CONTEXT

Controversy exists on the effect of obesity on bone development during puberty.

OBJECTIVE

Our objective was to determine differences in volumetric bone mineral density (vBMD) and bone geometry in male obese adolescents (ObAs) in overlap with changes in bone maturation, muscle mass and force development, and circulating sex steroids and IGF-I. We hypothesized that changes in bone parameters are more evident at the weight-bearing site and that changes in serum estradiol are most prominent.

DESIGN, SETTING, AND PARTICIPANTS

We recruited 51 male ObAs (10-19 years) at the entry of a residential weight-loss program and 51 healthy age-matched and 51 bone-age-matched controls.

MAIN OUTCOME MEASURES

vBMD and geometric bone parameters, as well as muscle and fat area were studied at the forearm and lower leg by peripheral quantitative computed tomography. Muscle force was studied by jumping mechanography.

RESULTS

In addition to an advanced bone maturation, differences in trabecular bone parameters (higher vBMD and larger trabecular area) and cortical bone geometry (larger cortical area and periosteal and endosteal circumference) were observed in ObAs both at the radius and tibia at different pubertal stages. After matching for bone age, all differences at the tibia, but only the difference in trabecular vBMD at the radius, remained significant. Larger muscle area and higher maximal force were found in ObAs compared with controls, as well as higher circulating free estrogen, but similar free testosterone and IGF-I levels.

CONCLUSIONS

ObAs have larger and stronger bones at both the forearm and lower leg. The observed differences in bone parameters can be explained by a combination of advanced bone maturation, higher estrogen exposure, and greater mechanical loading resulting from a higher muscle mass and strength.

Fibromuscular dysplasia of the carotid artery

We describe the ultrasound-Doppler and angio-CT findings of the internal carotid string-of-beads sign in a patient with fibromuscular dysplasia (FMD). FMD is a disease of unknown etiology typically affecting the medium and larger arteries of young and middle-aged women. The most commonly affected arteries are the renal arteries followed by the internal carotid arteries. The lumbar, mesenteric, celiac, hepatic and iliac arteries are less commonly affected. Patients typically present with renovascular hypertension in case of renal artery involvement, Transient ischemic attack or stroke can be one of the presenting symptoms in carotid artery involvement.