Abstract
Objective
To determine the prevalence of bone marrow oedema (BME) in osteitis condensans ilii (OCI) on MRI of the sacroiliac joint (SIJ). Secondary objectives include comparisons of socio-demographic characteristics, prevalence of other imaging features (MRI, CT scan), and low back pain in patients with OCI with those in a sex- and age-matched control group.
Methods
A total of 34 patients with OCI, including 29 with MRI, were recruited for retrospective analysis. The SIJ MRIs were retrospectively analysed by two readers. A sex- and age-matched control group of patients without SIJ disorders was included. In both groups, the presence of structural bone abnormalities was assessed by CT scan analysis, and socio-demographic data were obtained by telephone questionnaire. A longitudinal analysis was conducted on patients who had undergone multiple imaging examinations.
Results
All patients were female with a mean age of 34 years. BME was observed in 66% (19/29) of OCI patients. BME in OCI was mainly located in the anterior-middle quadrant (43.48%). OCI patients had significantly more than one delivery (P = 0.0094, McNemar test), even if OCI was found in four nulliparous patients (15%). OCI patients experienced significantly more pain (P = 0.0026, McNemar test).
Conclusion
OCI is an entity found in both pregnant and non-pregnant young women. SIJ BME was found in two-thirds of OCI patients. OCI is a significant cause of BME and should be carefully considered by clinicians when dealing with a patient with low back pain in order to avoid misdiagnosing spondyloarthritis in the presence of BME of the SIJ.
Keywords: musculoskeletal diseases, sacroiliac joint, sacroiliitis, MRI, low back pain, oedema
Key Messages.
Osteitis condensans ilii is a diagnosis that affects young women, often with bone oedema detected by MRI.
Interpreting imaging of the sacroiliac joint must be done following medical history and clinical and biological examination.
Introduction
Osteitis condensans ilii (OCI) was first described by Sicard et al. OCI is a radiographic entity defined as a triangular, bilateral and asymmetric bone condensation, predominantly on the iliac side of the sacroiliac joint (SIJ), without ankylosis or erosion [1–3]. Its prevalence is estimated to be between 0.9% and 2.5% of the population [4]. The OCI is typically observed in a population of young women with a median age of 35 who have recently given birth. However, there are exceptions, with cases reported in young nulliparous women and even men [4–6]. Its pathophysiology remains poorly understood. The main hypothesis is that it is caused by a form of mechanical stress, such as pregnancy [7].
OCI is usually asymptomatic. However, the association of OCI with low back or glutaeal pain has already been reported [4, 8]. Damage to the SIJs is one of the causes of low back pain, whether mechanical, inflammatory or infectious. In this context, MRI plays an important role in aetiological diagnosis by highlighting structural lesions or bone marrow oedema (BME) suggestive of these conditions [8]. In 2009, the ASAS (Assessment of SpondyArthritis international Society in 2009) included the presence of oedema of the SIJs in its diagnostic criteria for the early diagnosis of inflammatory sacroiliitis [9, 10]. However, sacroiliac BME is common even in healthy people and might lead to misdiagnosis, with serious consequences for the treatment of patients [11–15].
We therefore hypothesize that BME might be a frequent finding in OCI. The primary objective of this study was to evaluate the prevalence of BME on sacroiliac MRI in a population aged 18–50 years with OCI. Secondary objectives included comparisons of socio-demographic characteristics, prevalence of other imaging features (MRI and CT), and low back pain in patients with OCI with those in a sex- and age-matched control group. Additionally, the evolution of sclerosis and BME in patients with multiple imaging studies was analysed.
Materials and methods
Design and study population
This retrospective, single-centre case–control study received a favourable approval from the Committee for the Protection of Individuals on 31 July 2023 (Sacro iliac (SI) number: 23.02162.000156). All patients were informed about the study by letter before giving their consent.
From January 2010 to December 2023, patients with an imaging diagnosis of OCI on CT and pelvic MRI available in our imaging centre’s PACS (picture archiving and communication system) were selected for inclusion in the OCI group. Patients were identified in the Radiologic System Information (RIS) with the keyword ‘OCI’. For patients with more than one MRI or CT scan of the SIJ, only the first MRI and CT scans were selected for inclusion in the analysis.
The control group included patients with a pelvic CT scan performed between July 2023 and December 2023 and without OCI or any other sacroiliac disorder. These patients were matched to the patients in the OCI group for age and sex on a 1:1 basis.
All CT scans were reviewed by a radiologist experienced in musculoskeletal imaging (with 15 years of experience) (M.F.B.) to confirm the diagnosis of OCI for OCI patients and to confirm the absence of SIJ disorders for the control group.
The inclusion criteria for the OCI group were as follows: (i) patients with a diagnosis of OCI on CT confirmed by an experienced radiologist without any other pathology of the SIJ (degenerative and infectious remodelling and tumour lesions); (ii) aged between 18 and 50 years; (iii) with pelvic MRI available. The exclusion criteria for the OCI group were as follows: (i) a history of spondylarthritis, (ii) a history of pelvic radiotherapy, (iii) incomplete clinical data and MRI data, (iv) patient under guardianship, and (v) language barriers preventing completion of the questionnaire.
The inclusion criteria for the control group were as follows: (i) availability of a CT scan, including the SIJs, with no pathology of the SIJ on CT. The exclusion criteria for the control group were as follows: (i) a history of SpA, (ii) a history of pelvic radiotherapy, (iii) exclusion of the matched case in the OCI group, (iv) patient under guardianship, and (v) language barrier preventing completion of the questionnaire.
Demographic and clinical evaluation
A brochure containing information about the study was sent via post to patients for the OCI and control groups. This documentation included a detailed explanation of the study, along with the data that would be evaluated from their MRI and CT scans. Additionally, a document containing the questions that would be posed during the telephone interview was provided. Following a minimum period of 1 month, and where no objection had been made, the participants were contacted by phone to answer the questionnaire. Throughout the study, participants were given the opportunity to inform the investigators of their refusal to participate by email, telephone or post.
Demographic data recorded by phone included age, living space, BMI, physical activity (according to the WHO) and whether the participant worked in a physical profession (according to the table of occupational diseases n°98 defined by the French social security system), whether they smoked, drank alcohol or used drugs, Charlson comorbidity index [16], gestational status (gestation/parity), foetal macrosomia, obstetric manoeuvre or assisted reproductive technology (ART), hormonal contraception, a history of endometriosis, polycystic ovarian syndrome (PCOS), fracture or surgery of the pelvis or lumbar spine.
Subsequent to this, the clinical data encompassed the following: symptom location (lumbar, buttocks, radicular), side (right, left), characteristics (mechanical/inflammatory pain), duration of pain (greater or less than 3 months) and sensitivity to non-steroidal anti-inflammatory drugs.
Imaging data
MRI and CT acquisition
MRI scans were performed on a 3.0T or 1.5T unit. The acquisition must include at least axial or oblique coronal T1-weighted turbo spin-echo and short tau inversion recovery (STIR) or T2 fat-saturated or T2 Dixon sequences. CT scans must include the entire SIJ. The CT scans were analysed using a bone filter with MPR (multi-planar reconstructions) in the axial, oblique and coronal planes of the SIJs. Because of the retrospective nature of the study, with examinations carried out on different machines (1.5T/3T MRI and several CT scans), there is no single parameter for time echo (TE), time repetition (TR), matrix and slice thicknesses.
Imaging analysis
MRI and CT scans were independently analysed by two readers (S.G. with 3 years of experience and J.P. with 2 years of experience) who were blinded to clinical information. If the two readers were in disagreement, an experienced radiologist (M.F.B.) was asked to adjudicate cases.
The SIJs were divided into six quadrants (Fig. 1). In a coronal plane, the SIJs were divided into an anterior and a posterior part, defined by the straight line through the middle of the superior plateau of S1 and S2. In an axial plane, the SIJs were divided into three levels: superior (up to the line of the first sacral foramen), middle (between the line between the first and second sacral foramen) and inferior (down to the line of the second sacral foramen).
Figure 1.
MPR for sacroiliac analysis with division into anterior and posterior sides. (a) Sagittal CT of the sacral region. The sacroiliac joints are divided into an anterior and a posterior part, defined by the straight line through the middle of the superior plateau of S1 and S2. (b) Coronal CT scan of the anterior part of the sacroiliac joints. In an axial plane, SI were divided into three levels: superior (up to the line of the first sacral foramen), middle (between the line between the first and second sacral foramen) and inferior (down to the line of the second sacral foramen). MPR: multi-planar reconstruction; SI = sacroiliac joint
MRI analysis
The following were analysed on the MRI scans: (i) BME and (ii) fatty metaplasia. BME was defined as an area of high signal in the subchondral bone on the fat-saturated STIR/T2 Dixon sequence. For BME, the maximum depth, measured as the distance perpendicular to the joint space (less than 5 mm, between 5 and 10 mm, more than 10 mm), and main location on SI quadrants were noted. Fatty metaplasia was defined as an increase in signal intensity on the T1-weighted MRI sequence and a decrease in signal intensity on the fat-saturated STIR/T2 sequence.
CT analysis
The following were analysed on the CT scans: (i) location and depth of sclerosis, defined as an increase in subchondral density relative to the adjacent cancellous bone; (ii) geodes, osteophytes and joint space pinching; (iii) degenerative disc disease and posterior inter-articular osteoarthritis at L4–L5 and L5–S1; (iv) scoliosis, transient lumbosacral anomalies and anatomical variants (accessory SIJ and ilio-sacral complex); and (v) pelvic incidence.
Secondly, in the event that the patient had undergone a more recent CT or MRI scan, the evolution of the sclerosis and BME was assessed. In instances where multiple recent examinations had been conducted, the analysis was confined to the most recent one. The evolution of the sclerosis and BME was classified as either appearing/increasing (in excess of 5 mm), stable or regressed/diminished (in excess of 5 mm).
Statistical analysis
All paired data were subjected to analysis using GraphPad software. All unpaired data were analysed using the statistical analysis software EasyMedStat. The quantitative data were presented with mean, S.D., and range if the data follow the normal distribution. If not, they were presented with the median and interquartile range (Q1–Q3). Categorical data were presented as a percentage of the total number of individuals in the group. The distribution of quantitative data between groups was evaluated using the t-test for matched or unmatched data, adapted to the analyses. The distribution differences for qualitative data were assessed using Fisher’s exact test for unpaired data and the McNemar test for matched data. A p-value of less than 0.05 was considered to be statistically significant.
A subgroup analysis was conducted to compare the CT scan and demographic data of patients in the OCI group with a group with BME and a group without BME. A longitudinal subgroup analysis was also conducted to examine the progression of sclerosis and oedema in patients with multiple imaging.
Results
Patients
A total of 186 patients were identified on the RIS with the keyword ‘OCI’ between January 2010 and December 2023. Of these, 89 underwent pelvic MRI, 73 were less than 50 years of age, and 49 were diagnosed with OCI without any other pathology of the SIJ on CT. Six cases were excluded due to incomplete clinical and MRI data (one patient declined to respond to the questionnaire, four patients did not respond to the telephone calls made by the researchers despite calls being made multiple times, and one patient had passed away). Nine cases were excluded due to a history or suspicion of SpA. Finally, 34 cases were included in the study (Fig. 2).
Figure 2.
Flow chart describing the initial and final cohorts of the OCI group. OCI: osteitis condensans ilii
In the control group, from July 2023 to December 2023, 49 patients were matched with patients with OCI. A total of 34 cases were included in the study to ensure a 1:1 matching ratio.
Demographic data
Only women were included, with an average age of 34 years (S.D.: 6.82; min: 21/max: 50).
There was no difference between the groups for demographic data except for history of delivery, which was significantly more frequent in the OCI group (22/34) than in the control group (12/34) (P = 0.009) (Table 1). Pregnancy was more prevalent in patients with OCI (22/34) than in the control group, but not significantly (15/34) (P = 0.07).
Table 1.
Demographic and gynaecological data for patients with osteitis condensans ilii and controls without osteitis condensans ilii
| Variable | OCI | Control | P-value |
|---|---|---|---|
| N = 34 | N = 34 | ||
| Females, n (%) | 34 (100) | 34 (100) | |
| Age (years), mean (S.D.) | 33.97 (6.74) | 34.29 (6.99) | |
| Urban living space, n (%)a | 17 (65.38) | 16 (61.53) | NS |
| BMI (kg/m2), mean (S.D.)a | 28.56 (7.91) | 26.39 (5.12) | NS |
| Charlson Index (>1), n (%)a | 3 (11.53) | 5 (19.23) | NS |
| Regular physical activity, n (%)a,b | 10 (38.46) | 15 (57.69) | NS |
| Working with heavy loads, n (%)a,c | 10 (38.46) | 8 (30.76) | NS |
| Tobacco, n (%)a | 11 (42.3) | 11 (42.3) | NS |
| Toxic (cannabis) use, n (%)a | 2 (7.69) | 2 (7.69) | NS |
| Alcohol misuse, n (%)a,b | 3 (11.53) | 2 (7.69) | NS |
| Previous pelvic fracture or surgery, n (%)a | 1 (3.84) | 0 0 | NS |
| History of fracture or surgery on the thoracic or lumbar spine, n (%)a | 2 (7.69) | 2 (7.69) | NS |
| Pregnancya, n (%) | 22 (84.61) | 15 (57.69) | NS |
| Pregnancy, median (IQR)a | 2 (2–3) | 2 (1–3) | NS |
| Delivery, n (%)a | 22 (84.61) | 12 (46.15) | 0.0094 |
| Delivery, median (IQR)a | 2 (1.5–2) | 2 (1–2) | NS |
| Obstetrical manoeuvre, n (%)d | 4 (36.36) | 5 (45.45) | NS |
| Macrosomia, n (%)e | 1 (10) | 1 (10) | NS |
| Hormonal contraception, n (%)a | 15 (57.69) | 11 (42.31) | NS |
| Microprogestogenic pill | 5 (19.23) | 4 (15.38) | NS |
| Oestrogen-progestin pill | 4 (15.38) | 2 (7.69) | NS |
| IUD | 5 (19.23) | 3 (11.53) | NS |
| Implant | 1 (3.84) | 2 (7.69) | NS |
| History of endometriosis, n (%)f | 6 (24) | 4 (16) | NS |
| PCOS history, n (%)f | 3 (12) | 2 (8) | NS |
| ART history, n (%)g | 2 (16.6) | 0 (0) | NS |
P-values <0.05 are shown in bold. OCI: osteitis condensans ilii; NS: not significant; IQR: interquartile range; IUD: intra-uterine device; PCOS: polycystic ovarian syndrome; ART: assisted reproductive technology.
Missing data: analyses were carried out only for complete matched pairs, i.e. where data were available for both case and control. n (case) = 26 and n (control) = 26.
Alcohol misuse and regular physical activity as defined by the WHO.
As defined in the tables of occupational diseases (No. 98).
Missing data: n (case) = 11 and n (control) = 11.
Missing data: n (case) = 10 and n (control) = 10.
Missing data: n (case) = 25 and n (control) = 25.
Missing data: n (case) = 12 and n (control) = 12.
MRI findings
BME of the SIJ was found in 65.5% (19/29) of patients with OCI. The characteristics of the BME, including its size, location, and depth, are presented in Table 2. BME was always located on the anterior quadrants of the SIJ and on the antero-median part in 43% of cases and was greater than 10 mm in 61% of cases (Fig. 3).
Table 2.
MRI data in the OCI group
| Variable | OCIN = 29 |
|---|---|
| BME, n (%) | 19 (65.5) |
| Depth (in mm), median (IQR) | 11.5 (8.25–17) |
| Depth, n (%)a | |
| <5 mm | 2 (4.35) |
| Between 5 and 10 mm | 16 (34.78) |
| >10 mm | 28 (60.87) |
| Predominant slope, n (%)b | |
| Right iliac | 2 (10.53) |
| Right sacral | 4 (21) |
| Left iliac | 8 (42.11) |
| Left sacral | 5 (26.32) |
| Predominant quadrant, n (%)a | |
| Anterio-superior | 11 (23.91) |
| Anterio-medial | 20 (43.48) |
| Anterio-inferior | 15 (32.61) |
| Posterio-superior | 0 0 |
| Posterio-medial | 0 0 |
| Posterio-inferior | 0 0 |
| Fatty metaplasia, n (%)c | 4 (3.44) |
Analysis was carried out on the 29 patients in the OCI group on MRI. OCI: osteitis condensans ilii; BME: bone marrow oedema; IQR: interquartile range.
All measurements taken on all slopes combined (right and left iliac and right and left sacral): total number of measurements = 46.
Predominant slopes for each patient with BME (19 patients).
For all 29 patients on all slopes (right and left iliac and right and left sacral): 116 analyses.
Figure 3.
Intramedullary bone oedema on MRI in patient with OCI. Two patients with OCI, STIR sequence in a coronal plane. BME present at the periphery of the sclerosis (arrow head) in the sacral side (a) and in the iliac side (b). OCI: osteitis condensans ilii; STIR: short tau inversion recovery
CT findings
The description of sclerosis, including its side, location, and depth, is presented in Supplementary Table S1, available at Rheumatology Advances in Practice online. Sclerosis was located in the anterior median part of the SIJ in 64% of cases and was greater than 10 mm in 57% of cases.
Osteophytes and geodes were, respectively, more frequent in the OCI group (21.32% and 24.26%) than in the control group (10.29% and 15.44%) (P = 0.02 and P = 0.04).
There were no significant differences between the two groups for the diagnosis of degenerative disc disease and posterior inter-articular osteoarthritis L4–L5 and L5–S1, for the diagnosis of scoliosis, for the diagnosis of anatomical variants (all types combined or each variant studied individually) or for the pelvic incidence value.
Clinical data
92% (24/26) of patients in the OCI group reported experiencing pain (all regions combined), including low back pain 84% (22/26), hip pain 38% (10/26), and radicular pain 61% (16/26), whereas only 50% (13/26) of patients in the control group reported experiencing pain (all regions combined), including low back pain 42% (11/26), hip pain 15% (4/26), and radicular pain 23% (6/26) (P = 0.003) (Supplementary Table S2, available at Rheumatology Advances in Practice online). There were no significant differences between the two groups for the characteristic of pain (mechanical or inflammatory), the duration of pain (greater or less than 3 months) or the sensitivity of pain to non-steroidal anti-inflammatory drugs.
The BME group compared with the non-BME group
The depth of sclerosis was greater in patients with BME (12 mm) than in patients without BME (10 mm) (P = 0.043). No statistically significant differences were observed in demographic or clinical data (Supplementary Tables S3–S5, available at Rheumatology Advances in Practice online).
BME was associated with pain in 54.55% of cases, even if it was not statistically significant (P = 0.3).
Longitudinal analysis
A total of 14 patients had undergone a new scan since the scan that formed the basis of the study. The median time interval between the two scans was 77.94 months. The depth of sclerosis was observed to be lower on the more recent scans (6.5 mm) compared with the older scans (10 mm), which were also included in the main analysis (P = 0.027) (Supplementary Tables S6, available at Rheumatology Advances in Practice online). Figure 4 illustrates the case of a patient from our cohort who underwent two CT scans 12 years, or 142 months, apart, demonstrating regression of the subchondral sclerosis (Fig. 4).
Figure 4.
Evolution of OCI over time. This 36-year-old uniparous patient presented with a reversal of sclerosis as seen on these two scans taken 12 years apart and reported low back pain, with glutaeal or radiculalgia, lasting more than 3 months. On the MRI performed in August 2011, there was left sacral subchondral oedema. (a) We have another MRI, including SI, performed in February 2014, showing a regression of left sacral subchondral oedema. (b) Coronal oblique MPR reconstruction scan with bilateral subchondral sclerosis, without erosion or pinching of the joint space, performed in March 2012. (c) CT scan of oblique coronal MPR reconstruction with diminution of bilateral subchondral sclerosis, without erosion or pinching of the joint space, performed in January 2024. (d) OCI: osteitis condensans ilii; SI = sacroiliac joint; MPR: multi-planar reconstruction
Seven patients had undergone a new MRI scan subsequent to the MRI scan on which the study was based. The median time interval between the two MRI scans was 31.31 months. No difference between the two BME measurements was observed.
Discussion
The primary objective of this study was to evaluate the prevalence of BME in OCI. Our findings suggest that BME is frequent in OCI, as we find BME in 65.5% of patients with OCI. The present study revealed a higher prevalence (65.5% vs. 48%) and depth (greater than 5 mm in 94% vs. 92%) of BME in an OCI population than previously described in the study by Ma et al. [13]. In agreement with the latter study, BME was most commonly located on the anterior side of the joint, and there was no association between the presence of BME and painful symptoms in patients with OCI.
The median depth of sclerosis was found to be greater in patients with BME (12 mm vs. 10 mm, P = 0.043) and less on more recent scans (6.5 mm vs. 10 mm). This would indicate that there is an initial active phase with oedema when sclerosis sets in, followed by a second phase when the sclerosis stabilizes or diminishes, without systematic regression of the associated oedema. This hypothesis was also proposed in the study by Ma et al., suggesting a potential resolution of the sclerosis over time with long-term follow-up (8–20 years by X-ray) [13].
Regarding the socio-demographic data, all patients included in the study were women. The number of patients who had already given birth at least once was significantly higher in the OCI group than in the control group (85% vs. 46%, P = 0.009). In the OCI group, 4/29 (15%) patients were nulliparous. No other socio-demographic factors were associated with OCI. The physiopathology of OCI remains poorly understood, and the biomechanical theory of pregnancy is not applicable in nulliparous patients. The postpartum period has been the subject of some recent research, which showed that BME of the SIJ is frequently observed [6, 17, 18]. These observations indicate that there is a period of stress on the SIJ, although the link between the BME and the development of sclerosis has not been formally demonstrated. Mechanical stress may be observed in circumstances other than pregnancy, such as repetitive microtrauma, which may result in sclerosis due to increased bone vascularization [18]. The hypothesis of a cause-and-effect relationship with pregnancy is also challenged by studies reporting sclerosis emerging after the second birth [19]. To better understand the natural history of OCI, prospective studies should be conducted to analyse the radiographic and MRI changes. The extent and evolution of these features may be subject to significant inter-individual variability.
Regarding the hormonal role in the development of OCI, which was proposed in the study by Parperis et al. [20], our study did not find any significant difference in the use of ART, the use of hormonal contraception, or a history of endometriosis or PCOS between the OCI group and the control group.
The literature often describes OCI as asymptomatic. When it is present, the pain is generally bilateral lumbar pain with radiation to the buttocks or posterior thighs. This is why a diagnosis of spondyloarthritis is often made, potentially leading to misdiagnosis [20–22]. Furthermore, the definition of sacroiliac arthritis on MRI is not sufficiently specific [11–15]. Consequently, imaging should always be carried out after and in the light of an anamnesis and a rigorous clinical and biological examination. The results of our study showed a significant difference between the OCI group and the control group for the criterion ‘pain at all sites combined’, with 92% of patients in the OCI group experiencing pain. A similar result was found in the study by Rodríguez-Pla et al., with 93% of patients in the OCI group and 68% in the control group reporting low back pain [23]. However, no association between the presence of BME and pain was observed in the OCI group.
The strengths of this study are the case–control design allowing comparison of demographic and clinical data, the strict inclusion and exclusion criteria and the blinded radiographic assessment by two independent readers. The limitations of the study are as follows. Firstly, the control group did not benefit from the MRI study; a control group with MRI was not feasible in the retrospective design. Therefore, the control group was used to explore demographic and clinical characteristics rather than imaging findings. Secondly, the cases were selected retrospectively, without adequate physical examination, and with a delay of sometimes several years between the imaging and the completion of the questionnaire. This may have a particular impact on the accuracy of self-reported symptom duration and clinical history. This could influence the associations between clinical factors and imaging findings. Thirdly, the study was conducted retrospectively and at a single centre, with a limited number of participants, and in the absence of previous data, making it difficult to calculate the required sample size. Some subgroup analyses correspond only to preliminary analyses due to the small number of participants. Finally, the OCI group consists of patients presenting with radiological OCI (diagnosed through scannographic definition), precluding the possibility of non-radiological pre-dose analysis of this entity. Consequently, further investigation is required in studies with a larger number of patients and a prospective design to confirm our results and gain a better understanding of the factors that promote OCI and the mechanisms by which it develops.
In summary, BME was present in two-thirds (65.5%) of patients with OCI, with no obvious link between the presence of BME and pain symptoms. OCI is a radiological entity found in young women both in and outside of a post-partum context, with 15% of the women in our study being nulliparous. The OCI is a diagnosis that should be considered when interpreting imaging of the SI, following a thorough history and clinical and biological examination, in the context of low back pain and buttock pain, even in the presence of BME, in order to avoid an erroneous diagnosis of spondyloarthritis. However, it should not be forgotten that OCI could be a differential diagnosis of low back pain, particularly due to the similar location of changes in the image of the sacroiliac (anterior) joint.
Supplementary Material
Contributor Information
Sabine Guehery, Department of Radiology, Toulouse University Hospital, Paul Sabatier University, Toulouse III, Toulouse, France.
Julian Plenard, Department of Rheumatology, Toulouse University Hospital, Centre d’Investigation Clinique de Toulouse CIC1436, Inserm, Paul Sabatier University, Toulouse III, Toulouse, France.
François Lafourcade, Department of Radiology, Toulouse University Hospital, Paul Sabatier University, Toulouse III, Toulouse, France.
Franck Lapegue, Department of Radiology, Toulouse University Hospital, Paul Sabatier University, Toulouse III, Toulouse, France.
Laurent Zabraniecki, Department of Rheumatology, Toulouse University Hospital, Centre d’Investigation Clinique de Toulouse CIC1436, Inserm, Paul Sabatier University, Toulouse III, Toulouse, France.
Arnaud Constantin, Department of Rheumatology, Toulouse University Hospital, Centre d’Investigation Clinique de Toulouse CIC1436, Inserm, Paul Sabatier University, Toulouse III, Toulouse, France.
Nicolas Sans, Department of Radiology, Toulouse University Hospital, Paul Sabatier University, Toulouse III, Toulouse, France.
Adeline Ruyssen Witrand, Department of Rheumatology, Toulouse University Hospital, Centre d’Investigation Clinique de Toulouse CIC1436, Inserm, Paul Sabatier University, Toulouse III, Toulouse, France.
Marie Faruch Bilfeld, Department of Radiology, Toulouse University Hospital, Paul Sabatier University, Toulouse III, Toulouse, France.
Supplementary material
Supplementary material is available at Rheumatology Advances in Practice online.
Data availability
The data on which this article are based cannot be made public in order to protect the privacy of the individuals who participated in the study. It will be provided upon reasonable request to the corresponding author.
Author contributions
Conception and design, acquisition of data, and analysis and interpretation of data: S.G. and J.P. Drafting or revising the article critically for important intellectual content: S.G., A.R.W., and M.F.B. Final approval of the version to be published: S.G., J.P., F.Laf., F.Lap., L.Z., A.C., N.S., A.R.W., and M.F.B. Agree to take responsibility for all aspects of the work if questions arise about its accuracy or integrity: S.G., A.R.W., and M.F.B.
Funding
No specific funding was received from any bodies in the public, commercial or not-for-profit sectors to carry out the work described in this article.
Disclosure statement: The authors have declared no conflicts of interest.
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Data Availability Statement
The data on which this article are based cannot be made public in order to protect the privacy of the individuals who participated in the study. It will be provided upon reasonable request to the corresponding author.