Research Presentation Session: Musculoskeletal

RPS 1610 - Pelvis, hip, and bone lesions

March 1, 16:00 - 17:30 CET

7 min
Can we differentiate acute osteomyelitis and vaso-occlusive crises in sickle cell disease patients?
Florian Nabet, Paris / France
Author Block: F. Nabet; Paris/FR
Purpose: Vaso-occlusive crisis (VOC) is the most common complication in individuals with sickle cell disease (SCD), but distinguishing it from acute osteomyelitis, which is also frequent, poses a daily clinical challenge. Some rare forms of VOC, localised in the periosteum (pVOC), are also difficult to differentiate from osteomyelitis with clinico-biological features. The aim of this study was to better characterise these two entities with imaging to improve the management of these fragile patients, particularly to avoid overly frequent antibiotic use.
Methods or Background: From 2008 to 2023, 32 SCD patients with painful periosteal crisis and available MRI data were included (15 women), ranging in age from 17 to 39, with a baseline haemoglobin level of 8.25 (8-8.8), 27 (85%) with SS genotype and 16 (50%) with Bantu/Bantu haplotype. The formal diagnosis (osteomyelitis vs pVOC) was confirmed by the clinician team. In imaging, two independent radiologists blindly reviewed the MRIs and recorded simple descriptive criteria, including the presence or absence of subperiosteal collections, their size, cortical abnormalities, soft tissue oedema, circumferential character, T1 signal with fat saturation, T2 signal, type of enhancement, and associated bone marrow abnormality.
Results or Findings: T1 hyperintensity with fat signal saturation was exclusively found in cases of periosteal pVOC (8 cases, 42,9 % of pVOC cases). Furthermore, circumferential oedema was never observed in cases of pVOC (3 cases, 57,1% of osteomyelitis cases). Interobserver reproducibility was very good (Cohen's kappa = 0.82).
Conclusion: MRI appears to be a valuable tool to differentiate VOC and osteomyelitis in SCD patients with painful periosteal crises.
Limitations: This is a retrospective monocentric study with some missing data.
Within our data set, there seems to be a higher proportion of SCD patients with vaso-occlusive phenotype than in the general SCD population.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the HEGP ethics committee.
7 min
Hip muscle size and density are associated with trochanteric fractures of elderly women
Pengju Huang, Beijing / China
Author Block: P. Huang, Y. Ge, A. Yu, L. Wang, X. Cheng; Beijing/CN
Purpose: We aimed to investigate the differences in hip muscle area and density between older patients with femoral neck (FNF) and trochanteric fractures (TRF)
Methods or Background: A total of 554 older women patients were enrolled, including 314 FNF (77.02 ± 7.15 years) and 240 TRF (79.70 ± 6.91 years) for the comparisons. The area and density of the gluteus medius and minimus muscle (G.Med/MinM) and the gluteus maximus muscle (G.MaxM) were measured by CT. Total hip (TH) areal bone mineral density (aBMD) and femoral neck aBMD (FNaBMD) were measured by quantitative CT. A cut-off of 80 years was used to stratify the cohort and to further explore the age-specific relationship.
Results or Findings: For the total subjects, all these muscle parameters were higher in the FNF group than in the TRF group (P <0.001). The muscle parameters except for the G.Med/MinM density were significantly correlated with hip fracture typing after adjustment for age, BMI, and THaBMD. In the age ≧ 80 group, no statistically significant correlation was found between all hip muscle parameters and fracture types. In contrast, in the age < 80 group, interestingly, after adjustment for age, BMI, and THaBMD, the associations between G.MaxM density, G.MaxM area, G.Med/MinM density, and G.Med/MinM area and fracture type were all statistically significant.
Conclusion: Our results indicate that in older women, especially under 80 years of age, gluteus muscle parameters are related to trochanteric fractures.
Limitations: Firstly, this study features a cross-sectional design, and subsequent longitudinal cohort studies are warranted to further investigate the relationship between gluteal muscles and fracture types. Secondly, in the measurement, we chose to measure the healthy side to replace the data on the fractured side, which may be biased.
Funding for this study: This work is supported in part by the National Key Research and Development Program of China (No. 2020YFC2004902), National Key R&D Program of China (2021YFC2501700), National Natural Science Foundation of China (grant no. 81971617), Beijing Hospitals Authority Youth Programme (code: 20200402), and Beijing Hospitals Authority Clinical Medicine Development of Special Funding Support (code: ZYLX202107).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information:This study was approved by the ethics committee of Beijing Jishuitan Hospital.
7 min
Long-term active MRI-surveillance of low-grade central cartilage tumours of the long bones: towards an optimal assessment of imaging characteristics
Jacoba De Rooy, Nijmegen / Netherlands
Author Block: J. De Rooy, C. Deckers, D. Koopmanschap, E. Dierselhuis, B. Schreuder, I. Van der Geest, M. Prokop; Nijmegen/NL
Purpose: Determining MRI characteristics that contribute to the understanding of the natural course of low-grade central cartilage tumours (CCTs) of the long bones during long-term active MRI-surveillance.
Methods or Background: 92 patients (31 male, 61 female) with 92 low-grade CCTs with a minimum MR imaging follow-up of 48 months (range: 48-174, mean: 74.7) and at least one baseline and one follow-up MRI were retrospectively included. Patient age at diagnosis was 20 to 76 years (mean: 50.4 years); no aggressive MR features (cortical destruction, soft tissue mass) were present and no biopsy had been performed. MRI characteristics (size, cortical scalloping < or ≥ 10% of circumference, intralesional fat entrapment (FE); fatty replacement (FR) only on last MRI) were scored and CCTs were labelled as in regression (R; increasing FE and/or FR, decreasing size (>3mm), in progression (P; loss of FE and/or increasing size (>3mm), increasing scalloping) or stable (S).
Results or Findings: The majority of low-grade CCTs were labelled S or R (81/92, 88%); 68 out of 92 patients showed initial FE (74%) and 29/68 also showed FR. Out of 24 patients without initial FE, 13 (54%) developed FE over time and 8/13 also developed FR. Out of 11 patients (mean 33.4 years, 20-56 years) with growth (P, 12%), 6 showed initial FE (2/6 developing FR) and 4 developed FE (3/4 also developing FR). 1 CCT with developing FE showed new scalloping. Only one CCT showed growth without FE. None developed aggressive MRI characteristics.
Conclusion: Active MRI-surveillance can be safely recommended for low-grade CCTs of the long bones as none developed aggressive MRI characteristics during long-term follow-up. MRI characteristics FE and FR might predict benign behaviour of CCTs and should be assessed on follow-up MRI.
Limitations: This is a retrospective study.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the institutional Review Board of Radboud University Medical Center.
7 min
Metal artifact reduction strategies for clinical photon counting computed tomography of total hip arthroplasty: a volumetric quantitative and qualitative phantom study
Roy P. Marcus, Zurich / Switzerland
Author Block: R. P. Marcus, G. C. Feuerriegel, A. A. Marth, D. Nanz, R. Sutter; Zurich/CH
Purpose: The purpose of this study was to systematically evaluate the impact of various scanning and reconstruction modes on both metal artifact volume and overall image quality in the context of a hip prosthesis phantom, acquired on a first generation clinical photon-counting detector computed tomography (PCCT).
Methods or Background: A total hip prosthesis phantom was scanned on a PCCT (Naeotom Alpha, Siemens Healthineers) employing four distinct modes at 140 kV and constant dose of 7 mGy: Quantumplus (Q+), UHR-Quantumplus (UHR-Q+), QuantumSn (Q-Sn) and UHR-QuantumSn (UHR-Q-Sn); Sn = tin filter. Polychromatic and virtual monoenergetic images (VMI) were reconstructed with and without iterative metal artifact reduction (iMAR, Siemens Healthineers). Artifacts were quantified using a 3D printing software and image quality was evaluated by two radiologists.
Results or Findings: Tin filter reduced artifact volume in polychromatic reconstructions by 14% (298 ml (Q-Sn) vs 347 ml (Q+) and 310 ml (UHR-Q-Sn) vs 360 ml (UHR-Q+)). iMAR reduced the metal artifact volume by 46 – 57% with UHR-Q+ images achieving the lowest artifact volume at 150 ml. In VMI, the smallest total artifact volume was quantified at 130 keV with Q+ (150 ml) and UHR-Q+ (164 ml), at 120 keV with Q-Sn (169 ml) and UHR-Q-Sn (172 ml). iMAR reduced artifact volume in VMI: 130 ml in Q+ (150 keV), 140 ml in UHR-Q+ (160 keV), 134 ml in Q-Sn (150 keV) and 140 ml (UHR Q-Sn at 190 keV). Best subjective image quality was achieved for VMI Q+ with iMAR (65 keV), polychromatic UHR-Q+ with iMAR, VMI Q-Sn with iMAR (100 keV), polychromatic Q-Sn with iMAR, VMI UHR-Q-Sn (100 keV) and polychromatic UHR Q-Sn.
Conclusion: VMI or polychromatic images using tin filter, UHR and iMAR achieve the strongest artifact reduction and best image quality.
Limitations: This was a single phantom size study.
Funding for this study: This study received in house funding.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This was a phantom study, hence no ethics committee approval was needed.
7 min
Evaluation of lower extremity skeletal muscle fibrosis in peripheral arterial disease (PAD) using extracellular volume fraction (ECV) from dual-layer spectral CT
Ningning Ding, Xi'an / China
Author Block: N. Ding, L. Zhou, X. Zhang, Y. Han, Y. Cui, X. Huang, P. Cao, X. Zhang, J. Yang; Xi'an/CN
Purpose: Objectives Peripheral arterial disease (PAD) is characterised by arterial occlusion and fibrosis in the lower extremities. While extracellular volume fraction (ECV) obtained from dual-layer spectral CT has been established as a biomarker for myocardial fibrosis, its application in assessing lower extremities affected by PAD remains unexplored. This study aimed to assess the clinical feasibility of employing ECV for quantifying calf muscle fibrosis and comparing it between normal controls (NC) and PAD patients.
Methods or Background: From October 2022 to February 2023, we recruited patients with PAD as well as sex and age-matched diabetics without peripheral arterial disease (ankle/brachial index >0.9, and<1.3 ) as a control group. All participants underwent late iodine enhancement on lower extremity dual-layer spectral CT to determine the ECV of their calf muscles and the differences between the NC and PAD groups.
Results or Findings: A total of 53 patients (20 in the NC group and 33 in the PAD group) were recruited. The NC group exhibited significantly lower mean ECV compared to the PAD group (19.05% vs 28.89%, respectively, P < 0.001). Among PAD patients, those with collateral vessels had a slightly lower mean ECV than those without (26.89% vs 30.82%, respectively, P = 0.042). Additionally, patients with intermittent claudication in the PAD group had lower mean ECV values compared to patients with critical limb ischaemia (26.98% vs 33.52%, respectively, P = 0.028).
Conclusion: The evaluation of skeletal muscle fibrosis in PAD using ECV obtained from dual-layer spectral CT is both feasible and informative. ECV serves as a valuable tool in identifying the severity of PAD and assessing collateral vessel formation in affected patients.
Limitations: No limitations were identified.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the ethics committee of the First Affiliated Hospital (ethics approval number: XJTUIAF2021LSY-223).
7 min
Monostotic metachronous osteoid osteoma
Sara Battisti, Arqua' Petrarca / Italy
Author Block: S. Battisti, G. Bisinella; Monselice/IT
Purpose: Osteoid osteoma (OO) is a benign bone forming tumour, which very infrequently has multifocal or multicentric presentation.
Multiple nidi may be present close to each other in a single bone or in adjacent bones, or may be present in separate bones in multicentric lesions. We report five unusual cases of double localisation of osteoid osteoma in the same bone after a mean of three years interval (1-5 years). Further studies may establish a systemic etiology and associated morbidities.
Methods or Background: From 2008, we treated 83 cases of osteoid osteoma with CT-guided radiofrequency thermal ablation. We used a 17 gauge needle; the RF was activated for 8 minutes using a temperature of 90 degrees C°.
From 2016 to 2023 we retrospectively evaluated all cases with pain relapse after treatment. We found 8 patients (9.6%) with pain relapse out of a total of 83.
Results or Findings: The analysis of CT images showed that in 5 cases (62%) there was a second nidus close to the first one.
Conclusion: In conclusion, this is the first series of both monostotic and metachronous OO, also associated with pain relapse. Our case highlights the importance of considering a diagnosis of double nidus.
Limitations: The limitation of our retrospective study is the small sample size. Further studies with a larger sample size are needed to confirm our results.
Funding for this study: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This case report was approved by our Institutional review board and patients' informed consent was obtained.
7 min
Hip MRI in flexion abduction external rotation (FABER) position for assessment of the ischiofemoral interval in patients with hip pain: a feasibility study
Florian Schmaranzer, Bern / Switzerland
Author Block: A. Heimann1, T. D. Lerch2, M. Tannast1, S. Steppacher2, M. Wagner3, E. Schmaranzer3, F. Schmaranzer4; 1Fribourg/CH, 2Bern/CH, 3Sankt Johann in Tirol/AT, 4Zurich/CH
Purpose: The purpose of this study was to assess the feasibility of flexion-abduction-external rotation (FABER) magnetic resonance imaging (MRI) of the hip to visualise changes in the ischiofemoral interval.
Methods or Background: This is an IRB-approved retrospective single-centre study. Patients underwent non-contrast 1.5 T hip MRI in the neutral and FABER position. Two readers measured the ischiofemoral interval at three levels: proximal-/distal intertrochanteric distance and ischiofemoral space. Subgroup analysis was performed for hips with (>30°) /without high femoral torsion (<30°), or quadratus femoris muscle oedema (QFME), respectively. A receiver operating curve with calculation of the area under the curve (AUC) for prediction of QFME was calculated.
Results or Findings: 110 patients (121 hips, mean age 34 ± 11 years, 67 females) were evaluated. FABER-MRI led to narrowing (both P < 0.001) of the ischiofemoral interval, which decreased more at the proximal (mean decrease by 26 ± 7 mm) than at the distal (6 ± 7 mm) intertrochanteric ridge. With high femoral torsion/QFME, the ischiofemoral interval was significantly narrower at all
three measurement locations compared to normal torsion/no QFME (P <0.05). Accuracy for predicting QFME was high with an AUC of 0.89 (95% CI 0.82 – 0.94) using a threshold of ≤ 7 mm for the proximal intertrochanteric distance.
Conclusion: Hip MRI in the FABER position is feasible, visualises narrowing of the ischiofemoral interval and may be helpful in diagnosing ischiofemoral impingement.
Limitations: This is a feasibility study; the value of MRI in FABER position needs to be further assessed in a large group of patients with ischiofemoral impingement.
Funding for this study: This study was partially funded by the Swiss national science foundation.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the medical university of Innsbruck.
7 min
Are degenerative findings detected on traction MR arthrography of the hip associated with failure of arthroscopic femoroacetabular impingement surgery?
Florian Schmaranzer, Bern / Switzerland
Author Block: T. D. Lerch1, A. Heimann2, M. Wagner3, P. Vavron3, S. Steppacher1, M. Tannast2, E. Schmaranzer3, F. Schmaranzer4; 1Bern/CH, 2Fribourg/CH, 3Sankt Johann in Tirol/AT, 4Zurich/CH
Purpose: The purpose of this study was to identify preoperative degenerative features on traction MR arthrography associated with failure after arthroscopic femoroacetabular impingement (FAI) surgery.
Methods or Background: This was a retrospective study including 102 patients (107 hips) undergoing traction magnetic resonance arthrography (MRA) of the hip at 1.5T and subsequent hip arthroscopic FAI surgery performed from January 2016 to February 2020, with complete follow-up. Clinical outcomes were assessed using the International Hip Outcome Tool (iHOT-12) score. Clinical endpoint for failure was defined as an iHOT-12 of <60 points or conversion to total hip arthroplasty. MR images were assessed by two radiologists for presence of 9 degenerative lesions including osseous, chondro-labral/ ligamentum teres lesions. Uni- and multivariate Cox regression analysis was performed to assess the association between MRI findings and failure of FAI surgery.
Results or Findings: Of the 107 hips, 27 hips (25%) met at least one endpoint at mean 3.7 ± 0.9 years follow-up. Osteophytic changes of femur or acetabulum (hazard ratio [HR] 2.5 - 5.0), acetabular cysts (HR 3.4) and extensive cartilage (HR 5.1) - and labral damage (HR 5.5) >2 hours on clockface were univariate risk factors (all P <0.05) for surgery failure. Three risk factors for failure were identified in the multivariate analysis: Acetabular cartilage damage > 2 hours on the clockface (HR 3.2, P = 0.01), central femoral osteophyte (HR 3.1, P = 0.02), and femoral cartilage damage with ligamentum teres damage (HR 3.0, P = 0.04).
Conclusion: Evaluation of negative predictors on preoperative traction MR arthrography holds the potential to improve risk stratification based on the already present joint degeneration ahead of FAI surgery.
Limitations: No comparison was possible to non-contrast MRI of the hip or direct MR arthrography without traction.
Funding for this study: This study was partially funded by the Swiss national science foundation.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The institutional review board of the medical university of Innsbruck approved this study.
7 min
Decentration of the femoral head: is it associated with osseous deformities predisposing to hip instability?
Florian Schmaranzer, Bern / Switzerland
Author Block: F. Schmaranzer1, A. Heimann2, S. Steppacher3, M. Tannast2, T. D. Lerch3; 1Zurich/CH, 2Fribourg/CH, 3Bern/CH
Purpose: To assess the prevalence of "decentration of the femoral head" on different imaging planes and compare it between hip deformities.
Methods or Background: IRB-approved retrospective diagnostic study in 351 patients (48% men, mean age 31 ± 12 years) with hip pain undergoing radiography and direct hip MR arthrography at 1.5T (sagittal-, axial-, and radial- PD-w TSE images). On radiographs, lateral centre edge angle and neck-shaft angle were measured. On MRI, measurements of femoral torsion were performed at the level of the lesser trochanter. The presence of decentration was defined as a layer of contrast agent between the posterior femoral and acetabular cartilage layer. The prevalence of decentration sign was compared between sagittal, axial, and radial images and between hips with/without hip dysplasia (lateral centre edge angle, LCE <25°), coxa antetorta (>39°) and valgus hips (neck-shaft angle >139°).
Results or Findings: Decentration was detected with the highest (P <0.001) frequency on radial (28%), followed by axial (13%) and sagittal (5%) images. Hips with decentration sign had a lower LCE angle (24 ± 9° vs 32 ± 7°; P <0.001), higher neck-shaft angle (134 ± 7° vs 131 ± 6°; P <0.001) and higher femoral torsion (24 ± 15° vs 16 ± 12°; P <0.001) than hips without decentration sign. Hips with decentration had a higher prevalence and were associated with hip dysplasia (56% vs 17%, OR of 6.4; P <0.001), coxa antetorta (18% vs 5%, OR of 4.2; P <0.001) and valgus deformity (24% vs 8%, OR of 3.8; P <0.001) compared to hips without decentration sign on MRI.
Conclusion: Decentration sign of the femoral head was most frequently detected on radial MR arthrography and was associated with osseous deformities predisposing to hip instability.
Limitations: The prevalence of decentration signs is unknown in asymptomatic volunteers.
Funding for this study: This study was partially funded by the Swiss National Science Foundation.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Institutional review board approval was granted by the University of Bern.
7 min
The overlooked symptom coccydynia: evaluation of sacrococcygeal morphologic and morphometric findings
Abdullah Şükün, Antalya / Turkey
Author Block: A. Şükün1, H. S. Öztoprak Çubuk2, T. Cankurtaran2, B. Yavuz2, B. Yağdıran2, C. Incekas2; 1Antalya/TR, 2Ankara/TR
Purpose: Coccydynia is one of the most overlooked symptoms in daily clinical practice. Definitions for radiologic evaluation are controversial.
We aim to compare the morphology and morphometric measurements of the sacrococcygeal region with those of a healthy population to support radiologic decision making.
Methods or Background: 26 traumatic and 50 idiopathic patients and 74 healthy controls were compared. The morphologic type of the coccyx, the presence of fusion, and the number of coccygeal segments were evaluated in both groups. Morphometric parameters such as sacrococcygeal angle (SCA), sacrococcygeal joint angle (SCJA), intercoccygeal angle (ICA), sacral slope (SS), coccyx curved length (CCL), sacrum curved length (SCL), coccyx length (CL), sacrum length (SL), and sacrococcygeal total length (SCTL) were investigated.
Results or Findings: Significant differences were found between the Coccydynia group and the healthy control group in morphologic parameters such as female gender, coccyx segment, coccyx morphology, presence of sacrococcygeal joint, and segment of sacrococcygeal joint fusion (p <0.05). In morphologic measurements, sacrococcygeal joint angle, sacrum curved length, sacrum length, coccyx, and sacrum curvature indexes were significantly increased (P <0.05). No significant difference was found in the morphologic and morphometric parameters evaluated when compared with the duration of coccydynia (P >0.05).
Conclusion: An increase in sacrococcygeal joint angle (SCJA), sacrum curved length (SCL), sacrum length (SL), sacrum curvature index (SCI), and coccyx curvature index (CCI) measurements predisposes to coccydynia. It would be more accurate to perform a radiologic evaluation by becoming familiar with these morphologic and morphometric parameters.
Limitations: The limitations of our study are that it is single-centre and retrospective. In our study, CT and MR images of healthy populations were compared and certain static parameters were evaluated. However, coccydynia is a dynamic pathology and dynamic radiological radiographs are needed for evaluation.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Institutional Review Board of Baskent University (Project no: KA23/07).

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