Ligaments injuries check-up and assessment of their healing potential in simple posterolateral elbow dislocation: about 25 cases.

INTRODUCTION: Elbow dislocation can lead to instability and stiffness of the elbow. The main goal of this study was to list the initial elbow ligaments injuries caused by simple posterolateral elbow dislocations. The secondary goals were to assess ligament healing 2 months after the initial dislocation, to research a correlation between ligaments injuries and clinical course, and to search for predictive factors of instability. PATIENTS AND METHODS: Patients who had simple posterolateral elbow dislocation for the first time between January 2015 and May 2016 were included. Each patient had an MRI scan of their traumatised elbow on the day of the dislocation and then again 2 months later. The assessment was performed thanks to a clinical examination and calculation of functional recovery scores. The Mann-Whitney U test was used to research a correlation between the healing of ligaments injuries and clinical course. RESULTS: Twenty-five patients were included in the study. The initial MRI scans showed 70% and 54% ligament rupture, respectively, for the anterior band (ant MCL) and the posterior band (post MCL) of the medial collateral ligament (MCL), as well as 79% for the ulnar (ULCL) and 50% for the radial (RLCL) lateral collateral ligaments. The healing rate 2 months after dislocation was fairly low from 18% for the ULCL up to 41% for the anterior band of the MCL. No correlation was found between the ligament healing noticeable on MRI scans and clinical course. No elbow instability was diagnosed during the 4-month follow-up. CONCLUSION: Elbow dislocation is particularly damaging for ligaments. There is no predominance on medial or lateral ligament for rupture. The low healing rate 2 months after the initial dislocation could be explained by performing a follow-up MRI scan too early.

Dynamic contrast-enhanced MRI perfusion of normal muscle in adult hips: Variation of permeability and semi-quantitative parameters.

The purpose of this prospective study was to ascertain the degree of variation of semi-quantitative and permeability parameters on DCE-MRI of normally appearing striated muscles. Dynamic contrast-enhanced MRI of the right hip was performed in 20 women and 24 men. Mean age was 39.1 ± 12.4 years. Two regions of interest (ROI) were drawn in twelve muscles of anterior, medial and gluteal compartments: a free-form ROI covering the largest muscle section and a smaller elliptical ROI. Semi-quantitative and permeability parameters were calculated using the extended Tofts model. Statistical analysis was performed with a linear mixed model to assess perfusion parameters variation. Intra- and inter-observer agreements were assessed. The intra-observer agreement was considered to be good for free-form ROI (minimum Intra-Class Coefficient (ICC) = 0.72) and moderate for elliptical ROI (minimum ICC = 0.51), while the inter-observer agreement was considered to be bad in both cases (minimum ICC = 0.11). There was a high inter-individual variation in most of the perfusion parameters evaluated. The average coefficients of variation were: Time To Peak = 9%, Area Under the Curve = 44%, Ve = 61%, Kep = 90%, Initial Slope = 99%, and Ktrans = 128%. A considerable variation in resting muscle perfusion parameters was seen. This could lead to errors in the analysis of muscle DCE-MRI studies or oncologic/non oncologic studies using muscle as a referential. Further studies targeted on acquisition protocols and post-processing software are necessary to improve the performance of muscle MR perfusion.

Sacroiliac joints: anatomical variations on MR images.

OBJECTIVE: To describe the appearance of the anatomical variations of the sacroiliac joints (SIJ) on MR images and to highlight the potential MR features that might be misleading. METHODS: Consecutive MRI examinations of SIJs performed at our department from January 2015 to December 2016 were retrospectively analyzed. As one of our goals was to describe potential misleading edematous or structural changes associated with SIJ anatomical variations, patients fulfilling the ASAS criteria were excluded from this study to ensure that signal intensity changes would not be related to sacroiliitis. Five anatomical variations and a dysmorphic appearance of the SIJ were detected. RESULTS: The final group consisted of 157 patients. Unilateral or bilateral anatomical variations of the SIJ were found in 50 patients (accessory SIJ, iliosacral complex and sacral defect in 17, 18 and 21 patients, respectively, and synostosis in one patient). A dysmorphic appearance of the SIJ was found in 26 patients. No case of an unfused ossification centers was depicted. Structural and/or edematous changes of the facing bones were quite frequently observed in accessory and dysmorphic SIJ. Iliosacral complex and sacral defects could be associated with prominent vessels running along their bony surfaces. CONCLUSION: Several anatomical variations of the SIJs are relatively commonly seen on MR images, particularly in females. These variations may be associated with signal intensity changes, which may be mechanical and not necessarily inflammatory in nature. KEY POINTS: • Anatomical variations of SIJ may involve the cartilaginous or ligamentous part of the joint • Anatomical variations of SIJ are sometimes associated with edematous and/or structural changes of the adjacent bone • Anatomical variations of the SIJ can be misleading on MR imaging.

Study of proximal femoral bone perfusion with 3D T1 dynamic contrast-enhanced MRI: a feasibility study.

OBJECTIVE: The objective of this study was to compare measurements of semi-quantitative and pharmacokinetic parameters in areas of red (RBM) and yellow bone marrow (YBM) of the hip, using an in-house high-resolution DCE T1 sequence, and to assess intra- and inter-observer reproducibility of these measurements. METHODS: The right hips of 21 adult patients under 50 years of age were studied. Spatial resolution was 1.8 × 1.8 × 1.8 mm(3), and temporal resolution was 13.5 seconds. Two musculoskeletal radiologists independently processed DCE images and measured semi-quantitative and pharmacokinetic parameters in areas of YBM and RBM. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Intra- and inter-observer reproducibility was assessed. RESULTS: Area under the curve (AUC) and initial slope (IS) were significantly greater for RBM than for YBM (p < 0.05). K(trans) and kep were also significantly greater for RBM (p < 0.05). There was no significant difference in time to peak between the regions (p < 0.05). SNR, CNR, and intra- and inter-observer reproducibility were all good. CONCLUSIONS: DCE study of the whole hip is feasible with high spatial resolution using a 3D T1 sequence. Measures were possible even in low vascularized areas of the femoral head. K(trans), kep, AUC, and IS values were significantly different between red and yellow marrow, whereas TTP values were not. KEY POINTS: High-spatial-resolution dynamic contrast-enhanced MRI of hip structures is feasible. Intra- and inter-observer reproducibility is good. Red and yellow bone marrow have different perfusion patterns.