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Osteoporosis circumscripta is sometimes observed at the skull vault and corresponds to the initial stage of Paget's disease of the bone. Differentiating osteoporosis circumscripta from other reasons for osteolytic images of the vault may be difficult. We report a case of osteoporosis circumscripta of the frontal bone. A lucent rim seen on CT scan, which was enhanced on gadolinium-enhanced MRI, delineated the abnormal bone. The patient was a 50-year-old woman who had CT scans of the skull for chronic sinusitis. Pathology examination showed typical bone changes of Paget's disease. The lucent and enhancing rim sign may help in differentiating Paget's disease from other conditions.

The radiological assessment of muscle properties-size, mass, density (also termed radiodensity), composition, and adipose tissue infiltration-is fundamental in muscle diseases. More recently, it also became obvious that muscle atrophy, also termed muscle wasting, is caused by or associated with many other diseases or conditions, such as inactivity, malnutrition, chronic obstructive pulmonary disorder, cancer-associated cachexia, diabetes, renal and cardiac failure, and sarcopenia and even potentially with osteoporotic hip fracture. Several techniques have been developed to quantify muscle morphology and function. This review is dedicated to quantitative computed tomography (CT) of skeletal muscle and only includes a brief comparison with magnetic resonance imaging. Strengths and limitations of CT techniques are discussed in detail, including CT scanner calibration, acquisition and reconstruction protocols, and the various quantitative parameters that can be measured with CT, starting from simple volume measures to advanced parameters describing the adipose tissue distribution within muscle. Finally, the use of CT in sarcopenia and cachexia and the relevance of muscle parameters for the assessment of osteoporotic fracture illustrate the application of CT in two emerging areas of medical interest.

Percutaneous vertebral augmentation/consolidation techniques are varied. These are vertebroplasty, kyphoplasty, and several methods with percutaneous introduction of an implant (associated or not with cement injection). They are proposed in painful osteoporotic vertebral fractures and traumatic fractures. The objectives are to consolidate the fracture and, if possible, to restore the height of the vertebral body to reduce vertebral and regional kyphosis. Stabilization of the fracture leads to a reduction in pain and thus restores the spinal support function as quickly as possible, which is particularly important in the elderly. The effectiveness of these interventions on fracture pain was challenged once by two randomized trials comparing vertebroplasty to a sham intervention. Since then, many other randomized studies in support of vertebroplasty efficacy have been published. International recommendations reserve vertebroplasty for medical treatment failures on pain, but earlier positioning may be debatable if the objective is to limit kyphotic deformity or even reexpand the vertebral body. Recent data suggest that in osteoporotic fracture, the degree of kyphosis reduction achieved by kyphoplasty and percutaneous implant techniques, compared with vertebroplasty, is not sufficient to justify the additional cost and the use of a somewhat longer and traumatic procedure. In young patients with acute traumatic fractures and a significant kyphotic angle, kyphoplasty and percutaneous implant techniques are preferred to vertebroplasty, as in these cases a deformity reduction has a significant positive impact on the clinical outcome.

One of the most important characteristic of knee osteoarthritis (OA) is the joint space (JS) width narrowing. Measurements are usually performed on two dimensional (2D) X-rays. We propose and validate a new method to assess the 3D joint space at the medial knee compartment using high resolution peripheral computed tomography images. A semi-automated method was developed to obtain a distance 3D map between femur an tibia with the following parameters: volume, minimum, maximum, mean, standard deviation, median, asymmetry, and entropy. We analyzed 71 knee specimens (mean age: 85 years), radiographs were performed for the Kellgren Lawrence (KL) score grading. In a subgroup of 41 specimens, the histopathological Outerbridge and meniscal classifications were performed and then cores were harvested from the tibial plateau in three different positions (posterior, central, and peripheral) and imaged at 10 µm of resolution to measure the cartilage thickness. Minimum, maximum, mean, and median were statistically lower and entropy higher between knee specimens classified as KL = 0 and KL = 3-4. Gr1 and 2 were statistically different from Gr3-4 for minimum, asymmetry, entropy using the Outerbridge classification and Gr1 was statistically different from Gr3-4 using the meniscal classification. Asymmetry, minimum, mean, median and entropy were significantly correlated with cartilage thickness. Parameters extracted from a 3D map of the medial joint space indicate local variations of JS and are related to local measurements of tibial cartilage thickness, and could be consequently useful to identify early OA. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:2380-2391, 2018., (© 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society.)

Objectives: Osteoporotic vertebral fractures are responsible for acute pain and disability that may persist for more than 2 months. We wanted to identify predicting factors for mid-term outcome after vertebroplasty., Methods: We included consecutive patients who underwent vertebroplasty for fragility fractures with persistent and intense pain between January 2014-June 2016. Outcome was assessed by an independent clinician after 1 month using a standardized questionnaire. Patients were classified as having either a favorable or a poor outcome. Presence of an intravertebral cleft and bone oedema mean signal intensity was assessed by an independent radiologist blinded to the clinical data. Pre-intervention clinical or radiological factors were analysed as predictors for outcome., Results: In the 78 included patients (females 71%, age 75 ± 8.3 years), 61.5% had a favourable outcome. When vertebroplasty was performed within 2 months after fracture, the outcome was favourable in 19 patients (39.6%) and poor in five (16.7%; estimate for favourable outcome: OR = 4.1, 95% CI 1.2-13.8, p = 0.021). Absence of intravertebral cleft on pre-intervention imaging was also a predictor of favourable outcome (OR = 3.7, 95% CI 1.2-11.8, p = 0.024). On pre-intervention MRI, vertebral body oedema intensity signal did not influence the outcome., Conclusions: In patients with persistent and intense pain after an osteoporotic vertebral fracture, early intervention and absence of intravertebral cleft were predictors of favourable outcome at 1 month after vertebroplasty., Key Points: • Performing vertebroplasty within 2 months following a fragility fracture increases success rate. • Presence of an intravertebral cleft at baseline is a predictor of poor mid-term outcome. • A pre-intervention MRI should be performed to ascertain the indication of vertebroplasty.

Purpose: The purpose of this study was to evaluate, during a national workshop, the inter-observer variability in target volume delineation for primary extremity soft tissue sarcoma radiation therapy., Methods and Materials: Six expert sarcoma radiation oncologists (members of French Sarcoma Group) received two extremity soft tissue sarcoma radiation therapy cases 1: one preoperative and one postoperative. They were distributed with instructions for contouring gross tumour volume or reconstructed gross tumour volume, clinical target volume and to propose a planning target volume. The preoperative radiation therapy case was a patient with a grade 1 extraskeletal myxoid chondrosarcoma of the thigh. The postoperative case was a patient with a grade 3 pleomorphic undifferentiated sarcoma of the thigh. Contour agreement analysis was performed using kappa statistics., Results: For the preoperative case, contouring agreement regarding GTV, gross tumour volume GTV, clinical target volume and planning target volume were substantial (kappa between 0.68 and 0.77). In the postoperative case, the agreement was only fair for reconstructed gross tumour volume (kappa: 0.38) but moderate for clinical target volume and planning target volume (kappa: 0.42). During the workshop discussion, consensus was reached on most of the contour divergences especially clinical target volume longitudinal extension. The determination of a limited cutaneous cover was also discussed., Conclusion: Accurate delineation of target volume appears to be a crucial element to ensure multicenter clinical trial quality assessment, reproducibility and homogeneity in delivering RT. radiation therapy RT. Quality assessment process should be proposed in this setting. We have shown in our study that preoperative radiation therapy of extremity soft tissue sarcoma has less inter-observer contouring variability., (Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.)

Advances in cancer treatments have lengthened the survival of patients with bone metastases. Optimal control of the symptoms and prevention of the complications associated with bone metastases improve quality of life. Achieving these goals increasingly involves interventional radiology procedures. These include bone consolidation and analgesic techniques such as cementoplasty (vertebroplasty at the spine); percutaneous implantation of screws, metallic reinforcement devices, or intraosseous implants; and tumor destruction using thermal methods (radiofrequency and cryotherapy), chemicals (alcohol), and drugs (chemoembolization), which have fewer indications. Here, these techniques and their indications are reviewed., (Copyright © 2017. Published by Elsevier SAS.)

Objectives: To assess the efficacy of bisphosphonate therapy on bone pain in patients with osteoid osteoma (OO) (main objective), and to describe bisphosphonate-induced changes in nidus mineralisation and regional bone-marrow oedema (BMO)., Methods: A prospective, observational study was conducted from 2011 to 2014. Patients with risk factors for complications of percutaneous or surgical ablation or recurrence after ablation, were offered once monthly intravenous bisphosphonate treatment until significant pain alleviation was achieved., Results: We included 23 patients. The first two patients received pamidronate and the next 21 zoledronic acid (mean, 2.95 infusions per patient). Bisphosphonate therapy was successful in 19 patients (83%), whose mean pain visual analogue scale score decreased by 76.7%; this pain-relieving effect persisted in 17 patients (74%) with a mean follow-up time of 36 months. Computed tomography (CT) demonstrated a mean nidus density increase of 177.7% (p = 0.001). By magnetic resonance imaging (MRI), mean decreases were 38.4% for BMO surface area and 30.3% for signal intensity (p = 0.001 and p = 0.000, respectively)., Conclusions: In 17/23 patients with painful OO managed conservatively with bisphosphonates, long-term final success was achieved. Bisphosphonates may accelerate the spontaneous healing of OO., Key Points: • 19/23 patients with OO managed with bisphosphonates experienced significant pain relief • Pain relief was sustained in 17/23 patients, mean follow-up of 36 months • CT demonstrated a significant increase in nidus mineralisation • MRI demonstrated a significant decrease in bone marrow oedema • Bisphosphonate therapy may accelerate the spontaneous healing of OO.

Objectives: 1. To show that the anterior hip joint space is profiled only on the contralateral false profile radiograph. 2. To provide normal values of hip joint space width on anteroposterior and false profile radiographs. 3. To identify the best sites for joint space radiographic measurements to depict early hip osteoarthritis., Methods: Anteroposterior and bilateral false profile radiographs of a cadaveric pelvis with markers around the anterior part of the hip joint were obtained. Joint space width was measured at ten sites on anteroposterior pelvis and bilateral hip false profile radiographs in 37 patients without hip pain (mean age, 59 years) and 65 patients with hip pain (mean age, 57.5 years), including 30 with and 35 without radiographic osteoarthritic subchondral bone changes. Between-groups differences in joint space width at each site were evaluated using ANOVA. The ability of joint space width at each site to discriminate between patients groups was investigated using logistic regression., Results: The anterior joint space was only profiled on a contralateral false profile radiograph. Presumably, normal joint space widths were obtained in the group without hip pain. Joint space widths measured on the false profile radiographs differed significantly between the patient groups while measurements on the anteroposterior pelvis radiograph did not., Conclusions: Bilateral false profile radiographs profile the entire hip joint space, including its anterior part, and discriminate better between patients with and without hip pain than the anteroposterior pelvis radiograph. The AS/P joint space width ratio (anterosuperior/posterior) was the best parameter., (Copyright © 2016. Published by Elsevier SAS.)

Purpose: To perform a synthesis of articles addressing the role of stretching on roots in the pathophysiology of radiculopathy., Methods: Review of relevant articles on this topic available in the PubMed database., Results: An intraoperative microscopy study of patients with sciatica showed that in all patients the hernia was adherent to the dura mater of nerve roots. During the SLR (Lasègue's) test, the limitation of nerve root movement occurs by periradicular adhesive tissue, and temporary ischemic changes in the nerve root induced by the root stretching cause transient conduction disturbances. Spinal roots are more frail than peripheral nerves, and other mechanical stresses than root compression can also induce radiculopathy, especially if they also impair intraradicular blood flow, or the function of the arachnoid villi intimately related to radicular veins. For instance arachnoiditis, the lack of peridural fat around the thecal sac, and epidural fibrosis following surgery, can all promote sciatica, especially in patients whose sciatic trunks also stick to piriformis or internus obturator muscles. Indeed, stretching of roots is greatly increased by adherence at two levels., Conclusions: As excessive traction of nerve roots is not shown by imaging, many physicians have unlearned to think in terms of microscopic and physiologic changes, although nerve root compression in the lumbar MRI is lacking in more than 10% of patients with sciatica. It should be reminded that, while compression of a spinal nerve root implies stretching of this root, the reverse is not true: stretching of some roots can occur without any visible compression., (Copyright © 2017 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.)

Objective: Cartilage and subchondral bone form a functional unit. Here, we aimed to examine the effect of meniscus coverage on the characteristics of this unit in knees of older individuals., Methods: We assessed the hyaline cartilage, subchondral cortical plate (SCP), and subchondral trabecular bone in areas covered or uncovered by the meniscus from normal cadaver knees (without degeneration). Bone cores harvested from the medial tibial plateau at locations uncovered (central), partially covered (posterior), and completely covered (peripheral) by the meniscus were imaged by micro-CT. The following were measured on images: cartilage volume (Cart.Vol, mm3) and thickness (Cart.Th, mm); SCP thickness (SCP.Th, μm) and porosity (SCP.Por, %); bone volume to total volume fraction (BV/TV, %); trabecular thickness (Tb.Th, μm), spacing (Tb.Sp, μm), and number (Tb.N, 1/mm); structure model index (SMI); trabecular pattern factor (Tb.Pf); and degree of anisotropy (DA)., Results: Among the 28 specimens studied (18 females) from individuals with mean age 82.8±10.2 years, cartilage and SCP were thicker at the central site uncovered by the meniscus than the posterior and peripheral sites, and Cart.Vol was greater. SCP.Por was highest in posterior samples. In the upper 1-5 mm of subchondral bone, central samples were characterized by higher values for BV/TV, Tb.N, Tb.Th, and connectivity (Tb.Pf), a more plate-like trabecular structure and lower anisotropy than with other samples. Deeper down, at 6-10 mm, the differences were slightly higher for Tb.Th centrally, DA peripherally and SMI posteriorly., Conclusions: The coverage or not by meniscus in the knee of older individuals is significantly associated with Cart.Th, SCP.Th, SCP.Por and trabecular microarchitectural parameters in the most superficial 5 mm and to a lesser extent the deepest area of subchondral trabecular bone. These results suggest an effect of differences in local loading conditions. In subchondral bone uncovered by the meniscus, the trabecular architecture resembles that of highly loaded areas.

Objective: To correlate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) features to clinical and computed tomography (CT) morphological features of osteoid osteoma (OO)., Materials and Methods: Our institutional review board approved this retrospective study, waiving the need for informed consent. We included the 102 patients treated with interstitial laser ablation for histologically documented OO at our institution in 2008-2013. DCE-MRI variables were the time-enhancement pattern and rising slope (Slope rise ) and CT variables were the bone and segment involved (OO bone and OO segment, respectively), OO location relative to the native cortex (OO cortex ), nidus surface area, vessel sign, and largest neighboring-vessel diameter (Dmax vessel ). Descriptive statistics and correlations linking DCE-MRI findings to clinical and CT characteristics were computed., Results: DCE-MRI showed early arterial peak enhancement in 95 (93%) cases, with a mean Slope rise of 9.30 ± 8.10. CT visualized a vessel sign in 84 (82%) cases with a mean Dmax vessel of 1.10 ± 0.60 mm. By univariate analysis, Slope rise correlated significantly with pain duration and Dmax vessel (r = 0.30, P = 0.003; and r = 0.22, P = 0.03; respectively). Analysis of variance showed that Slope rise correlated significantly with OO bone (P < 0.001), with a steeper slope for OOs located in short or flat bones., Conclusion: This study suggests more abundant vascularization of OOs with long-lasting pain and location on short or flat bones.

Case: A 48-year-old woman was unable to walk due to an extensive osteolytic supra-acetabular iliac wing metastatic lymphoma involving the arcuate line. A minimally invasive technique that combined percutaneous nailing of the iliac bone with a customized nail and cementoplasty (intraosseous injection of polymethylmethacrylate) was performed. At the 1-year follow-up, she was able to walk without crutches, and computed tomography (CT) showed a stable iliac bone fixation., Conclusion: Osteolytic metastasis is a common cause of bone weakening, especially in load-bearing areas. With osteolytic metastases involving the acetabulum, intraosseous injection of bone cement into the weakened acetabulum may reduce pain and prevent fracture. Nailing combined with cementoplasty may be proposed for extensive destruction of the iliac bone involving the arcuate line to relieve pain and allow for resumed walking.

Many studies use threshold-based techniques to assess in vivo the muscle, bone and adipose tissue distribution of the legs using computed tomography (CT) imaging. More advanced techniques divide the legs into subcutaneous adipose tissue (SAT), anatomical muscle (muscle tissue and adipocytes within the muscle border) and intra- and perimuscular adipose tissue. In addition, a so-called muscle density directly derived from the CT-values is often measured. We introduce a new integrated approach to quantify the muscle-lipid system (MLS) using quantitative CT in patients with sarcopenia or osteoporosis. The analysis targets the thigh as many CT studies of the hip do not include entire legs The framework consists of an anatomic coordinate system, allowing delineation of reproducible volumes of interest, a robust semi-automatic 3D segmentation of the fascia and a comprehensive method to quantify of the muscle and lipid distribution within the fascia. CT density-dependent features are calibrated using subject-specific internal CT values of the SAT and external CT values of an in scan calibration phantom. Robustness of the framework with respect to operator interaction, image noise and calibration was evaluated. Specifically, the impact of inter- and intra-operator reanalysis precision and addition of Gaussian noise to simulate lower radiation exposure on muscle and AT volumes, muscle density and 3D texture features quantifying MLS within the fascia, were analyzed. Existing data of 25 subjects (age: 75.6 ± 8.7) with porous and low-contrast muscle structures were included in the analysis. Intra- and inter-operator reanalysis precision errors were below 1% and mostly comparable to 1% of cohort variation of the corresponding features. Doubling the noise changed most 3D texture features by up to 15% of the cohort variation but did not affect density and volume measurements. The application of the novel technique is easy with acceptable processing time. It can thus be employed for a comprehensive quantification of the muscle-lipid system enabling radiomics approaches to musculoskeletal disorders.

Background: Active discopathy is associated with a specific phenotype of chronic low back pain (LBP). Local inflammation has a role in active discopathy-associated symptoms., Objective: To assess the efficacy of a single glucocorticoid intradiscal injection (GC IDI) in patients with chronic LBP with active discopathy., Design: Prospective, parallel-group, double-blind, randomized, controlled study. (ClinicalTrials.gov: NCT00804531)., Setting: 3 tertiary care centers in France., Patients: 135 patients with chronic LBP with active discopathy on magnetic resonance imaging (MRI)., Intervention: A single GC IDI (25 mg prednisolone acetate) during discography (n = 67) or discography alone (n = 68)., Measurements: The primary outcome was the percentage of patients with LBP intensity less than 40 on an 11-point numerical rating scale (0 [no pain] to 100 [maximum pain] in 10-point increments) in the previous 48 hours at 1 month after the intervention. The main secondary outcomes were LBP intensity and persistent active discopathy on MRI at 12 months and spine-specific limitations in activities, health-related quality of life, anxiety and depression, employment status, and use of analgesics and nonsteroidal anti-inflammatory drugs at 1 and 12 months., Results: All randomly assigned patients were included in the primary efficacy analysis. At 1 month after the intervention, the percentage of responders (LBP intensity <40) was higher in the GC IDI group (36 of 65 [55.4%]) than the control group (21 of 63 [33.3%]) (absolute risk difference, 22.1 percentage points [95% CI, 5.5 to 38.7 percentage points]; P = 0.009). The groups did not differ in LBP intensity at 12 months and in most secondary outcomes at 1 and 12 months., Limitation: Tertiary care setting., Conclusion: In chronic LBP associated with active discopathy, a single GC IDI reduces LBP at 1 month but not at 12 months., Primary Funding Source: French Ministry of Health.

Background: A change of loading conditions in the knee causes changes in the subchondral bone and may be a cause of osteoarthritis (OA). However, quantification of trabecular architecture in vivo is difficult due to the limiting spatial resolution of the imaging equipment; one approach is the use of texture parameters. In previous studies, we have used digital models to simulate changes of subchondral bone architecture under OA progression. One major result was that, using computed tomography (CT) images, subchondral bone mineral density (BMD) in combination with anisotropy and global homogeneity could characterize this progression. The primary goal of this study was a comparison of BMD, entropy, anisotropy, variogram slope, and local and global inhomogeneity measurements between high-resolution peripheral quantitative CT (HR-pQCT) and CT using human cadaveric knees. The secondary goal was the verification of the spatial resolution dependence of texture parameters observed in the earlier simulations, two important prerequisites for the interpretation of in vivo measurements in OA patients., Method: The applicability of texture analysis to characterize bone architecture in clinical CT examinations was investigated and compared to results obtained from HR-pQCT. Fifty-seven human knee cadavers (OA status unknown) were examined with both imaging modalities. Three-dimensional (3D) segmentation and registration processes, together with automatic positioning of 3D analysis volumes of interest (VOIs), ensured the measurement of BMD and texture parameters at the same anatomical locations in CT and HR-pQCT datasets., Results: According to the calculation of dice ratios (>0.978), the accuracy of VOI locations between methods was excellent. Entropy, anisotropy, and global inhomogeneity showed significant and high linear correlation between both methods (0.68 < R 2  < 1.00). The resolution dependence of these parameters simulated earlier was confirmed by the in vitro measurements., Conclusion: The high correlation of HR-pQCT- and CT-based measurements of entropy, global inhomogeneity, and anisotropy suggests interchangeability between devices regarding the quantification of texture. The agreement of the experimentally determined resolution dependence of global inhomogeneity and anisotropy with earlier simulations is an important milestone towards their use to quantify subchondral bone structure. However, an in vivo study is still required to establish their clinical relevance.

In clinical studies, high resolution peripheral quantitative computed tomography (HR-pQCT) is used to separately evaluate cortical bone and trabecular bone with an isotropic voxel of 82 µm 3 , and typical cortical parameters are cortical density (D.comp), thickness (Ct.Th), and porosity (Ct.Po). In vitro, micro-computed tomography (micro-CT) is used to explore the internal cortical bone micro-structure with isotropic voxels and high resolution synchrotron radiation (SR); micro-CT is considered the 'gold standard'. In 16 tibias and 8 femurs, HR-pQCT measurements were compared to conventional micro-CT measurements. To test modality effects, conventional micro-CT measurements were compared to SR micro-CT measurements at 7.5 µm 3 ; SR micro-CT measurements were also tested at different voxel sizes for the femurs, specifically, 7.5 µm 3 versus 2.8 µm 3 . D.comp (r  =  -0.88, p  <  10 -3 ) was the parameter best correlated with porosity (Po.V/TV). The correlation was not affected by the removal of pores under 130 µm. Ct.Th was also significantly highly correlated (r  =  -0.89 p  <  10 -3 ), while Ct.Po was correlated with its counterpart Po.V/TV (r  =  0.74, p  <  10 -3 ). From SR micro-CT and conventional micro-CT at 7.5 µm 3 in matching areas, Po.V/TV and pore diameter were underestimated in conventional micro-CT with mean  ±  standard deviation (SD) biases of  -2.5  ±  1.9% and  -0.08  ±  0.08 mm, respectively. In contrast, pore number (Po.N) and pore separation (Po.Sp) were overestimated with mean  ±  SD biases of  +0.03  ±  0.04 mm -1 and  +0.02  ±  0.04 mm, respectively. The results from the tibia and femur were similar when the results of SR micro-CT at 7.5 µm 3 and 2.8 µm 3 were compared. Po.V/TV, specific surface of pores (Po.S/Po.V), and Po.N were underestimated with mean biases of  -1.7  ±  0.9%, -4.6  ±  4.4 mm -1 , and  -0.26  ±  0.15 mm -1 , respectively. In contrast, pore spacing was overestimated at 7.5 µm 3 compared to 2.8 µm 3 with mean biases of 0.05  ±  0.03 mm. Cortical bone measurements from HR-pQCT images provided consistent results compared to those obtained using conventional micro-CT at the distal tibia. D.comp was highly correlated to Po.V/TV because it considers both the micro-porosity (Haversian systems) and macro-porosity (resorption lacunae) of cortical bone. The complexity of canal organization, (including shape, connectivity, and surface) are not fully considered in conventional micro-CT in relation to beam hardening and cone beam reconstruction artifacts. With the exception of Po.V/TV measurements, morphological and topological measurements depend on the characteristics of the x-ray beam, and to a lesser extent, on image resolution.

Objective: To describe the bone imaging features of lipodystrophies in the largest cohort ever published., Materials and Methods: We retrospectively examined bone imaging data in 24 patients with lipodystrophic syndromes. Twenty-two had genetic lipodystrophy: 12/22 familial partial lipodystrophy (FPLD) and 10/22 congenital generalized lipodystrophy (CGL), 8 with AGPAT2-linked CGL1 and 2 with seipin-linked CGL2. Two patients had acquired generalized lipodystrophy (AGL) in a context of non-specific autoimmune disorders. Skeletal radiographs were available for all patients, with radiographic follow-up for two. Four patients with CGL1 underwent MRI, and two of them also underwent CT., Results: Patients with FPLD showed non-specific degenerative radiographic abnormalities. Conversely, CGL patients showed three types of specific radiographic alterations: diffuse osteosclerosis (in 7 patients, 6 with CGL1 and 1 with CGL2), well-defined osteolytic lesions sparing the axial skeleton (7 CGL1 and 1 CGL2), and pseudo-osteopoikilosis (4 CGL1). Pseudo-osteopoikilosis was the sole bone abnormality observed in one of the two patients with AGL. Osteolytic lesions showed homogeneous low signal intensity (SI) on T1-weighted and high SI on T2-weighted MR images. Most of them were asymptomatic, although one osteolytic lesion resulted in a spontaneous knee fracture and secondary osteoarthritis in a patient with CGL1. MRI also showed diffuse fatty bone marrow alterations in patients with CGL1, with intermediate T1 and high T2 SI, notably in radiographically normal areas., Conclusions: The three types of peculiar imaging bone abnormalities observed in generalized lipodystrophic syndromes (diffuse osteosclerosis, lytic lesions and/or pseudo-osteopoikilosis) may help clinicians with an early diagnosis in pauci-symptomatic patients.

Purpose To evaluate the performance of three imaging methods (radiography, dual-energy x-ray absorptiometry [DXA], and quantitative computed tomography [CT]) and that of a numerical analysis with finite element modeling (FEM) in the prediction of failure load of the proximal femur and to identify the best densitometric or geometric predictors of hip failure load. Materials and Methods Institutional review board approval was obtained. A total of 40 pairs of excised cadaver femurs (mean patient age at time of death, 82 years ± 12 [standard deviation]) were examined with (a) radiography to measure geometric parameters (lengths, angles, and cortical thicknesses), (b) DXA (reference standard) to determine areal bone mineral densities (BMDs), and (c) quantitative CT with dedicated three-dimensional analysis software to determine volumetric BMDs and geometric parameters (neck axis length, cortical thicknesses, volumes, and moments of inertia), and (d) quantitative CT-based FEM to calculate a numerical value of failure load. The 80 femurs were fractured via mechanical testing, with random assignment of one femur from each pair to the single-limb stance configuration (hereafter, stance configuration) and assignment of the paired femur to the sideways fall configuration (hereafter, side configuration). Descriptive statistics, univariate correlations, and stepwise regression models were obtained for each imaging method and for FEM to enable us to predict failure load in both configurations. Results Statistics reported are for stance and side configurations, respectively. For radiography, the strongest correlation with mechanical failure load was obtained by using a geometric parameter combined with a cortical thickness (r(2) = 0.66, P < .001; r(2) = 0.65, P < .001). For DXA, the strongest correlation with mechanical failure load was obtained by using total BMD (r(2) = 0.73, P < .001) and trochanteric BMD (r(2) = 0.80, P < .001). For quantitative CT, in both configurations, the best model combined volumetric BMD and a moment of inertia (r(2) = 0.78, P < .001; r(2) = 0.85, P < .001). FEM explained 87% (P < .001) and 83% (P < .001) of bone strength, respectively. By combining (a) radiography and DXA and (b) quantitative CT and DXA, correlations with mechanical failure load increased to 0.82 (P < .001) and 0.84 (P < .001), respectively, for radiography and DXA and to 0.80 (P < .001) and 0.86 (P < .001) , respectively, for quantitative CT and DXA. Conclusion Quantitative CT-based FEM was the best method with which to predict the experimental failure load; however, combining quantitative CT and DXA yielded a performance as good as that attained with FEM. The quantitative CT DXA combination may be easier to use in fracture prediction, provided standardized software is developed. These findings also highlight the major influence on femoral failure load, particularly in the trochanteric region, of a densitometric parameter combined with a geometric parameter. (©) RSNA, 2016 Online supplemental material is available for this article.

Purpose To determine the in vivo effects of several particulate steroids on microvascular perfusion by using intravital microscopy in a mice model and to investigate the in vitro interactions between these particulate steroids and red blood cells (RBCs). Materials and Methods The study was conducted in agreement with the guidelines of the National Committee of Ethic Reflection on Animal Experimentation. By using intravital microscopy of mouse cremaster muscle, the in vivo effects of several particulate steroids on microvascular perfusion were assessed. Four to five mice were allocated to each of the following treatment groups: saline solution, dexamethasone sodium phosphate, a nonparticulate steroid, and the particulate steroids cortivazol, methylprednisolone, triamcinolone, and prednisolone. By using in vitro blood microcinematography and electron microscopy, the interactions between these steroids and human RBCs were studied. All results were analyzed by using nonparametric tests. Results With prednisolone, methylprednisolone, or triamcinolone, blood flow was rapidly and completely stopped in all the arterioles and venules (median RBC velocity in first-order arterioles, 5 minutes after administration was zero for these three groups) compared with a limited effect in mice treated with saline, dexamethasone, and cortivazol (20.3, 21.3, and 27.5 mm/sec, respectively; P < .003). This effect was associated with a large decrease in the functional capillary density (4.21, 0, and 0 capillaries per millimeter for methylprednisolone, triamcinolone, or prednisolone, respectively, vs 21.0, 21.4, and 19.1 capillaries per millimeter in mice treated with saline, dexamethasone, and cortivazol, respectively; P < .003). This was because of the rapid formation of RBC aggregates. However, no change in microvascular perfusion was associated with administration of cortivazol or dexamethasone. In vitro experiments confirmed the formation of RBC aggregates associated with the transformation of RBCs into spiculated RBCs with the same steroids. Conclusion Several particulate steroids have an immediate and massive effect on microvascular perfusion because of formation of RBC aggregates associated with the transformation of RBCs into spiculated RBCs. (©) RSNA, 2016 Online supplemental material is available for this article.

Objective: At the microscopic level, there is no established 3D method to measure cartilage volume and thickness. An easy, precise and accurate volume and thickness measurements of human cartilage has been developed from micro-computed tomography (micro-CT) images., Design: In the medial tibial plateau of twenty nine left cadaveric knees classified as normal, vertical cores (7 mm in diameter) were extracted in three locations: lateral (LAT), medial posterior (MP) and medial anterior (MA). The cores were imaged in mineral oil with micro-CT (voxel size 10.2 μm) and were measured cartilage volume (Cart.Vol, mm(3)) and cartilage thickness (Cart.Th, mm) using a thickness plugin. Short term reproducibility and standard deviation (ST&#95;RMSCV%, ST&#95;RMSSD, mm) were determined. To assess accuracy, holes with diameters of 2 mm, 3 mm, and 4 mm were artificially generated and nominal and measured hole sizes were compared., Results: Precision of Cart.Vol&#95;ST&#95;RMSCV% was 1.35%. The mean biases between nominal hole volume and measurements were -0.49 ± 1.5 mm(3) (2 mm), -0.41 ± 4.2 mm(3) (3 mm) and +0.34 ± 4.4 mm(3) (4 mm). ST&#95;RMSSD was 100 times lower than the biological variation and the highest bias to measure volume was 24 times lower. Cart.Th results statistically differed among core extraction locations: 1.75 ± 0.28 mm (LAT), 1.84 ± 0.40 mm (MP) and 2.32 ± 0.41 mm (MA)., Conclusion: With a standard laboratory micro-CT system, it was possible to measure cartilage volume and thickness with good precision and accuracy relative to the biological variation of the specimen cohort. Cartilage measurements from micro-CT probably will improve the knowledge of the relationship between cartilage and subchondral bone and may allow to better understand the OA process., (Copyright © 2015. Published by Elsevier Ltd.)

Accurate and reliable assessment of bone quality requires predictive methods which could probe bone microstructure and provide information on bone mechanical properties. Multiscale modelling and simulation represent a fast and powerful way to predict bone mechanical properties based on experimental information on bone microstructure as obtained through X-ray-based methods. However, technical limitations of experimental devices used to inspect bone microstructure may produce blurry data, especially in in vivo conditions. Uncertainties affecting the experimental data (input) may question the reliability of the results predicted by the model (output). Since input data are uncertain, deterministic approaches are limited and new modelling paradigms are required. In this paper, a novel stochastic multiscale model is developed to estimate the elastic properties of bone while taking into account uncertainties on bone composition. Effective elastic properties of cortical bone tissue were computed using a multiscale model based on continuum micromechanics. Volume fractions of bone components (collagen, mineral, and water) were considered as random variables whose probabilistic description was built using the maximum entropy principle. The relevance of this approach was proved by analysing a human bone sample taken from the inferior femoral neck. The sample was imaged using synchrotron radiation micro-computed tomography. 3-D distributions of Haversian porosity and tissue mineral density extracted from these images supplied the experimental information needed to build the stochastic models of the volume fractions. Thus, the stochastic multiscale model provided reliable statistical information (such as mean values and confidence intervals) on bone elastic properties at the tissue scale. Moreover, the existence of a simpler "nominal model", accounting for the main features of the stochastic model, was investigated. It was shown that such a model does exist, and its relevance was discussed.

Radiation-induced sarcoma is a long-term complication of radiation therapy. The most common secondary neoplasia is the undifferentiated pleomorphic sarcoma, which is usually described in the deep soft tissue of the trunk or extremities. Radiation-induced sarcomas have a poor prognosis. An early diagnosis and management are needed to improve the survival rate of such patients. We presently report a case of a radiation-induced undifferentiated pleomorphic sarcoma of the left gluteus maximus muscle, which developed 25 years after an initial diagnosis of aggressive fibromatosis and 21 years after a tumour recurrence. This case study illustrates the risk of developing a sarcoma in a radiation field and the need for long-term follow-up after radiation therapy. Unnecessary radiation therapy, in particular in the case of benign conditions in young patients, should be avoided., (Copyright © 2015 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.)

Purpose: To investigate the efficacy of percutaneous chemonucleolysis using ethanol gel (PCEG) in alleviating radicular pain due to disc herniation after failure of conservative treatment., Materials and Methods: After failure of conservative treatment, PCEG was performed under fluoroscopic guidance in 42 patients with sciatica >4/10 on a Visual Analog Scale (VAS) for at least 6 weeks and consistent disc herniation on MRI or CT <3 months. The VAS pain score was determined at baseline, then after 1 and 3 months. We assessed the influence of patient-related factors (age, gender, pain duration) and disc herniation-related factors (level, migration pattern, disc herniation-related spinal stenosis) on outcome of PCEG., Results: Mean pain duration was 6.7 months. Pain intensity decreased by 44% and 62.6% after 1 and 3 months, respectively, versus baseline (P = 0.007). A mild improvement was noted by the rheumatologist in 30/42 (71.4%) and 36/42 (85.7%) patients after 1 and 3 months, respectively, and in 31/42 (73.8%) and 33/42 (78.6%) patients by self-evaluation. Patients who failed PCEG were significantly older (49.8 vs. 37.3 years, P = 0.03). None of the other variables studied were significantly associated with pain relief., Conclusion: PCEG may significantly improve disc-related radicular pain refractory to conservative treatment., Key Points: • Percutaneous chemonucleolysis using ethanol gel (PCEG) is feasible on an outpatient basis. • PCEG improves disc-related radicular pain refractory to conservative treatment. • PCEG is feasible on an outpatient basis. • Failure of PCEG does not interfere with subsequent spinal surgery.

Purpose: To study the long-term evolution of the bone marrow burden (BMB) score at MRI in patients with Gaucher disease (GD) under enzyme replacement therapy (ERT)., Material and Methods: Forty patients treated for GD were retrospectively studied in a referral centre. BMB scores were assessed on spine and femur MR examinations performed between January 2003 and June 2014. The long-term evolution of the BMB scores was analyzed using a linear mixed model., Results: A total of 121 MRI examinations were performed during the study period with a mean follow-up of 7.1 years ± 5.6, an average rate of 3.1 MR examinations ± 1.7 per patient and an interval of 2.3 years ± 1.1 between examinations. Patients had received ERT during 12 years on average ± 6.7. The trend of BMB scores with time decreased significantly by 15% (P = 0.008) during the total study period and 39% (P = 0.01) during the first 5 years of treatment. No changes in BMB scores were observed after five years of treatment., Conclusion: In Gaucher patients, the trend of MRI BMB scores with time decreased significantly under ERT the first 5 years of treatment before a long-term stabilization., Key Points: • Bone marrow infiltration of Gaucher patients responds to enzyme replacement therapy • MRI BMB score decreases mainly during the first five years of treatment • MRI BMB score tends to stabilize after five years of treatment • MR examinations could be limited after five years of treatment.

Objectives: The objective is to determine if muscle MRI is useful for assessing neuropathy severity., Methods: Clinical, MRI and electromyography (EMG) examinations were performed in 17 patients with focal lower limb neuropathies. MRI Short Tau Inversion Recovery (STIR) signal intensity, amyotrophy, and muscle fatty infiltration measured after T1-weighted image acquisition, EMG spontaneous activity (SA), and maximal voluntary contraction (MVC) were graded using semiquantitative scores and quantitative scores for STIR signal intensity and were correlated to the Medical Research Council (MRC) score for testing muscle strength. Within this population, subgroups were selected according to severity (mild versus severe), duration (subacute versus chronic), and topography (distal versus proximal) of the neuropathy., Results: EMG SA and MVC MRI amyotrophy and quantitative scoring of muscle STIR intensity were correlated with the MRC score. Moreover, MRI amyotrophy was significantly increased in severe, chronic, and proximal neuropathies along with fatty infiltration in chronic lesions., Conclusions: Muscle MRI atrophy and quantitative evaluation of signal intensity were correlated to MRC score in our study. Semiquantitative evaluation of muscle STIR signal was sensitive enough for detection of topography of the nerve lesion but was not suitable to assess severity. Muscle MRI could support EMG in chronic and proximal neuropathy, which showed poor sensitivity in these patients.

The periosteum covers most bone structures. It has an outer fibrous layer and an inner cambial layer that exhibits osteogenic activity. The periosteum is a dynamic structure that plays a major role in bone modeling and remodeling under normal conditions. In several disorders such as infections, benign and malignant tumors, and systemic diseases, the osteogenic potential of the periosteum is stimulated and new bone is produced. The newly formed bone added onto the surface of the cortex adopts various configurations depending on the modalities and pace of bone production. Our aim here is to describe the anatomy, histology, and physiology of the periosteum and to review the various patterns of periosteal reaction with emphasis on relations between radiological and histopathological findings. A careful evaluation of the periosteal reaction and appearance of the underlying cortex, in combination with the MRI, clinical, and laboratory data, provides valuable information on lesion duration and aggressiveness, thereby assisting in the etiological diagnosis and optimizing patient management. A solid reaction strongly suggests a benign and slow-growing process that gives the bone enough time to wall off the lesion. Single lamellar reactions occur in acute and usually benign diseases. Multilamellar reactions are associated with intermediate aggressiveness and a growth rate close to the limit of the walling-off capabilities of the bone. Spiculated, interrupted, and complex combined reactions carry the worst prognosis, as they occur in the most aggressive and fast-growing diseases: the periosteum attempts to create new bone but is overwhelmed and may be breached.

We aimed to assess the impact of osteoid osteomas of the hip on the size and fatty infiltration of the muscle thigh in 42 patients. The thigh circumference, cross-sectional areas, and fatty atrophy of four anterior muscles were assessed on magnetic resonance axial T1-weighted images. A significant fatty atrophy was found in the studied muscles of the ipsilateral thigh except for the rectus femoris. No significant association was demonstrated with pain duration suggesting that muscle atrophy may rather be related to the locoregional inflammation than subsequent to the disuse of the limb., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Articular cartilage and subchondral bone are the key tissues in osteoarthritis (OA). The role of the cancellous bone increasingly attracts attention in OA research. Because of its fast adaptation to changes in the loading distribution across joints, its quantification is expected to improve the diagnosis and monitoring of OA. In this study, we simulated OA progression-related changes of trabecular structure in a series of digital bone models and then characterized the potential of texture parameters and bone mineral density (BMD) as surrogate measures to quantify trabecular bone structure. Five texture parameters were studied: entropy, global and local inhomogeneity, anisotropy and variogram slope. Their dependence on OA relevant structural changes was investigated for three spatial resolutions typically used in micro computed tomography (CT; 10 μm), high-resolution peripheral quantitative CT (HR-pQCT) (90 μm) and clinical whole-body CT equipment (250 μm). At all resolutions, OA-related changes in trabecular bone architecture can be quantified using a specific (resolution dependent) combination of three texture parameters. BMD alone is inadequate for this purpose but if available reduces the required texture parameter combination to anisotropy and global inhomogeneity. The results are summarized in a comprehensive analysis guide for the detection of structural changes in OA knees. In conclusion, texture parameters can be used to characterize trabecular bone architecture even at spatial resolutions below the dimensions of a single trabecula and are essential for a detailed classification of relevant OA changes that cannot be achieved with a measurement of BMD alone.

In the absence of obvious trauma, the calcifications/ossifications of the bone surface and soft tissues of the wrist, hand and fingers can be challenging and may not be noticed or lead to unnecessary examinations and monitoring. Although these are usually benign conditions and despite a favorable spontaneous outcome, surgical resection may be required and recurrence may occur. In practice, only paraneoplastic syndromes such as secondary hypertrophic osteoarthropathy (Pierre Marie-Bamberger syndrome) may reveal a malignant tumor, most often pulmonary. We suggest a diagnostic approach based on the initial clinical presentation (acute pain, chronic pain, growth±pain) and the radiological features., (Copyright © 2014 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Purpose: The radiologist plays a critical role at all steps of the management of patients with fibrous dysplasia (FD) and McCune-Albright syndrome (MAS). The development of a standardized approach to the management of FD/MAS is crucial given the low incidence and multiple clinical presentations of these conditions. Our aim was to develop recommendations for bone imaging in FD/MAS management., Materials and Methods: The establishment of National Reference Centers in France as part of a Health Ministry program for orphan diseases has triggered the development of recommendations for the clinical management of FD/MAS. We used a well-established robust methodological approach involving an extensive literature review by a multidisciplinary working group (20 healthcare professionals) and scoring by a peer-review group (20 healthcare professionals different from the 20 previous ones). There were four phases: a systematic literature review, drafting of initial recommendations, peer-review of this initial draft, and drafting of the final recommendations., Results: Fifty-seven specific recommendations are provided as key points for the diagnosis, prognosis, and follow-up of patients with FD/MAS. Issues of special interest are highlighted in the discussion, and areas in which future research is needed are identified., Conclusion: We believe the dissemination of these recommendations within the radiology community may facilitate communication between radiologists and other healthcare providers, thereby substantially improving the management of patients with these rare but potentially disabling conditions., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

A 40-year-old Mauritanian man consulted for back pain. A computed tomography of the spine showed patchy sclerosis of the fifth and seventh thoracic vertebral bodies with normal neural arch of T5 and sclerosis and hypertrophy of the neural arch of T7, as well as diffuse sclerosis of the T11 vertebral body with a normal neural arch. At MRI, low signal-intensity on T1-weighted images and high signal-intensity on T2-weighted images involved the whole T5 and T7 vertebrae and the vertebral body of T11. Working diagnoses included metastatic disease and lymphoma, and a biopsy of T7 and then T11 was carried out. Both showed pathological findings very suggestive of Paget's disease. Since CT is usually the more specific radiological examination in vertebral Paget's disease, we thought it could be useful to report this atypical CT presentation (patchy sclerosis of the vertebral body without diffuse bone texture changes and isolated involvement of the vertebral body) of vertebral Paget's disease.

Objectives: To assess the diagnostic value of clinical tests for degenerative rotator cuff disease (DRCD) in medical practice., Methods: Patients with DRCD were prospectively included. Eleven clinical tests of the rotator cuff have been done. One radiologist performed ultrasonography (US) of the shoulder. Results of US were expressed as normal tendon, tendinopathy or full-thickness tear (the reference). For each clinical test and each US criteria, sensitivity, specificity, negative predictive value and positive predictive value, accuracy, negative likelihood ratio (NLR) and positive likelihood ratio (PLR) were calculated. Clinical relevance was defined as PLR ≥2 and NLR ≤0.5., Results: For 35 patients (39 shoulders), Jobe (PLR: 2.08, NLR: 0.31) and full-can (2, 0.5) test results were relevant for diagnosis of supraspinatus tears and resisted lateral rotation (2.42, 0.5) for infraspinatus tears, with weakness as response criteria. The lift-off test (8.50, 0.27) was relevant for subscapularis tears with lag sign as response criteria. Yergason's test (3.7, 0.41) was relevant for tendinopathy of the long head of the biceps with pain as a response criterion. There was no relevant clinical test for diagnosis of tendinopathy of supraspinatus, infraspinatus or subscapularis., Conclusions: Five of 11 clinical tests were relevant for degenerative rotator cuff disease., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

High resolution-peripheral quantitative computed tomography (HR-pQCT) measurements are carried out in clinical research protocols to analyze cortical bone. Micro-computed tomography (micro-CT) is a standard tool for ex vivo examination of bone in 3D. The aim of this work was to evaluate cortical measurements derived from HR-pQCT images compared to those from synchrotron radiation (SR) micro-CT in a distal position (4.2 cm from the distal pilon). Twenty-nine tibia specimens were scanned with HR-pQCT using protocols provided by the manufacturer. The standard measured outcomes included volumetric bone density (gHA/cm(3)) of the cortical region (Dcomp), and the cortical thickness (Ct.Th, mm). New features, such as cortical porosity (Ct.Po) and mean pore diameter (Ct.Po.Dm), were measured by an auto-contouring process. All tibias were harvested from the posterior region and imaged with SR micro-CT (voxel size=7.5 μm). The cortical thickness, (Ct.Thmicro-CT), porosity (PoV/TV), pore diameter, pore spacing, pore number, and degree of mineralization of bone (DMB) were obtained for SR micro-CT images. For standard measurements on HR-pQCT images, site matched analyses with micro-CT were completed to obtain Dcomplocal and Ct.Thlocal. Dcomp was highly correlated to PoV/TV (r=-0.84, p<10(-4)) but not to DMB. Dcomplocal was correlated to PoV/TV (r=-0.72, p<10(-4)) and to DMB (r=0.40, p>0.05). Ct.Thlocal and Ct.Thmicro-CT were moderately correlated (r=0.53, p<0.01). Ct.Th and Ct.Po results from the autocontouring process are influenced by the level of trabecularization of the cortical bone and need manual correction of the endosteal contour. Distal tibia is a reliable region to study cortical bone with Dcomp as the best parameter because it reflects both the micro-porosity (Havers canals) and macro-porosity (resorption lacunae) of the cortical bone., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: The objective of this study was to report 11 cases of malignant head and neck paraganglioma and to compare their epidemiological, clinical, and genetic characteristics, their natural history and their treatment with those of a series of 131 benign paragangliomas., Patients and Methods: Retrospective analysis of 142 patients with head and neck paraganglioma managed between 2001 and 2008. Age at the time of diagnosis, gender, primary tumour site, presence of other non-head/neck paragangliomas and/or metastases diagnosed by imaging (CT, MRI, Octreoscan or (18)F-FDG PET), histology, urinary catecholamine and metanephrine levels, family history, and genetic test results were recorded., Results: This series comprised 131 benign head and neck paragangliomas, mostly observed in women with a mean age at diagnosis of 45 years and a predominance of tympanojugular sites (followed by carotid and vagal sites) with 5% of secreting tumours and 20% of multifocal tumours. Eleven patients (7.7%) with a 1:1 sex ratio presented criteria of malignancy. These patients, with a lower mean age (38 years), predominantly presented carotid lesions with a higher rate of secreting and multifocal tumours, 27% and 46% respectively. The main sites of metastases were bone and lymph nodes. No tympanic paragangliomas were observed., Conclusions: Malignant paragangliomas are mainly observed in young patients with multifocal tumours, particularly carotid tumours, and are predominantly related to subunit SDH-B mutation. The work-up in these high-risk patients must include whole body scintigraphy and spine MRI. Malignancy is not necessarily associated with a poor short-term prognosis due to the slow course of the disease., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Purpose: To assess the morphologic changes of osteoid osteomas on computed tomographic (CT) scans in association with pain duration., Materials and Methods: Institutional review board approval was obtained. Informed consent was waived. From January 2008 to December 2012, 235 patients were treated with interstitial laser ablation at the Hôpital Lariboisière. Ninety-six patients with histopathologically proven osteoid osteomas, complete clinical files, and CT data were studied retrospectively. The following variables were assessed: age, sex, bone location, bone segment, location of the osteoid osteoma in relation to the native cortex, nidus area, nidus calcification area and attenuation at CT, and nidus mineralization ratio (percentage of the calcification area over the total nidus area). Analysis of variance, Kaplan-Meier method, and Cox multivariate regression model were used for statistical analyses., Results: The study sample consisted of 96 patients, 68 of whom were male (71%) and 28 of whom were female (29%) (ratio of male to female patients, 2.4:1). Mean age ± standard deviation was 22.2 years ± 10.4 (range, 4-54 years; median, 18.5 years). The patients' age and nidus mineralization ratio increased significantly with pain duration (hazard ratio, 0.975 [P = .031] and 0.193 [P = .007], respectively). No significant association was found between pain duration and other variables, including the nidus area. In long bones, diaphyseal osteoid osteomas were significantly less mineralized than those in other locations (P = .009)., Conclusion: The nidus mineralization ratio of osteoid osteomas increases significantly with pain duration and may be a marker of tumor age. Diaphyseal osteoid osteomas demonstrate a lower ratio of nidus mineralization. At the onset of symptoms, older patients experience pain for a longer period before treatment.

Objective: To assess the correlation of T2 mapping abnormalities to knee pain location, in young adults with normal standard knee MRI at 3.0 Tesla., Subjects and Methods: Twenty-three consecutive patients were included prospectively from September 2011 to April 2012. Inclusion criteria were age under 50 years old, knee pain without surgical history, and normal knee MRI at 3.0 Tesla (sagittal T1-weighted images, and sagittal, axial and coronal proton-density-weighted images with saturation of fat signal). Ten asymptomatic volunteers were also included as a control group. Patients and controls had a cartilage T2 mapping MRI sequence in addition to the standard MRI protocol. Two musculoskeletal radiologists, blinded to the patient/control condition and pain location, independently reviewed the T2 mapping images. T2 values below 40 ms were considered normal. They rated the number of hyaline cartilage lesions and their grade according to an ICRS-like score (inspired by the International Cartilage Research Society score) in each anatomical compartment (medial and lateral femoro-tibial and anterior patello-femoral joints). In addition, the T2 value of the largest lesion was measured. Patient's pain location was classified in the following categories: anterior, lateral, medial and global. T2 mapping findings were compared to pain location, and retrospectively to the initial standard sequences. Sensitivity and specificity were calculated for MRI with T2 mapping according to pain location for each reader. Kappa coefficient was calculated for inter-reader agreement. We used variance analysis in a linear regression to compare T2 values and ICRS-like classification in each compartment., Results: Sensitivity of MRI with T2 mapping, according to the symptomatic compartment, was respectively: 78% and 87% for Reader 1 and Reader 2 and specificity was 70% for both readers. Kappa coefficient for T2 mapping abnormalities location and pain location was good, with a calculated value of 0.64. There was no significant correlation between ICRS-like classification and T2 values of lesions (p = 0.18)., Conclusion: Our results suggest that T2 mapping is an interesting MRI sequence for the exploration of young patients knee pain in case of normal MRI with a standard protocol, with a good correlation between pain location and focal prolongations of the cartilage T2 relaxation time.

The quantification of changes in the trabecular bone structure induced by musculoskeletal diseases like osteoarthritis, osteoporosis, rheumatoid arthritis, and others by means of a texture analysis is a valuable tool which is expected to improve the diagnosis and monitoring of a disease. The reaction of texture parameters on different alterations in the architecture of the fine trabecular network and inherent imaging factors such as spatial resolution or image noise has to be understood in detail to ensure an accurate and reliable determination of the current bone state. Therefore, a digital model for the quantitative analysis of cancellous bone structures was developed. Five parameters were used for texture analysis: entropy, global and local inhomogeneity, local anisotropy, and variogram slope. Various generic structural changes of cancellous bone were simulated for different spatial resolutions. Additionally, the dependence of the texture parameters on tissue mineralization and noise was investigated. The present work explains changes in texture parameter outcomes based on structural changes originating from structure modifications and reveals that a texture analysis could provide useful information for a trabecular bone analysis even at resolutions below the dimensions of single trabeculae.

Tibial hyperostosis may be encountered in musculoskeletal imaging, incidentally or during the investigation of a leg pain. Hyperostosis involves the exuberant production of osseous tissue and results in cortical, periosteal and/or endosteal thickening of the bone. As a long bone with thick cortices, the tibia has a significant probability of being affected by ubiquitous bone diseases. As a tubular long bone, the tibia is likely to be involved in extensive infectious conditions such as osteomyelitis. As a bone of the lower limb, the tibia undergoes high stresses and may be affected by decrease in bone strength or repetitive submaximal stress. The tibia is also particularly involved in some bone sclerosing dysplasias and Paget's disease. In this work, we aim at highlighting the main conditions leading to tibial hyperostosis and try to provide key elements to narrow down the several diagnostic possibilities. Osteoid osteomas, fatigue or insufficiency fractures, infectious conditions, vascular lesions, sclerosing bone dysplasias and Paget's disease represent the main challenging diagnoses to discuss., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Knee osteoarthritis is associated with structural changes in the joint. Despite its many drawbacks, radiography is the current standard for evaluating joint structure in trials of potential disease-modifying osteoarthritis drugs. MRI is a non-invasive alternative that provides comprehensive imaging of the whole joint. Frequently used MRI measurements in knee osteoarthritis are cartilage volume and thickness; others include synovitis, synovial fluid effusions, bone marrow lesions (BML) and meniscal damage. Joint replacement is considered a clinically relevant outcome in knee osteoarthritis; however, its utility in clinical trials is limited. An alternative is virtual knee replacement on the basis of symptoms and structural damage. MRI may prove to be a good alternative to radiography in definitions of knee replacement. One of the MRI parameters that predicts knee replacement is medial compartment cartilage volume/thickness, which correlates with radiographic joint space width, is sensitive to change, and predicts outcomes in a continuous manner. Other MRI parameters include BML and meniscal lesions. MRI appears to be a viable alternative to radiography for the evaluation of structural changes in knee osteoarthritis and prediction of joint replacement.

Intratendinous ganglia are rare. We report the case of a sedentary woman with chronic mechanical anterolateral pain of the knee and an extensive ganglion of the patellar tendon as indicated on magnetic resonance (MR) and ultrasound (US) examinations. There was evidence of a high-riding patella, patellar malalignment and patellar tendon-lateral femoral condyle friction syndrome with significantly close contact between the patellar tendon and the lateral facet of the femoral trochlea. The ultrasound-guided aspiration of the ganglion enabled a localized injection of an anti-inflammatory drug (cortivazol) and the cytopathological examination of the fluid, which confirmed the diagnosis. Clinical improvement was maintained with knee rehabilitation and was satisfactory at follow-up after 1 year. To our knowledge, we report the first case of a ganglion of the patellar tendon subsequent to patellar tendon-lateral femoral condyle friction syndrome. We found that this case was illustrative of mucoid degeneration in connective tissue due to chronic repetitive microtraumas. Additionally, this case provided the opportunity to discuss the management of this condition in a sedentary individual with a high-riding patella and patellar malalignment.

Objective: Bone marrow lesions (BMLs) in the knee are associated with pain and compartment-specific joint space narrowing. However, the correlation of BMLs with bone mineral density (BMD) has rarely been investigated. The aim of the present study was to examine whether BMD in BMLs is altered compared to the surrounding bone., Design: Thirty-four BMLs detected in osteoarthritis (OA) knees (KL grade 2 and 3) of 26 patients were investigated. A 3D-segmentation was used to determine BML volumes of interest (VOI) and their surrounding bone in MR images. These VOIs were registered to corresponding single-energy QCT images and a BMD analysis was performed. The same VOIs were transferred to control datasets (19 OA patients without BMLs) by an elastic registration, where the BMD analysis was repeated. To account for the dependence of bone marrow composition on BMD measures derived using single-energy QCT, simulations were performed to evaluate how changing fat-water compositions likely occurring with BML development may influence BMD measures and observed BMD differences between patients with and without BMLs. The association between loading in the knee and the occurrence of BMLs was investigated by medial to lateral (M:L) BMD ratios., Results: BMD was significantly increased at BML locations, even with a fat-to-water conversion rate of 39%. The M:L BMD ratio was significantly increased in bones with medial BMLs., Conclusions: BMD was examined exactly at BML locations and surrounding bone using highly accurate segmentation and registration methods. BMD was significantly increased at BML locations (P < 0.05)., (Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

We report the case of a 42-year-old man with histologically proven plantar fibromatosis (Ledderhose disease) demonstrating an uncommon brain gyriform pattern at MRI, so far exclusively described in the low-grade fibromyxoid sarcoma (LGFMS). An acoustic posterior enhancement at ultrasound, a high intensity on T2w and post-contrast T1wMR images were unusual and related to a high tumor cellularity at histology with no myxoid tissue. The juxtaposition of areas of high and low cellularity (with more fibrous material) in a multilobulated mass built a brain gyriform pattern at MR, similar to what was so far described exclusively in LGFMS. This case demonstrates that the brain gyriform pattern may also be observed in other soft tissue fibrous tumors with no myxoid material but with high cellularity areas alternating with fibrous zones of low cellularity., (Copyright © 2012 Elsevier Ltd. All rights reserved.)