Papers by Jean-Denis Laredo
Journal of Bone and Joint Surgery, 2011
Background: Despite the importance of the hip muscles in protecting against hip fracture and in t... more Background: Despite the importance of the hip muscles in protecting against hip fracture and in the outcome of hip arthroplasty, the variability in their fat content has not been previously studied. Our objectives were to evaluate the variability in the fat content of the hip muscles in a population without myopathy or a need for hip surgery with the use of computed tomography (CT), to study the relationship between hip muscle fat content and physical performance, and to identify medical conditions and lifestyle habits associated with an increase in hip muscle fat content. Methods: Ten normal subjects without a relevant medical history and ninety-nine consecutive nonsurgical patients without myopathy (age, twenty-one to ninety-four years) underwent a nonenhanced CT scan of the pelvis. Patients were asked to perform physical tests (six-meter walk, repeated chair stands, and Trendelenburg test), and their level of physical activity and medical history were recorded. Evaluation of the fat content of the hip muscles was based on the analysis of four reproducible and representative CT slices with use of custom software. Results: The fat content varied among the muscles, with an anteroposterior gradient from the hip flexors (mean, 2%) to the hip extensors (mean, 10%). This gradient increased after fifty years of age. Fat content also varied considerably among patients. Higher fat content was associated with poorer performance on physical tests, even after adjustment for the cross-sectional area of the muscle (p < 0.05). Higher fat content was also associated with greater age, higher body-mass index, and lower physical activity (p < 0.001). Conclusions: The observed variability in the fat content of individuals without myopathy or a need for hip surgery should be useful for comparison with future studies of specific populations of patients, such as those with muscle weakness secondary to hip fracture or hip surgery. Simple lifestyle changes such as dietary restriction, increased physical activity, and vitamin D supplementation may decrease muscle fat content and improve physical performance in the elderly.
IRBM, 2009
Muscle volume is an essential parameter in clinical evaluation and in biomechanical model develop... more Muscle volume is an essential parameter in clinical evaluation and in biomechanical model development. Nevertheless, the difficulty in volumic muscle reconstruction from medical images is the noise they contain that limits the efficiency of image processing to automatically segment muscle. This study was conducted to explore hip muscle volume from CT-scan acquisition and to analyze the variability of muscle volume for a population of 98 subjects with age ranged from 21 to 94 years. To obtain three-dimensional muscle reconstruction, a method based on a deformation of a parametric specific object generated from a reduced number of muscle contours was used. A reproducibility study was conducted for muscle volume estimation. Coefficient of variation was found less than 8.9% and intraclass correlation coefficients were greater than 0.88. Results showed no significant difference between left and right muscles for this population. After adjustment to age and body mass index, hip muscle volumes were significantly different between men and women. This muscle volume reconstruction method allowed quantifying muscle volume distribution within a large population.
Molecular Genetics and Metabolism, 2015
ABSTRACT To study the long-term evolution of the bone marrow burden (BMB) score at MRI in patient... more ABSTRACT 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). 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. 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. 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. • 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.
European Radiology, 2015
Purpose To investigate the efficacy of percutaneous chemonucleolysis using ethanol gel (PCEG) in ... more 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.
European radiology, Jan 16, 2015
To study the long-term evolution of the bone marrow burden (BMB) score at MRI in patients with Ga... more 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). 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. 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. In Gaucher patients, the trend of MRI BMB score...
Clinical imaging
We aimed to assess the impact of osteoid osteomas of the hip on the size and fatty infiltration o... more 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.
Journal de radiologie, 2003
Three different techniques will be discussed. The first procedure is the biopsy of the lumbar ver... more Three different techniques will be discussed. The first procedure is the biopsy of the lumbar vertebra or lumbar intervertebral disc for patients with tumors or infections of the lumbar spine. The different needles that can be used in function of consistency and location of the lesion will be shown. The transpedicular and posterolateral techniques will be described. Cementoplasty for tumors and selected patients with osteoporotic vertebral collapse generates much interest. The transpedicular and posterolateral techniques will be described. Indications and complications, more frequent in patients with tumors, will be reviewed. Finally, foraminal injections of steroids in patients with radicular symptoms secondary to degenerative change will be discussed. Techniques for needle placement will be reviewed. Results from these injections will also be reviewed.
The Foot, 2013
We report the case of a 42-year-old man with histologically proven plantar fibromatosis (Ledderho... more 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.
BoneKEy reports, 2014
Articular cartilage and subchondral bone are the key tissues in osteoarthritis (OA). The role of ... more 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-rel...
Revue du Rhumatisme Monographies, 2014
r é s u m é L'infection ostéo-articulaire est une infection sévère, tout particulièrement lorsqu'... more r é s u m é L'infection ostéo-articulaire est une infection sévère, tout particulièrement lorsqu'elle intéresse le rachis. Elle est protéiforme : spondylodiscite, spondylite, arthrites zygapophysaires et abcès épiduraux. Elle justifie toujours une prise en charge diagnostique et thérapeutique rapide, parfois urgente. Elle touche avec prédilection le sujet de plus de 70 ans. Un terrain fragilisé, une mauvaise tolérance clinique générale, la présence de signes neurologiques, la localisation au rachis cervical sont des facteurs de gravité. L'imagerie a pour objectifs de faire le diagnostic positif de l'infection du rachis, de préciser l'extension discale, vertébrale, paraspinale et épidurale, d'évaluer les répercussions méningées et radiculo-médullaires et d'aider à l'isolement de l'agent pathogène grâce à une biopsie percutanée. L'identification du germe est accélérée par les nouvelles techniques comme la spectroscopie de masse. Les agents pathogènes les plus fréquents sont le staphylocoque doré, les streptocoques, les mycobactéries du groupe tuberculosis.
PET Clinics, 2008
Imaging plays a major role in the diagnosis and management of musculoskeletal disorders. Conventi... more Imaging plays a major role in the diagnosis and management of musculoskeletal disorders. Conventional imaging methods, including plain film radiography, CT, and MR imaging, provide high-resolution structural information. These modalities are somewhat insensitive, however, for detecting early disease and often fail to distinguish between active and inactive lesions related to prior disease. Early diagnosis or exclusion of infection and inflammation are crucial for optimal management of patients. PET is an imaging technique that provides functional information through the distribution and uptake of positron-emitting radiotracers. Two commonly used radiotracers for PET imaging of musculoskeletal disorders are F18-fluorodeoxyglucose (FDG) and 18 F-sodium fluoride (18 F-NaF); the former is most commonly used in clinical practice. 18 F-NaF has great promise, however, and likely will replace conventional technetium-based compounds. FDG originally was used to image brain function in healthy and disease states. With the advent of whole-body imaging techniques in the latter half of the 1980s, it became apparent that glucose metabolism also was elevated in malignancies and in infectious and noninfectious inflammatory processes. 18 F-NaF previously was used widely for skeletal imaging after its introduction in the 1960s and subsequent FDA approval in 1972 1
Revue du Rhumatisme, 2005
Objectifs.-Montrer que l'arthroscanner hélicoïdal avec reconstructions multiplanaires met en évid... more Objectifs.-Montrer que l'arthroscanner hélicoïdal avec reconstructions multiplanaires met en évidence des atteintes cartilagineuses et analyser les caractéristiques de celles-ci, chez des patients suspects de coxarthrose et dont les radiographies étaient normales ou non probantes. Méthodes.-Nous avons réalisé une étude rétrospective des arthroscanners de hanches pathologiques de patients présentant une douleur de hanche d'horaire mécanique et des radiographies normales de face et en faux profil de Lequesne. Ces arthroscanners étaient réalisés en coupes axiales natives millimétriques avec des reconstructions millimétriques dans les plans coronal et sagittal. Les radiographies et arthrographies ont été lues de manière consensuelle et les arthroscanners lus séparément puis en consensus par deux radiologues expérimentés. Résultats.-Dix-huit patients ayant un dossier radiologique complet et présentant des anomalies sur l'arthroscanner ont été retenus pour l'étude ; l'âge moyen était de 47,8 ans, le sex-ratio de 14 femmes pour quatre hommes. Nous avons observé que l'atteinte cartilagineuse, souvent profonde, touchait l'acétabulum chez tous nos patients, plus précisément en région antérosupérieure. Dans 67 % des cas coexistait une fissure du bourrelet acétabulaire. Les reconstructions faites dans les plans sagittal et coronal étaient plus informatives que les coupes axiales natives. La reproductibilité interobservateurs était très bonne pour le diagnostic des atteintes cartilagineuses en arthroscanner. Conclusions.-Dans la hanche douloureuse à radiographies normales, l'arthroscanner hélicoïdal permet de porter un diagnostic de coxarthrose en montrant des lésions cartilagineuses situées le plus souvent à la partie antérosupérieure de l'acétabulum.
Joint Bone Spine, 2015
Vertebral Paget's disease produces a large panel of radiologic appearances sometimes atypical and... more Vertebral Paget's disease produces a large panel of radiologic appearances sometimes atypical and pseudotumoral. Classical classifications of bone alterations based on pathophysiological hypotheses do not always match the imaging findings. This article will review the computed tomography (CT) and magnetic resonance imaging (MRI) features of Paget's disease of the spine with special emphasis on morphological findings that differentiate Paget's disease from tumors. Combined CT and MRI analyses usually provide the diagnosis of Paget's disease.
Seminars in Musculoskeletal Radiology, 1997
Lumbar chemonucleolysis is an alternative treatment of the sciatic pain due to a disc herniation.... more Lumbar chemonucleolysis is an alternative treatment of the sciatic pain due to a disc herniation. It gives good results in 70 to 80% of selected patients. When a correct technique is used, the complication rate is lesser than that of the open surgery. The indications of lumbar chemonucleolysis are larger than in the past and include lateral disc herniations, large or migrated disc herniations, and patients under 18 years or over 60 years. Further studies are necessary to determine if magnetic resonance imaging helps in patients selection and improve the success rate of chemonucleolysis.
Seminars in Musculoskeletal Radiology, 1997
Distension arthrography under fluoroscopic control may be useful in frozen shoulder syndrome. The... more Distension arthrography under fluoroscopic control may be useful in frozen shoulder syndrome. The technique consists of an intra-articular injection of 2 to 3 mL of contrast material, 3 mL of 2% lidocaine, 1.5 mL of cortivazol, and distension of the joint capsule with 30 to 40 mL of refrigerated sterile saline solution. This injection is immediately followed by a physiotherapy program. The authors report their experience of distension arthography in 30 shoulders. Results were good to very good in 90% of cases at 40-day follow-up. No recurrence of a frozen shoulder syndrome was observed and no complications were encountered in this series.
Skeletal Radiology, 2000
The most serious complication of Paget's disease is sarcomatous degeneration of pagetic bone. Mul... more The most serious complication of Paget's disease is sarcomatous degeneration of pagetic bone. Multifocal sarcomatous degeneration occurs mainly in polyostotic Paget's disease. Multifocal Paget's sarcoma is uncommon and can arise in any site. We report two cases of synchronous multifocal sarcomatous degeneration. The two patients were elderly women (aged 77 and 86 years, respectively) who developed sarcomatous lesions concomitantly, in the first case report in left ilium, left tibia, and first lumbar vertebra and in the second case report in the skull, right ilium, and sacrum. Whether these cases are due to the simultaneous development of several primaries or to metastases from a single primary remains unclear.
Skeletal Radiology, 2014
A 40-year-old Mauritanian man consulted for back pain. A computed tomography of the spine showed ... more 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease. Since CT is usually the more specific radiological examination in vertebral Paget&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease.
Skeletal Radiology, 1986
This report concerns 12 patients, eight young adults and four adolescents, presenting with lumbar... more This report concerns 12 patients, eight young adults and four adolescents, presenting with lumbar or sciatic pain. This was associated with an unusual defect of the inferior and posterior edges of the vertebral bodies of L4 or L5, together with a small bony ridge protruding into the spinal canal. We found 11 similar cases in the literature, all involving adolescents except for one young adult. It has been considered to be the result of a fracture of the posterior ring apophysis in association with a herniated disc. In our cases, in the absence of any known previous trauma, the radiological features and surgical results and the similarity and frequent association with typical lesions of Scheuermann disease, all suggest a posterior marginal cartilaginous node. The inferior lumbar location and frequent association with herniated disc and sciatic nerve root compression in young patients are discussed.
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Papers by Jean-Denis Laredo