Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

Objectives: The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Methods: Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. Results: The radiation dose of ULD-CT was 0.16 ± 0.006mSv compared with 11.2 ± 2.7mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Conclusion: Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. Key Points : • Radiation dose is a key concern with the increased use of thoracic CT • Ultra-low-dose chest CT approximates the radiation dose of conventional chest radiography • Ultra-low-dose chest CT can be of diagnostic quality • Solid pulmonary nodules are clearly depicted on ultra-low-dose chest C

Update In Musculoskeletal Imaging: From Diagnosis To Treatment

Medical imaging plays an important role in care of patients with musculoskeletal pathologies. In this field, all Imaging modalities are useful, providing morphological and functional information. The presence of metallic implants and the complexity of structures require an update of imaging techniques to better understand the structural static data. Finally, imaging- guided treatment of bone and soft tissue diseases has benefited from the developing techniques to achieve an optimal target with minor adverse effects. This thesis describes the evolution in this direction in selected fields of musculoskeletal imaging

Réduction d'artefacts métalliques des matériaux d'ostéosynthèse au scanner: méthodes et algorithmes de reconstructions

Le scanner est l'examen de choix pour évaluer l'os et le matériel d'ostéosynthèse à la recherche des complications. Cette imagerie présente toujours un challenge malgré le développement des détecteurs. Les artéfacts de durcissement, l'appauvrissement en flux des photons et d'autres types d'artéfacts dégradent la qualité de l'image. Plusieurs méthodes permettent la réduction d'artefacts mais elles augmentent la dose d'irradiation. Récemment l'application de l'imagerie virtuelle monochromatique a permis l'amélioration des artéfacts de durcissement, mais elle a aussi engendré la diminution de la résolution en contraste, d'où le développement des algorithmes de réduction d'artéfacts dédiés permettant une bonne analyse de ces tissus. Ces algorithmes permettent la segmentation des images reconstruites selon leurs nombres HU et la création des images corrigées depuis l'image d'origine. Ces algorithmes sont largement rapportés et prouvés efficaces dans de multiples publications. Ce travail illustre un exemple de ces algorithmes et son efficacité dans l'amélioration de la qualité d'images

Tumeur à cellules géantes de l’os

Giant cell tumor is a benign epiphyseo-metaphyseal bone tumor affecting the young patient. It is characterized by an extensive osteolysis, a high potential for recurrence, a risk of malignant transformation and pulmonary metastases. Curettage and cavity filling is the most common treatment, even in the case of a pathological fracture. A wide resection with prosthetic reconstruction must sometimes be considered. Better knowledge of the role of RANK-L in the pathophysiology of these tumors has led to clinical trials involving denosumab. Treatment with denosumab is suggested for inoperable lesions, or for aggressive lesions, in particular of the spine, pelvis, and sacrum before en bloc resection.La tumeur à cellules géantes est une tumeur osseuse bénigne épiphysométaphysaire touchant le sujet jeune. Elle est caractérisée par une ostéolyse parfois extensive, un potentiel de récidive élevé, un risque de transformation maligne et de métastases pulmonaires. Le curetage-comblement est le traitement de choix, y compris en cas de fracture pathologique. Une résection plus large avec reconstruction prothétique doit parfois être envisagée. La meilleure connaissance du rôle de RANK-L dans la physiopathologie de ces tumeurs a conduit à des essais cliniques impliquant le dénosumab. Un traitement par celui-ci est proposé pour les lésions inopérables ou agressives, notamment du rachis, du pelvis et du sacrum, avant une résection en bloc

Tumeurs cartilagineuses

Les tumeurs cartilagineuses sont des pathologies rares, dont la découverte est souvent fortuite sur une imagerie réalisée pour une autre raison. Parfois symptomatiques (douleur, raideur articulaire, déformation, fracture), elles doivent motiver une exploration clinique, radiologique, et histopathologique. La prise en charge dépend des lésions identifiées et peut comporter un simple suivi clinique ou un geste chirurgical complexe, fruit d'une discussion menée par une équipe multidisciplinaire composée de radiologues, pathologues et chirurgiens. La découverte d'une lésion cartilagineuse induit souvent une dose d'inquiétude non négligeable chez les patients atteints. Leur connaissance, par le médecin traitant et le chirurgien orthopédiste, nous semble indispensable afin de proposer une prise en charge optimale qui devra se faire dans un centre spécialisé

Forensic age estimation at the University Center of Legal Medicine Lausanne-Geneva: a retrospective study over 12 years.

With the undeniable increase in asylum requests from unaccompanied alleged minors, age estimation of living individuals has become an essential part of the routine work in European forensic centers. This study aims to review the forensic age estimations performed in our center since 2010, to evaluate the state-of-the-art of this practice in Switzerland with the evolution of the methodology according to upcoming recommendations. Our institute's expert reports performed between 2010 and 2022 were retrospectively analyzed. We gathered the following parameters: demographic data, morphological characteristics, alleged age compared with the assessed minimum age, sexual maturation, dental and bone age. When available, we collected personal and family history, medical history, records of torture-related/self-inflicted injuries, and information about eating habits that might affect skeletal development. Data collection amounted to 656 cases. Forensic age estimations ordered by the Swiss Secretariat for Migration (SEM) represented 76.4% of cases, with 23.6% of them ordered by the Court/Public Prosecutor. Most alleged minors were male (94.5%) and came from Afghanistan (53.4%). Adjunction of CT scans of the sternoclavicular joints was necessary in 86.4% of cases. Only 25.2% of our reports concluded on most probable minority, with 55.6% of definite majors; in 19.2% of our cases, minority could not be excluded. This study aspires to further broaden our expertise regarding forensic age estimations. Given the increasing migratory flows, we can expect a notable increase in the frequency of these requests. Consequently, this study aims to promote a multidisciplinary approach and the international standardization of the methodology of these estimations

Spinal uptake mimicking metastasis in SPECT/CT bone scan in a patient with superior vena cava obstruction

A 46-year-old female patient with a mediastinal neuroendocrine carcinoma complicated by superior vena cava syndrome was referred for a bone metastatic workup. Bone scan with SPECT/CT showed several vertebral fixations without alterations on the unenhanced CT, but a CT scan with injection of contrast media showed vertebral densities matched to the lesions described on the SPECT/CT. This pattern confirmed presence of collateral paths through vertebral veins due to superior vena cava syndrome. Lack of metastases was confirmed by MRI

Radiological assessment of irreducible posterolateral knee subluxation after dislocation due to interposition of the vastus medialis: a case report

Knee dislocation is a serious and relatively uncommon traumatism that every emergency room is supposed to diagnose and treat rapidly. Most of the time these dislocations reduce spontaneously or with closed reduction. If a subluxation persists, an incarceration of soft tissue in the joint must be suspected. Irreducible knee subluxations after dislocation are rare entities better described in the orthopaedic than in the radiological literature. However, the initial radiological assessment is an important tool to obtain the correct diagnosis, to detect neurovascular complications, and to plan the most suitable treatment. In cases of delayed diagnosis, the functional prognosis of the joint and even the limb may be seriously compromised primarily because of vascular lesions. Thereby, vascular imaging is essential in cases of dislocation of the knee, and we will discuss the role of angiography and the more recent use of computed tomography angiography or magnetic resonance angiography. Our patient presented with an irreducible knee subluxation due to interposition of the vastus medialis, and we will review the classical clinical presentation and 'do not miss' imaging findings on conventional radiography, computed tomography angiography, and magnetic resonance imaging. Finally, we will also report the classical imaging pathway indicated in knee dislocation, with a special emphasis on the irreducible form