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CONTEXTE ET OBJECTIFS: L'élastographie transitionnelle (ET) ou Fibroscan® a été validée pour le diagnostic et la stadification de la fibrose hépatique dans l'hépatite C chronique, mais il manque un consensus clair sur les valeurs seuils optimales dans la maladie alcoolique du foie. Les objectifs de l'étude sont: (a) évaluer les seuils de la littérature et en déterminer de nouveaux pour le diagnostic de la fibrose chez les alcooliques; (b) investiguer l'impact de deux semaines d'abstinence sur les résultats de l'ET; (c) évaluer la précision de l'ET pour le diagnostic d'une hypertension portale significative; (d) évaluer la précision des tests sanguins non invasifs (APRI, Forns index, FIB-4); (e) étudier les facteurs histologiques (stéatose, hépatite alcoolique, fibrose perisinusoidale et biochimiques (transaminases et cholestase) confondants qui pourraient mener à une erreur de classification par ET.METHODES: Les patients admis pour désintoxication alcoolique ont été évalués par un premier Fibroscan®; si la valeur de l'ET était suggestive d'une fibrose significative (<: F2), une biopsie leur était proposée. Un second Fibroscan® a été proposé deux semaines plus tard à un sous-groupe de patients qui étaient restés abstinents. RESULTATS: 118 patients ont été inclus dans l'étude; 57 d'entre eux ont bénéficié d'un second Fibroscan®. Le Fibroscan® est bien corrélé avec l'histologie (p=0.680, p<0.01) et a une très bonne VPN de 92% pour exclure une fibrose sévère (<: F3) et de 93% pour une cirrhose (<: F4). Nos valeurs seuils optimales sont <:11.7 kPa pour F2, ;,15.2 pour F3 et<:21.2 pour F4. Après deux semaines d'abstinence, les mesures d'ET ont diminué en moyenne de 2.7 kPa (+/-0.9), ce qui a amélioré significativement la concordance entre le Fibroscan® et l'histologie. Le Fibroscan® et le gradient de pression hépatique veineuse (HVPG) sont aussi bien corrélés (p=O.753, p<0.01); une valeur d'ET <:30.6kPa pour prédire un HVPG <:1OmmHg a une spécificité de 94%. Le Fibroscan® a donné de meilleurs résultats que les tests sanguins non-invasifs. Aucun impact des facteurs confondants sur les erreurs de classification n'a été mis en évidence. CONCLUSION: Le Fibroscan® est actuellement la méthode non-invasive la plus précise pour diagnostiquer une fibrose chez les patients alcooliques. Une valeur d'ET inférieure à11.7 kPa permet d'exclure une fibrose significative et une valeur inférieure à 30.6 kPa des varices. Nous n'avons pas trouvé de facteurs expliquant la tendance du Fibroscan® à la surestimation par rapport à l'histologie, mais une période d'abstinence réduit cet effet. Les études à venir devraient se concentrer sur ce point. BACKGROUND AND OBJECTIVES: Transient elastography (TE) or Fibroscan® has been validated for the diagnosis and stadification of liver fibrosis in chronic hepatitis C, but there is no clear consensus on the optimal TE cut-off values in alcoholic liver disease (ALD). The objectives of the study are: (a)Io evaluate the literature Cut-offs and determine new ones for the diagnosis of fibrosis in alcoholic patients; (b) to investigate the impact of Iwo weeks of abstinence on TE results; (c) Io evaluate the diagnostic accuracy of TE for determining clinically significant portal hypertension; (d) Io evaluate the accuracy of non-invasive blood tests (APRI, Forns index, FIB-4); (e)Io study potential histological (steatosis, alcoholic hepatitis, perisinusoidal fibrosis) and biochemical (transaminases and cholestasis) confounding factors leading to misclassification by TE.METHODS: Patients admitted for alcohol withdrawal were evaluated by a first Fibroscan®; if the TE value was suggestive of significant fibrosis (;,, F2), they were proposed a liver biopsy. A second Fibroscan® was proposed two weeks later to a subgroup of patients who had remained abstinent.RESULTS: 118 patients were included in the study, among which 57 underwent a second Fibroscan®. Fibroscan® correlated well with the histological score (p=0.680, p<0.01) and showed a very good NPV, with a value of 92% for ruling out severe fibrosis (;,, F3) and 93% for cirrhosis (F4). Our optimal cut-offs were found al. 11.7 kPa for F2, ≥, 15.2 for F3 and ≥21.2 for F4. Alter two weeks of abstinence; there was a mean decrease of TE values of 2.7 kPa (+/-0.9) associated with a significantly better concordance between Fibroscan® and histology. Fibroscan® also correlated well with the hepatic venous pressure gradient (HVPG) (p=0.753, p<0.01); a TE value of 30.6 kPa for predicting an HVPG greater than 10mmHg yielded a 94% specificity. Fibroscan® performed better than all non-invasive blood tests. We could not find any impact of the confounding factors on misclassification. CONCLUSION: Fibroscan® is currently the most accurate non-invasive method for the diagnosis of fibrosis in patients with ALD. We can safely say that TE values below 11.7 kPa can rule out significant fibrosis and below 30.6 kPa varices. We did not find any factors which could explain the tendency of Fibroscan® to overestimate histological fibrosis, but a period of abstinence reduces this effect. Future studies should focus on this point.
Liver Diseases, Alcoholic --- Fibrosis --- Elasticity Imaging Techniques --- Hepatitis C
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Évaluation de la corrélation entre l'élasticité du cortex rénal mesurée par elastography point quantification ElastPQ et le score FIAT de fibrose rénale évalué par biopsie chez des patients atteints de néphropathie chronique. Méthode : 16 adultes atteints de néphropathie chronique et 16 volontaires sains ont eu un examen élastographique des reins par ElastPQ. Les mesures d'élasticité du cortex rénal étaient exprimées en kPa. 10 de ces 16 patients ont eu une biopsie dans le cadre de leurs soins pour laquelle le score FIAT a été évalué. L'existence potentielle d'une corrélation a été recherchée entre les mesures élastographiques et les paramètres biologiques, histologiques et échographiques dans le groupe malade. Une corrélation potentielle a été recherchée entre les valeurs élastographiques et les paramètres biologiques et échographiques dans le groupe des volontaires sains. Les données échographiques, élastographiques et biologiques des patients et des volontaires sains ont été comparées. Résultats : L'élasticité du cortex rénal n'était pas corrélée aux paramètres biologiques ou échographiques. Cependant, une corrélation significative a été observée entre l'élasticité du cortex rénal et le score FIAT (r = 0.7, p = 0.0282). Aucune différence significative des valeurs élastographiques n'a été trouvée entre le groupe contrôle et le groupe malade. Conclusion : L'élasticité du cortex rénal chez les patients atteints de néphropathie chronique était corrélée au score FIAT de la biopsie. Une différence significative entre les grades 1 et 2 du score FIAT avec une valeur seuil de 5.66kPa a été observée. Ce résultat offre des perspectives pour l'évaluation et la détection des néphropathies rénales chroniques avec la possibilité d'une réduction du nombre de biopsies rénales. Evaluation of the correlation between the renal cortex stiffness in chronic kidney disease (CKD) evaluated by elastography point quantification (ElastPQ) and the FIAT score of renal fibrosis in CKD. Methods 16 consecutive adults’ patients with CKD and sixteen healthy volunteers underwent ElastPQ elastography. The elastographic measurements of the renal cortex were expressed with kPa values. 10 patients with CKD had a clinically indicated biopsy for which interstitial fibrosis was evaluated by the FIAT score. Correlation: were evaluated between elasticity values and echographic, biological and histopathologic data for the patients comparison; echographic and biological results were used for the comparison of data between patients and volunteers. Results: Renal cortical stiffness did not correlate with any biological or echographic parameters, however, a significant correlation was observed between cortical stiffness and the FIAT score (r = 0.7, p = 0.0282). No significant differences were found between the renal cortical stiffness of the control group and de diseased group. Conclusions: Renal cortical stiffness in CKD by ElastPQ was correlated with the FIAT score. A significant difference was observed between the grade 1 and 2 of the FIAT score with a threshold of 5.66 kPa. This result offers perspectives in evaluation and detection of CKD with the possibility to reduce the number of biopsies.
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This comprehensive reference covers the principles and techniques used in performing breast elastography, an innovative imaging technology that can dramatically reduce the need for biopsies. The book begins with an introduction of the techniques, followed by sections on how to perform each technique and methods of interpretation, and concludes with more than 60 detailed case studies. Key Features: Includes case studies covering a wide range of breast pathologies and illustrating the use of all available elastography techniques to help radiologists obtain the best images for each pathologyCove
Breast Neoplasms --- Elasticity Imaging Techniques --- ultrasonography --- pathology --- Breast --- Breasts --- Chest --- Large-breasted women --- Tumors --- Ultrasonic imaging. --- Breast Neoplasms - ultrasonography --- Breast Neoplasms - pathology
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This book is the first to comprehensively explore elasticity imaging and examines recent, important developments in asymptotic imaging, modeling, and analysis of deterministic and stochastic elastic wave propagation phenomena. It derives the best possible functional images for small inclusions and cracks within the context of stability and resolution, and introduces a topological derivative-based imaging framework for detecting elastic inclusions in the time-harmonic regime. For imaging extended elastic inclusions, accurate optimal control methodologies are designed and the effects of uncertainties of the geometric or physical parameters on stability and resolution properties are evaluated. In particular, the book shows how localized damage to a mechanical structure affects its dynamic characteristics, and how measured eigenparameters are linked to elastic inclusion or crack location, orientation, and size. Demonstrating a novel method for identifying, locating, and estimating inclusions and cracks in elastic structures, the book opens possibilities for a mathematical and numerical framework for elasticity imaging of nanoparticles and cellular structures.
Elasticity --- Elastic properties --- Young's modulus --- Mathematical physics --- Matter --- Statics --- Rheology --- Strains and stresses --- Strength of materials --- Mathematics. --- Properties --- Dirichlet function. --- Helmholtz decomposition theorem. --- Helmholtz decomposition. --- HelmholtzЋirchhoff identities. --- Kelvin matrix. --- Kirchhoff migration. --- Lam system. --- MUSIC algorithm. --- Neumann boundary condition. --- anisotropic elasticity. --- asymptotic expansion. --- asymptotic formula. --- asymptotic imaging. --- ball. --- boundary displacement. --- boundary perturbation. --- boundary value problem. --- boundedness. --- cellular structure. --- compressional modulus. --- crack. --- density parameter. --- direct imaging. --- discrepancy function. --- displacement field. --- displacement. --- elastic coefficient. --- elastic equation. --- elastic inclusion. --- elastic moment tensor. --- elastic structure. --- elastic wave equation. --- elastic wave propagation. --- elastic wave. --- elasticity equation. --- elasticity imaging. --- elasticity. --- ellipse. --- energy functional. --- extended inclusion. --- extended source term. --- extended target. --- far-field measurement. --- filtered quadratic misfit. --- function space. --- gradient scheme. --- hard inclusion. --- hard inclusions. --- heterogeneous shear distribution. --- high contrast coefficient. --- hole. --- imaging functional. --- inclusion. --- incompressible limit. --- internal displacement measurement. --- layer potential. --- linear elasticity. --- linear transformation. --- linearized reconstruction problem. --- measurement noise. --- medium noise. --- nanoparticle. --- nonlinear optimization problem. --- nonlinear problem. --- operator-valued function. --- optimal control. --- potential energy functional. --- pressure. --- radiation condition. --- random fluctuation. --- resolution. --- reverse-time migration. --- scalar wave equation. --- search algorithm. --- shape change. --- shape deformation. --- shape. --- shear distribution. --- shear modulus. --- shear wave. --- small crack. --- small inclusion. --- small-volume expansion. --- small-volume inclusion. --- soft inclusion. --- stability analysis. --- stability. --- static regime. --- stochastic modeling. --- time-harmonic regime. --- time-reversal imaging. --- topological derivative. --- vibration testing.
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