Repeatability of a protocol to evaluate the effect of storage on the mechanical properties of the kidney in-vitro

International audienceIn biomechanical testing protocols of soft tissue, specimens may have to undergo freezing or other conservation methods, which could affect their mechanical properties. In order to evaluate the effects of conservation techniques, an experimental protocol based on shear wave elastography - which provides an assessment of shear modulus (μ) was developed and applied to porcine kidneys. First, the organ is pinned onto a polystyrene plate. Then the plate then used to position the organ with respect to an ultrasound probe. This study provides an estimation of the repeatability of μ after repositioning a single kidney, and evaluates the effects of storing 8 fresh kidneys at room temperature for two days. μ were computed rectangular windows centred on the image and moving along the organ depth. When repositioning the organ, μ was more repeatable in the cortex near the capsule than in the central regions of the organ. These regions were also more inhomogeneous and imaging was not always possible due to ultrasound penetration issues. The cortex near the capsule was softer than the central regions including pyramids (e.g. 6.1±2.4kPa at 10% depth vs. 9.3±3.5kPa at 30% depth, n=8). Storage for two days had no significant effect on these values (p>0.25)

Morphometric analysis of tumor microvessels for detection of hepatocellular carcinoma using contrast-free ultrasound imaging: A feasibility study

IntroductionA contrast-free ultrasound microvasculature imaging technique was evaluated in this study to determine whether extracting morphological features of the vascular networks in hepatic lesions can be beneficial in differentiating benign and malignant tumors (hepatocellular carcinoma (HCC) in particular).MethodsA total of 29 lesions from 22 patients were included in this work. A post-processing algorithm consisting of clutter filtering, denoising, and vessel enhancement steps was implemented on ultrasound data to visualize microvessel structures. These structures were then further characterized and quantified through additional image processing. A total of nine morphological metrics were examined to compare different groups of lesions. A two-sided Wilcoxon rank sum test was used for statistical analysis.ResultsIn the malignant versus benign comparison, six of the metrics manifested statistical significance. Comparing only HCC cases with the benign, only three of the metrics were significantly different. No statistically significant distinction was observed between different malignancies (HCC versus cholangiocarcinoma and metastatic adenocarcinoma) for any of the metrics.DiscussionObtained results suggest that designing predictive models based on such morphological characteristics on a larger sample size may prove helpful in differentiating benign from malignant liver masses

Measuring the natural brain tissue pulsatility using ultrasound

Actuellement, l’étude du mouvement des tissus biologiques figure parmi les thématiques majeures dans le domaine de l’imagerie médicale, dont le challenge est d’apporter un complément d’information clinique et de permettre une aide au diagnostic. L’application récente de techniques d’élastographie ouvre de nouvelles perspectives de caractérisation biomécanique des tissus, et notamment du cerveau. Dans ce contexte, nous proposons une méthodologie innovante d’élastographie passive des propriétés mécaniques du tissu cérébral dont le but est de permettre à terme le diagnostic des maladies neurodégénératives.The study of biological tissues movement is currently, one of the major thematics in the medical imaging field. The challenge is to provide additional clinical information and allow for diagnostic assistance. The recently introduced elastographic techniques, provide ample opportunities for biomechanical tissues characterization, particularly of cerebral tissues. An innovative passive-elastographic methodology for assessing mechanical properties of brain tissue is proposed. The eventual aim is to allow for the diagnosis of neurodegenerative diseases

Ultrasonic elastography exploration of the foetal brain: A case of atypical choroid plexus papilloma

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First Evaluation of Zygomaticus Major Muscle Elastic Properties Using a US Elastography Technique

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Volumetric imaging and morphometric analysis of breast tumor angiogenesis using a new contrast-free ultrasound technique: a feasibility study

Abstract Background There is a strong correlation between the morphological features of new tumor vessels and malignancy. However, angiogenic heterogeneity necessitates 3D microvascular data of tumor microvessels for more reliable quantification. To provide more accurate information regarding vessel morphological features and improve breast lesion characterization, we introduced a quantitative 3D high-definition microvasculature imaging (q3D-HDMI) as a new easily applicable and robust tool to morphologically characterize microvasculature networks in breast tumors using a contrast-free ultrasound-based imaging approach. Methods In this prospective study, from January 2020 through December 2021, a newly developed q3D-HDMI technique was evaluated on participants with ultrasound-identified suspicious breast lesions recommended for core needle biopsy. The morphological features of breast tumor microvessels were extracted from the q3D-HDMI. Leave-one-out cross-validation (LOOCV) was applied to test the combined diagnostic performance of multiple morphological parameters of breast tumor microvessels. Receiver operating characteristic (ROC) curves were used to evaluate the prediction performance of the generated pooled model. Results Ninety-three participants (mean age 52 ± 17 years, 91 women) with 93 breast lesions were studied. The area under the ROC curve (AUC) generated with q3D-HDMI was 95.8% (95% CI 0.901–1.000), yielding a sensitivity of 91.7% and a specificity of 98.2%, that was significantly higher than the AUC generated with the q2D-HDMI (p = 0.02). When compared to q2D-HDMI, the tumor microvessel morphological parameters obtained from q3D-HDMI provides distinctive information that increases accuracy in differentiating breast tumors. Conclusions The proposed quantitative volumetric imaging technique augments conventional breast ultrasound evaluation by increasing specificity in differentiating malignant from benign breast masses

Propriétés élastiques du muscle zygomatique en utilisant la technique d'élastographie par ultrasons

International audienceL'expression du visage (mimique faciale) est animée par les mouvements des muscles peauciers (grand zygomatique, orbiculaires des lèvres, muscle abaisseur de l'angle de la bouche, etc…). Elle peut être altérée lors d'une paralysie faciale centrale ou le plus souvent périphérique qui peut être 1) a frigore (ou paralysie de Bell), la plus fréquente des paralysies faciales périphériques, 2) traumatique c'est-à-dire une lésion du nerf lors d'un accident, ou 3) due à une toute autre cause (tumorale, virale, ...). L'évaluation des déficits musculaires faciaux est subjective (palpation, vidéoscopie, etc …) et cette approche qualitative est insuffisante pour planifier les traitements, évaluer leur efficacité et suivre en rééducation fonctionnelle la récupération des patients traités. Ainsi, l'objectif principal de cette étude est d'utiliser notre savoir-faire en élastographie par résonance magnétique pour développer un protocole expérimental en imagerie ultrasonore (échographie) pour évaluer les propriétés fonctionnelles du zygomatique. Huit volontaires sains (4 femmes, 4 hommes, âge moyen : 25,3 ± 5,7 ans) sans lésion musculaire faciale ont été recrutés. Un test d'élastographie par ultrasons a été fait avec un échographe (Aixplorer) dont la spécificité est d'utiliser le mode d'imagerie breveté d'élastographie ShearWave (SWE) qui permet de cartographier et de quantifier en temps réel l'élasticité des tissus (kPa), indicateur important de modification tissulaire. Deux sondes échographiques (SLH20-6 : résolution 38 µm et SL10-2 : résolution 50 µm) ont été utilisées pour analyser le muscle à différentes profondeur

Improved ultrasound attenuation measurement method for the non-invasive evaluation of hepatic steatosis using FibroScan ®

International audienceControlled Attenuation Parameter (CAP) is a measurement of ultrasound attenuation used to assess liver steatosis non-invasively. However, the standard method has some limitations. We aimed to assess the performance of a new CAP method by ex vivo and in vivo assessments. The major difference with the new method is that it uses ultrasound data continuously acquired during the imaging phase of the FibroScan examination. Seven reference tissue-mimicking phantoms were used to test the performances. In vivo performances were assessed on two cohorts (in total 195 patients) of patients using magnetic resonance imaging proton density fat fraction (MRI-PDF) as a reference. The precision of CAP was improved by more than 50% on tissue-mimicking phantoms and between 22% and 41% in the in vivo cohort studies. The agreement between both methods was excellent and the correlation between CAP and MRI-PDFF improved in both studies (0.71 to 0.74, 0.70 to 0.76). Using MRI-PDFF as a reference, the diagnostic performance of the new method was at least equal or superior (area under the receiver operating curve 0.889 to 0.900, 0.835 to 0.873). This study suggests that the new continuous CAP method can significantly improve the precision of CAP measurements ex vivo and in vivo

DataSheet_1_Morphometric analysis of tumor microvessels for detection of hepatocellular carcinoma using contrast-free ultrasound imaging: A feasibility study.docx

IntroductionA contrast-free ultrasound microvasculature imaging technique was evaluated in this study to determine whether extracting morphological features of the vascular networks in hepatic lesions can be beneficial in differentiating benign and malignant tumors (hepatocellular carcinoma (HCC) in particular).MethodsA total of 29 lesions from 22 patients were included in this work. A post-processing algorithm consisting of clutter filtering, denoising, and vessel enhancement steps was implemented on ultrasound data to visualize microvessel structures. These structures were then further characterized and quantified through additional image processing. A total of nine morphological metrics were examined to compare different groups of lesions. A two-sided Wilcoxon rank sum test was used for statistical analysis.ResultsIn the malignant versus benign comparison, six of the metrics manifested statistical significance. Comparing only HCC cases with the benign, only three of the metrics were significantly different. No statistically significant distinction was observed between different malignancies (HCC versus cholangiocarcinoma and metastatic adenocarcinoma) for any of the metrics.DiscussionObtained results suggest that designing predictive models based on such morphological characteristics on a larger sample size may prove helpful in differentiating benign from malignant liver masses.</p

Development of a novel multiphysical approach for the characterization of mechanical properties of musculotendinous tissues

International audienceAt present, there is a lack of well-validated protocols that allow for the analysis of the mechanical properties of muscle and tendon tissues. Further, there are no reports regarding characterization of mouse skeletal muscle and tendon mechanical properties in vivo using elastography thereby limiting the ability to monitor changes in these tissues during disease progression or response to therapy. Therefore, we sought to develop novel protocols for the characterization of mechanical properties in musculotendinous tissues using atomic force microscopy (AFM) and ultrasound elastography. Given that TIEG1 knockout (KO) mice exhibit well characterized defects in the mechanical properties of skeletal muscle and tendon tissue, we have chosen to use this model system in the present study. Using TIEG1 knockout and wild-type mice, we have devised an AFM protocol that does not rely on the use of glue or chemical agents for muscle and tendon fiber immobilization during acquisition of transversal cartographies of elasticity and topography. Additionally, since AFM cannot be employed on live animals, we have also developed an ultrasound elastography protocol using a new linear transducer, SLH20-6 (resolution: 38 µm, footprint: 2.38 cm), to characterize the musculotendinous system in vivo. This protocol allows for the identification of changes in muscle and tendon elasticities. Such innovative technological approaches have no equivalent to date, promise to accelerate our understanding of musculotendinous mechanical properties and have numerous research and clinical applications