Presentazione sul tema: "Elasticità e tessuto neoplastico Considerazioni di fisiopatologia"— Transcript della presentazione:
1Elasticità e tessuto neoplastico Considerazioni di fisiopatologia Antonio Pio MasciotraCampobasso-Molise-ItaliaSkype : antonio.masciotra
2Mechanical (elastic) properties of neoplastic tissue Physiopathology Antonio Pio MasciotraCampobasso-Molise-ItalySkype : antonio.masciotra
3Elastografia mammaria : quantitativa o qualitativa? Antonio Pio MasciotraCampobassoSkype : antonio.masciotra
4Breast sonoelastography : quantitative or qualitative? Antonio Pio MasciotraCampobasso-Molise-ItalySkype : antonio.masciotra
5PRINCIPAL MECHANICAL PROPERTIES Those characteristics of the materials which describe their behaviour under external loads are known as Mechanical Properties.The most important and useful mechanical properties are:StrengthIt is the resistance offered by a material when subjected to external loading.So, stronger the material the greater the load it can withstand.Depending upon the type of load applied the strength can be tensile, compressive, shear or torsional.The maximum stress that any material will withstand before destruction is called its ultimate strength.ElasticityElasticity of a material is its power of coming back to its original position after deformation when the stressor load is removed.Elasticity is a tensile property of its material.The greatest stress that a material can endure without taking up some permanent set is called elastic limit.Stiffness (Rigidity)The resistance of a material to deflection is called stiffness or rigidity.Steel is stiffer or more rigid than aluminium.Stiffness is measured by Young’s modulus E.The higher the value of the Young’s modulus, the stiffer the material.HardnessIt is the ability of a material to resist scratching, abrasion, indentation or penetration.
6PRINCIPALI PROPRIETA’ MECCANICHE Le caratteristiche dei materiali che descrivono il loro comportamento quando vengono sottoposti a carichi esterni vengono definite PROPRIETA’ MECCANICHE.Le più importanti di esse sono:FORZAE’ la resistenza offerta da un materiale quando viene sottoposto ad un carico esterno.Pertanto, quanto più forte è un materiale tanto maggiore sarà il carico che esso può sorreggere.ELASTICITA’E’ la capacità di un materiale a recuperare le sue posizione e forma iniziali dopo la rimozione di un carico od una forza, la cui applicazione ne aveva indotto la deformazione.STIFFNESS (RIGIDITA’)E’ la resistenza che un materiale oppone al suo ‘piegamento’.L’acciaio è più rigido dell’alluminio.La stiffness viene misurata dal Modulo di Young E.Quanto maggiore è il valore del modulo di Young tanto maggiore è la stiffness del materiale.DUREZZAE’ la capacità di un materiale a resistere al graffio, all’abrasione, alla scalfittura od alla penetrazione
9Stiffness distribution of cells and results of migration and invasion test Citation: Xu W, Mezencev R, Kim B, Wang L, McDonald J, et al. (2012)Cell Stiffness Is a Biomarker of the Metastatic Potential of Ovarian Cancer Cells.PLoS ONE 7(10): e doi: /journal.pone
10Normal cell toward cancer cell The distribution of the actin network plays an important role in determining the mechanical properties of single cells.As cells transform from non-malignant to cancerous states, their cytoskeletal structure changes from an organized to an irregular network, and this change subsequently reduces the stiffness of single cells.Further progressive reduction of stiffness corresponds to an increase in invasive and migratory capacity of malignant cells.Less invasiveNormal cell toward cancer cellSingle cell stiffness reductionMore invasive
11Mammary epithelial growth and morphogenesis is regulated by matrix stiffness. (A) 3D cultures of normal mammary epithelial cells within collagen gels of different concentration.Stiffening the ECM through an incremental increase in collagen concentration (soft gels: 1 mg/ml Collagen I, 140 Pa; stiff gels 3.6 mg/ml Collagen I, 1200 Pa) results in the progressive perturbation of morphogenesis, and the increased growth and modulated survival of MECs.Altered mammary acini morphology is illustrated by the destabilization of cell–cell adherens junctions and disruption of basal tissue polarity indicated by the gradual loss of cell–cell localized β-catenin (green) and disorganized β4 integrin (red) visualized throughimmunofluorescence and confocal imaging.Kass et al. Page 9Int J Biochem Cell Biol. Author manuscript; available in PMC 2009 March 19.NIH-PA
22Transizione da un ‘imaging’ ‘morfologico’ ad un’imaging fisiopatologico?
23Going from a morphologic to a physiopathologic ‘imaging’?
24Transizione da un ‘imaging’ ‘morfologico’ ad un’imaging fisiopatologico? SOFTVUESOFTVUE
25Going from a morphologic to a physiopathologic ‘imaging’? SOFTVUESOFTVUE
26Nell’Antico Egitto il riscontro di una massa dura nel corpo veniva correlata ad uno stato di malattia.Nella Medicina Ippocratica la palpazione era parte essenziale dell’esame fisico del paziente.Nel Terzo Millennio la «Palpazione Remota» sta diventando realtà grazie all’ Imaging Elastografico.
27In ancient Egypt, a link was established between a hard mass within the human body & pathology.In Hippocratic medicine, palpation wasan essential part of a physical examination.In the 21st century, «remote palpation» by meansof elastographic imaging is becoming a reality.
28Sonoelasticity: KJ Parker et al, 1990 Many R& D techniques have emerged since the 1990s, based on the Ultrasound and Magnetic Resonance imaging modalities.Sonoelasticity: KJ Parker et al, 1990Ultrasound Strain Elastography: J Ophir et al, 1991MR Elastography: R Sinkus et al, 2000Shear Wave Elastography: J Bercoff et al, 2004All techniques are based on the same principle:Generate a stress, and then use an imaging technique to map the tissue response to this stress in every point of the image.but differ substantially in terms of their performance characteristics:Qualitative / quantitative nature, absolute / relative quantification.Accuracy / precision / reproducibility, …Spatial / temporal resolution, sensitivity / penetration, …
29Initially introduced by Hitachi, and later on Siemens, in the early 2000s. More manufacturers have followed in the last year(s).The basic principle used is the one proposedby Ophir’s group in the early 1990s:Tissue compression (Stress) is inducedmanually by the user.Multiple images are recorded usingconventional imaging at standard frame rates.The relative deformation (Strain) is estimatedusing Tissue Doppler techniques.The derived strains are displayed asa qualitative elasticity image.
30Strain Elastography Summary Stress Source Manual Compression (user-dependent).Stress Frequency Static (user-induced vibration < 2 Hz).Result Type Qualitative image (E=Stress/Strain, but Stress is unknown).Relative quantification (Background-to-Lesion-Ratio).Straightforward implementation oncurrent scanners (standard acquisitionarchitecture, plus Tissue-Doppler-like processing)..Stress penetration / uniformity issues.User-applied compression is attenuated bysoft objects & depth and cannot penetrate hard-shelled lesions.User-dependence.User-applied compression is attenuated by soft objects & depth, and cannot penetrate hard-shelled lesions.
31SuperSonic Imagine has developed a novel method called SonicTouch, ExternalMechanical forceNaturalHeartSuperSonic Imagine has developed a novel method called SonicTouch,which is based on focused ultrasound, and can remotely generateShear Wave-fronts providing uniform coverage of a 2D area interest.
32Esempio di viscositàLa sostanza in basso ha maggior viscosità della sostanza acquosa in alto
33Viscosity demonstration The bottom substance has higher viscosity than the clear liquid above
34Strain vs. Shear Wave Elastography Strain Elastography tends to produce abinary classification, where the whole lesion is either hard or soft.Shear Wave Elastography provides richer & more complex information with many cases of hard borders plus soft centers.The differences between Strain and Shear Wave Elastography are not surprising, given the very different principles on which they are based.
35Shear Wave Elastography Phantom with liquid center inside hard lesionHighly-localized estimationof tissue elasticityEspecially, inside hard lesionsShear Wave Elastography can “see” insidethe hard lesion, because the shear wavescan propagate through the hard shell.Strain Elastography interprets the wholelesion as hard, because the applied manualcompression cannot penetrate the hard shell.
72Correct tissue elasticity quantification Aims of elastographyCorrect tissue elasticity quantificationIdentification of ‘cut off’ elasticity values for the right diagnostic workup of diffuse and focal diseases
73Breast lipomas SW Elastography precision and repeatibility Fat 19.9 kPa Lipoma 20.5 kPaSW Ratio 1.03Ore 10:07:09Fat 8.0 kPa Lipoma 7.8 kPaSW Ratio 1.03Ore 10:07:34
74Breast sonoelastography : Question n. 1 :quantitative or qualitative?Answer n. 1 Quantitative!Question n. 2 :SW or Strain Elastography?Answer n. 2 SW ElastographyAntonio Pio MasciotraCampobasso-Molise-ItalySkype : antonio.masciotra