Name: viscoelastic characterization of soft tissue-mimicking gelatin phantoms using indentation and magnetic resonance elastography
Uploaded: 2022-05-10T15:00:00
Description: Watch this Scientific Journal Video about Viscoelastic Characterization of Soft Tissue-Mimicking Gelatin Phantoms using Indentation and Magnetic Resonance Elastography at JoVE.com

Funding support from the National Natural Science Foundation of China (grant 31870941), Natural Science Foundation of Shanghai (grant 22ZR1429600), and the Science and Technology Commission of Shanghai Municipality (grant 19441907700) is acknowledged.

1. Gelatin phantom preparation
<ol>
	<li>Weigh gelatin, glycerol, and water according to Table 1. Mix the gelatin powder with water to obtain the gelatin solution. 
	NOTE: The concentrations of the individual components for preparing the two phantoms are shown in Table 1. The higher the concentration of gelatin, the stiffer the phantom.</li>
	<li>Heat the gelatin solution to 60 &#176;C in a water bath. Add glycerol to the gelatin solution while maintaining the tem...

<ol>
	<li>Qiu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viscoelastic+characterization+of+injured+brain+tissue+after+controlled+cortical+impact+(CCI)+using+a+mouse+model.">Viscoelastic characterization of injured brain tissue after controlled cortical impact (CCI) using a mouse model.</a> Journal of Neuroscience Methods. 330, 108463 (2020).</li><li>Garcia, K. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+patterns+of+cortical+expansion+during+folding+of+the+preterm+human+brain.">Dynamic patterns of cortical expansion during folding of the preterm human brain.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (12), 3156-3161 (2018).</li><li>Qiu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+viscoelastic+properties+of+breast+cancer+tissue+in+a+mouse+model+using+indentation.">Characterizing viscoelastic properties of breast cancer tissue in a mouse model using indentation.</a> Journal of Biomechanics. 69, 81-89 (2018).</li><li>Yin, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+method+for+quantification+and+3D+visualization+of+brain+tumor+adhesion+using+slip+interface+imaging+in+patients+with+meningiomas.">A new method for quantification and 3D visualization of brain tumor adhesion using slip interface imaging in patients with meningiomas.</a> European Radiology. 31 (8), 5554-5564 (2021).</li><li>Streitberger, K. -. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+tissue+fluidity+influences+brain+tumor+progression.">How tissue fluidity influences brain tumor progression.</a> Proceedings of the National Academy of Sciences of the United States of America. 117 (1), 128 (2020).</li><li>Bunevicius, A., Schregel, K., Sinkus, R., Golby, A., Patz, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=REVIEW:+MR+elastography+of+brain+tumors.">REVIEW: MR elastography of brain tumors.</a> NeuroImage: Clinical. 25, 102109 (2020).</li><li>Namani, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elastic+characterization+of+transversely+isotropic+soft+materials+by+dynamic+shear+and+asymmetric+indentation.">Elastic characterization of transversely isotropic soft materials by dynamic shear and asymmetric indentation.</a> Journal of Biomechanical Engineering. 134 (6), 061004 (2012).</li><li>Potter, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+small-specimen+planar+biaxial+testing+system+with+full+in-plane+deformation+control.">A novel small-specimen planar biaxial testing system with full in-plane deformation control.</a> Journal of Biomechanical Engineering. 140 (5), 0510011 (2018).</li><li>Zhang, W., Feng, Y., Lee, C. -. 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V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viscoelastic+properties+of+soft+gels:+comparison+of+magnetic+resonance+elastography+and+dynamic+shear+testing+in+the+shear+wave+regime.">Viscoelastic properties of soft gels: comparison of magnetic resonance elastography and dynamic shear testing in the shear wave regime.</a> Physics in Medicine and Biology. 56 (19), 6379-6400 (2011).</li><li>Feng, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+multi-purpose+electromagnetic+actuator+for+magnetic+resonance+elastography.">A multi-purpose electromagnetic actuator for magnetic resonance elastography.</a> Magnetic Resonance Imaging. 51, 29-34 (2018).</li><li>Zeng, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonlinear+inversion+MR+elastography+with+low-frequency+actuation.">Nonlinear inversion MR elastography with low-frequency actuation.</a> IEEE Transactions on Medical Imaging. 39 (5), 1775-1784 (2020).</li><li>Wang, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+magnetic+resonance+elastography+with+multiphase+radial+encoding+and+harmonic+motion+sparsity+based+reconstruction.">Fast magnetic resonance elastography with multiphase radial encoding and harmonic motion sparsity based reconstruction.</a> Physics in Medicine and Biology. 67 (2), (2022).</li><li>Herraez, M. 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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MR+elastography+at+1+of+gelatin+phantoms+using+3D+or+4D+acquisition.">MR elastography at 1 of gelatin phantoms using 3D or 4D acquisition.</a> Journal of Magnetic Resonance. 296, 112-120 (2018).</li><li>McGarry, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniqueness+of+poroelastic+and+viscoelastic+nonlinear+inversion+MR+elastography+at+low+frequencies.">Uniqueness of poroelastic and viscoelastic nonlinear inversion MR elastography at low frequencies.</a> Physics in Medicine and Biology. 64 (7), 075006 (2019).</li><li>Zampini, M. A., Guidetti, M., Royston, T. 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Gelatin phantoms are commonly used as tissue-mimicking materials for testing and validation of algorithms and devices17,19,22,23,24,25,26,27. One of the pioneering studies using the gelatin phantom to compare MRE and dynamic shear testing was presented by O...

Most of the soft biological tissues appear to have viscoelastic properties that are important to understand their injury and development1,2. In addition, viscoelastic properties are important biomarkers in the diagnosis of a variety of diseases such as fibrosis and cancer3,4,5,6. Therefore, the characterization of viscoelastic properties of soft tissues is crucial. Among the many characterization techniques used, ex vivo mechanical testing of tissue samples and in vivo elastography using biomedical imaging are the two widely used methods.
Although various mechanical testing techniques have been used for soft tissue characterization, the requirements for sample size and testing conditions are not easy to be satisfied. For example, shear testing needs to have samples fixed firmly between the shear plates7. Biaxial testing is more suitable for membrane tissue and has specific clamping requirements8,9. A compression test is commonly used for tissue testing, but cannot characterize specific positions within one sample10. The indentation test does not have additional requirements to fix the tissue sample and can be used to measure many biological tissue samples such as the brain and liver. In addition, with a small indenter head, regional properties within a sample could be tested. Therefore, indentation tests have been adopted to test a variety of soft tissues1,3,11.
Characterizing the biomechanical properties of soft tissues in vivo is important for translational studies and clinical applications of biomechanics. Biomedical imaging modalities such as ultrasound (US) and magnetic resonance (MR) imaging are the most used techniques. Although US imaging is relatively cheap and easy to carry out, it suffers from low contrast and is hard to measure organs such as the brain. Capable of imaging deep structures, MR Elastography (MRE) could measure a variety of soft tissues6,12, especially the brain13,14. With applied external vibration, MRE could measure the viscoelastic properties of soft tissues at a specific frequency.
Studies have shown that at 50-60 Hz, the shear modulus of the normal brain is ~1.5-2.5kPa5,6,13,14,15 and ~2-2.5 kPa for normal liver16. Therefore, gelatin phantoms that have similar biomechanical properties have been widely used for mimicking soft tissues for testing and validation17,18,19. In this protocol, gelatin phantoms with two different concentrations were prepared and tested. Viscoelastic properties of the gelatin phantoms were characterized using a custom-built electromagnetic MRE device14 and an indentation device1,3. The testing protocols could be used for testing many soft tissues such as the brain or liver.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>24-channel head &#38; Neck coil</td>
			<td>United Imaging Healthcare</td>
			<td>100120</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>3T MR Scanner</td>
			<td>United Imaging Healthcare</td>
			<td>uMR 790</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Acquisition board</td>
			<td>Advantech Co</td>
			<td>PCI-1706U</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Computer-Windows</td>
			<td>HP</td>
			<td>790-07</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Electromagnetic actuator</td>
			<td>Shanghai Jiao Tong University</td>
			<td></td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Function generator</td>
			<td>RIGOL</td>
			<td>DG1022Z</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Gelatin</td>
			<td>CARTE D&#8217;OR</td>
			<td></td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Vance Bioenergy Sdn.Bhd</td>
			<td></td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Indenter control program</td>
			<td>custom-designed</td>
			<td></td>
			<td>Software; accessed via: https://github.com/aaronfeng369/FengLab_indentation_code.</td>
		</tr>
		<tr>
			<td>Laser sensor</td>
			<td>Panasonic</td>
			<td>HG-C1050</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Load cell</td>
			<td>Transducer Technique</td>
			<td>GSO-10</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>Mathworks</td>
			<td></td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Power amplifier</td>
			<td>Yamaha</td>
			<td>A-S201</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Voice coil electric motor</td>
			<td>SMAC Corporation</td>
			<td>DB2583</td>
			<td>Equipment</td>
		</tr>
	</tbody>
</table>

viscoelastic characterization of soft tissue-mimicking gelatin phantoms using indentation and magnetic resonance elastography

Characterization of biomechanical properties of soft biological tissues is important to understand the tissue mechanics and explore the biomechanics-related mechanisms of disease, injury, and development. The mechanical testing method is the most straightforward way for tissue characterization and is considered as verification for in vivo measurement. Among the many ex vivo mechanical testing techniques, the indentation test provides a reliable way, especially for samples that are small, hard to fix, and viscoelastic such as brain tissue. Magnetic resonance elastography (MRE) is a clinically used method to measure the biomechanical properties of soft tissues. Based on shear wave propagation in soft tissues recorded using MRE, viscoelastic properties of soft tissues can be estimated in vivo based on wave equation. Here, the viscoelastic properties of gelatin phantoms with two different concentrations were measured by MRE and indentation. The protocols of phantom fabrication, testing, and modulus estimation have been presented.

Following the MRE protocol, a clear shear wave propagation in the gelatin phantoms at 40 and 50 Hz were observed (Figure 3). The viscoelastic properties measured from MRE, and indentation tests are shown in Figure 4. The estimated G&#39; and G&#34; values at each testing for each phantom are summarized in Table 2. Following the indentation protocol, the viscoelastic properties of each phantom at each test point are summarized in Table 3<...

Watch this Scientific Journal Video about Viscoelastic Characterization of Soft Tissue-Mimicking Gelatin Phantoms using Indentation and Magnetic Resonance Elastography at JoVE.com

Viscoelastic Characterization of Soft Tissue-Mimicking Gelatin Phantoms using Indentation and Magnetic Resonance Elastography

This article presents a demonstration and summary of protocols of making gelatin phantoms that mimic soft tissues, and the corresponding viscoelastic characterization using indentation and magnetic resonance elastography.

Characterization of biomechanical properties of soft biological tissues is important to understand the tissue mechanics and explore the ...

Questo protocollo fornisce un modo per preparare le funzioni del gel che imitano i tessuti nei metodi di caratterizzazione biomeccanica ex vivo e in vivo, che sono fondamentali per comprendere e trovare nuovi biomarcatori per il tessuto L'indentazione può misurare campioni di tessuto di piccole dimensioni ed è facile da eseguire mentre lo stesso campione può essere testato utilizzando la risonanza magnetica, fornendo una stima diretta degli scenari di test in vivo. Questo metodo potrebbe fornire informazioni sulle proprietà meccaniche dipendenti dalla frequenza viscoelastica di campioni biologici molli, come il cervello, il fegato, i tessuti tumorali, eccetera. È inoltre possibile misurare proprietà simili di altri fantocci campione.Iniziare mescolando la polvere di gelatina con acqua per ottenere la soluzione di gelatina. Riscaldare la soluzione di gelatina a 60 gradi Celsius a bagnomaria e aggiungere glicerolo alla soluzione mantenendo la temperatura. Mescolare la soluzione e riscaldarla nuovamente a 60 gradi Celsius.Versare la soluzione miscelata in un contenitore che verrà utilizzato per i test MRE e di indentazione. Raffreddare la soluzione a temperatura ambiente e attendere che la soluzione si solidifichi. Posizionare il fantasma di gelatina nella bobina della testa.Quindi, mettere la piastra vibrante sopra il fantasma di gelatina. Assicurarsi che il contatto tra il fantasma e la piastra vibrante sia salda. Metti spugne e sacchetti di sabbia intorno al fantasma di gelatina per assicurarti che il fantasma sia saldamente posizionato.Montare un attuatore elettromagnetico sulla bobina della testa e collegare la barra di trasmissione alla piastra vibrante. Collegare le linee di alimentazione dell'attuatore con l'amplificatore e quindi collegare le linee di controllo con il controller. Impostare la forma d'onda, la frequenza di vibrazione e l'ampiezza nel generatore di funzioni.Impostare l'ampiezza di vibrazione desiderata regolando l'amplificatore di potenza. Quindi, impostare il generatore di funzioni in modo che funzioni in modalità trigger. Collegare la linea di trigger alla porta di trigger esterna della macchina MRI.Impostare la frequenza di scansione MRE uguale a quella del generatore di funzioni, in modo che il gradiente di codifica del movimento sia sincronizzato con il movimento della piastra vibrante. Quindi, impostare l'angolo di rotazione su 30 gradi, TR e TE su 50 e 31 millisecondi, il campo visivo su 300 millimetri, lo spessore della fetta su cinque millimetri e la dimensione del voxel su 2,34 per 2,34 millimetri quadrati. Misurare le immagini di fase in quattro punti temporali in un ciclo sinusoidale.Applicare gradienti di movimento e codifica sia positivi che negativi in ogni punto temporale. In base all'immagine di fase acquisita, rimuovere la fase di sfondo sottraendo le immagini di fase codificate positive e negative. Scartare la fase con un algoritmo basato sull'ordinamento dell'affidabilità.Estraete le componenti principali del moto applicando la trasformata di Fourier veloce alle immagini di fase non avvolte. Filtrare l'immagine di fase con un filtro passa banda digitale e stimare il modulo di taglio con un algoritmo di inversione diretta 2D per ottenere il modulo di memorizzazione G-prime e il modulo di perdita G-doppio primo. Utilizzare un punzone circolare per tagliare il fantasma di gelatina in un campione cilindrico e utilizzare una lama chirurgica per tagliarlo in un campione cuboide.Rifilare la superficie del campione con una lama affilata per renderla il più liscia possibile per la rientranza. Accendere il tester di indentazione e fare clic sul pulsante Back Off nella GUI per inizializzare il processo di calibrazione. Leggere il valore dal sensore laser e digitare il valore nella casella BaseLine.Posizionare un vetrino sulla piastra del deflettore e registrare il valore mostrato dal sensore laser. Quindi, mettere il campione sul vetrino e posizionarli insieme sulla piastra del deflettore. Leggere il valore dal sensore laser e digitarlo nella casella Diapositiva campione.La differenza tra questi due valori è lo spessore del campione nella regione di interesse. Posizionare con attenzione il campione insieme al vetrino sottostante proprio sotto l'indentatore, quindi fare clic sul pulsante Contatto per avviare il contatto automatico tra il rientrante e la superficie del campione. In base allo spessore del campione misurato, stimare lo spostamento di rientro moltiplicando lo spessore con la deformazione di prova rientrata.Immettete i valori di spostamento nella casella Spostamento (Displacement). Impostare il tempo di rilassamento su 180 secondi nella casella Tempo di permanenza e fare clic sul pulsante Rientro. Lo spostamento e la forza reattiva durante la procedura di rampa/mantenimento verranno automaticamente registrati e salvati in un file nel percorso del file specificato.Le immagini di propagazione delle onde per i due fantocci di gelatina a 40 e 50 hertz sono mostrate qui. Le quattro fasi corrispondono ai quattro punti temporali in un ciclo sinusoidale. Le proprietà viscoelastiche misurate da MRE e esperimenti di indentazione sono mostrate qui.Le immagini rappresentative raffigurano le tipiche mappe stimate G-prime e G-doppio primo a 40 e 50 hertz per i due fantocci di gelatina della MRE. La deviazione media e standard dei valori G-zero e G-infinito per i due fantocci dei sei test di indentazione ripetuti sono presentati qui. Le immagini grafiche mostrate sullo schermo rappresentano la media e la deviazione standard dei valori primi G e G-doppi primi a 40 e 50 hertz per i due fantocci dei sei test MRE ripetuti.Il simbolo dell'asterisco indica una differenza significativa. Quando si tenta questa procedura, assicurarsi che la piastra vibrante sia premuta saldamente sopra il fantasma e non premere eccessivamente la piastra. Quando si tratta il campione, assicurarsi che la superficie sia il più piatta possibile.Questa tecnica apre la strada all'esplorazione delle proprietà biomeccaniche relative agli studi patologici e allo sviluppo di biomarcatori basati sulla biomeccanica per la diagnosi e la prognosi delle malattie.

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Magnetic Resonance Elastography Methodology for the Evaluation of Tissue Engineered Construct Growth

Metodologia Elastografia risonanza magnetica per la valutazione dei Tissue Engineered Construct crescita

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use ...

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Bioingegneria

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

Magneticamente-Assisted Remote Controlled Suggerimento Flessione Microcatetere in Risonanza Magnetica

X-ray fluoroscopy-guided  endovascular procedures have several significant limitations, including  difficult catheter navigation and use of ionizing ...

Construction of a Preclinical Multimodality Phantom Using Tissue-mimicking Materials for Quality Assurance in Tumor Size Measurement

Costruzione di un Phantom multimodalità preclinici Uso dei materiali di tessuti che imitano per l&#39;assicurazione della qualità delle dimensioni del tumore Misura

World Health Organization (WHO) and the Response Evaluation Criteria in Solid Tumors (RECIST) working groups advocated standardized criteria for ...

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release

Alternando microgel ibrida Gelatina di campo magnetico-Responsive per Controlled Drug uscita

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of ...

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

Rapid Scan paramagnetica elettronica Risonanza apre nuove strade per l&#39;imaging Fisiologicamente parametri importanti<em&gt; In Vivo</em

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Caratterizzazione biomeccanica di morbidi tessuti umani usando una indentazione e prove di trazione

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

Metabolic Support of Excised, Living Brain Tissues During Magnetic Resonance Microscopy Acquisition

Supporto metabolico di asportato, tessuti di cervello viventi durante l'acquisizione di microscopia a risonanza magnetica

This protocol describes the procedures necessary to support normal metabolic functions of acute brain slice preparations during the collection of magnetic ...

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

Fabbricazione e caratterizzazione dei fantasmi di tessuto ottico contenente macrostruttura

The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By ...

Agarose-based Tissue Mimicking Optical Phantoms for Diffuse Reflectance Spectroscopy

Agarosio-basata del tessuto che imita Phantoms ottico per spettroscopia di riflettanza diffusa

This protocol describes how to make agarose-based tissue-mimicking phantoms and demonstrates how to determine their optical properties using a ...

Manufacturing Abdominal Aorta Hydrogel Tissue-Mimicking Phantoms for Ultrasound Elastography Validation

Aorta addominale idrogel che imita tessuto di fabbricazione fantocci per convalida Elastografia ad ultrasuoni

Ultrasound (US) elastography, or elasticity imaging, is an adjunct imaging technique that utilizes sequential US images of soft tissues to measure the ...