MR Elastography of the Liver and the Spleen Using a Piezoelectric Driver, Single‐Shot Wave‐Field Acquisition, and Multifrequency Dual Parameter Reconstruction

Hirsch, Sebastian; Guo, Jing; Reiter, Rolf; Papazoglou, Sebastian; Kroencke, Thomas J.; Braun, Jürgen; Sack, Ingolf

doi:10.1002/mrm.24674

Cited by 110 publications

(132 citation statements)

References 47 publications

(108 reference statements)

Supporting

Mentioning

125

Contrasting

Unclassified

Order By: Relevance

“…The vibrations were transferred from the tip of the lever to the patient by a carbon fiber rod connected at its distal end to a rubber mat. The transducer mat was moderately pressed onto the body surface in the position just below the right costal arch using Velcro strips attached to the patient table [14]. All experiments were conducted on a 1.5-T MRI scanner (Magnetom Sonata; Siemens Erlangen, Germany) equipped with a 12-channel phased-array surface coil.…”

Section: D-mmrementioning

confidence: 99%

“…1 Experimental setup of patient-activated 3D-MMRE. Details of the MRE sequence and the nonmagnetic vibration generator are given in [14]. The novel patient-activated respiratory gating system is described in the method section.…”

Section: Data Processingmentioning

confidence: 99%

“…1 Experimenteller Aufbau für patientenaktivierte 3-D-MMRE. Details über die MRE-Sequenz und den nichtmagnetischen Vibrationserzeuger sind in [14] publiziert. Der neuartige patientenaktivierte Trigger ist im Methodenteil beschrieben.…”

Section: Data Processingunclassified

“…To reduce such wave voids, multifrequency inversion was recently introduced, which adds wave fields of different drive frequencies to the solution of an overdetermined system of wave equations [18]. As a result, the accuracy of elastograms can be greatly improved, depending on the amount of information combined into a single inversion step [14]. In this approach, the major limiting factor for improving the quality of elastograms is the duration of image acquisition.…”

mentioning

confidence: 99%

“…Previous hepatic MRE studies were run in 3D at single drive frequency [20 -22] or at multiple frequencies in 2 D [13,23] with voxel volumes of 64 mm³ or larger. Recently, we introduced 3D multifrequency MRE (3D-MMRE) with four vibration frequencies and an image resolution of 2.7 × 2.7 × 5 mm³ for better resolved and less biased MRE of the liver and spleen [14]. In order to further improve the resolution of abdominal MRE, the quality of the wave images has to be increased (for improved detail resolution of anatomical structures) and more vibration frequencies should be applied (in order to stabilize the inversion by independent wave fields) [18].…”

mentioning

confidence: 99%

See 4 more Smart Citations

Patient-Activated Three-Dimensional Multifrequency Magnetic Resonance Elastography for High-Resolution Mechanical Imaging of the Liver and Spleen

Guo

Hirsch

Streitberger

et al. 2013

Fortschr Röntgenstr

View full text Add to dashboard Cite

Purpose: To introduce a novel in-vivo three-dimensional multifrequency magnetic resonance elastography (3D-MMRE) method for high-resolution mechanical characterization of the liver and spleen. Materials and Methods: Ten healthy volunteers were examined by abdominal single-shot 3D-MMRE using a novel patient-activated trigger system with respiratory control. 10 contiguous slices with 2.5?mm cubic voxel resolution, 3 wave components, 8 time steps, and 2 averages were acquired at 7 mechanical excitation frequencies from 30 to 60?Hz. The total imaging time was approximately 15?min. For postprocessing, multifrequency dual elasto-visco (MDEV) inversion was used to calculate high-resolution mechanical parameter maps of the abdomen including the liver and spleen. Results: Two parameters maps were generated from each image slice to capture the magnitude and the phase angle of the complex shear modulus. Both parameters depicted the mechanical structures of the abdomen with unprecedented high spatial resolution. Spatially averaged group mean values of the liver and spleen are 1.27???0.17 kPa and 2.01???0.69 kPa, indicating a significantly higher asymptomatic stiffness of the spleen compared to the liver. Conclusion: Patient-activated respiratory-gated 3D-MMRE combined with MDEV inversion provides highly resolved mechanical maps of the liver and spleen that are superior to previous elastograms measured by abdominal MRE. Citation Format: ??Guo J, Hirsch S, Streitberger KJ et?al. Patient-Activated Three-Dimensional Multifrequency Magnetic Resonance Elastography for High-Resolution Mechanical Imaging of the Liver and Spleen. Fortschr R?ntgenstr 2014; 186: 260???266

show abstract

Section: D-mmrementioning

confidence: 99%

Section: Data Processingmentioning

confidence: 99%

Section: Data Processingunclassified

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Patient-Activated Three-Dimensional Multifrequency Magnetic Resonance Elastography for High-Resolution Mechanical Imaging of the Liver and Spleen

Guo

Hirsch

Streitberger

et al. 2013

Fortschr Röntgenstr

View full text Add to dashboard Cite

show abstract

References

2016

Magnetic Resonance Elastography

View full text Add to dashboard Cite

Engineering an Artificial T‐Cell Stimulating Matrix for Immunotherapy

Hickey¹,

Dong

Chung³

et al. 2019

Advanced Materials

View full text Add to dashboard Cite

T cell therapies require the removal and culture of T cells ex vivo to expand several thousandfold. However, these cells often lose the phenotype and cytotoxic functionality necessary to mediate an effective therapeutic response. The extracellular matrix has been used to preserve and augment cell phenotype; however, it has not been applied to cellular immunotherapies.Here we engineered a hyaluronic acid (HA)-based hydrogel to present the two stimulatory signals required for T-cell activation-termed an artificial T cell stimulating matrix (aTM).We found that biophysical properties of the aTM-stimulatory ligand density, stiffness, and extracellular matrix (ECM) proteins-potentiate T cell signaling and skew phenotype of both murine and human T cells. Importantly, it was only the combination of the ECM environment and mechanically sensitive TCR signaling from the aTM that produced nearly 4-times the number of rare, antigen-specific CD8+ T cells. Adoptive transfer of these tumor-specific cells significantly suppressed tumor growth and improved animal survival as compared with T cells stimulated by traditional methods. Beyond immediate immunotherapeutic applications, demonstrating that the environment influences the cellular therapeutic product delineates the importance of the ECM and provides a case study of how to engineer ECM-mimetic materials for therapeutic immune stimulation in the future.

show abstract

MR Elastography of the Liver and the Spleen Using a Piezoelectric Driver, Single‐Shot Wave‐Field Acquisition, and Multifrequency Dual Parameter Reconstruction

Abstract: The proposed method provides abdominal images of viscoelasticity in a short time with spatial resolution comparable to conventional MR images and improved quality without being compromised by ascites. The new setup allows for the integration of abdominal MRE into the clinical workflow.

Cited by 110 publications

References 47 publications

Patient-Activated Three-Dimensional Multifrequency Magnetic Resonance Elastography for High-Resolution Mechanical Imaging of the Liver and Spleen

Patient-Activated Three-Dimensional Multifrequency Magnetic Resonance Elastography for High-Resolution Mechanical Imaging of the Liver and Spleen

References

Engineering an Artificial T‐Cell Stimulating Matrix for Immunotherapy

Contact Info

Product

Resources

About