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- Sjostrand, Sandra, et al.
(författare)
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Contrast enhanced magneto-motive ultrasound in lymph nodes-modelling and pre-clinical imaging using magnetic microbubbles
- 2022
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Ingår i: 44th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2022. - 1557-170X. - 9781728127828 ; 2022-July, s. 194-197
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Konferensbidrag (refereegranskat)abstract
- Despite advances in MRI, the detection and characterisation of lymph nodes in rectal cancer remains complex, especially when assessing the response to neo-adjuvant treatment. An alternative approach is functional imaging, previously shown to aid characterization of cancer tissues. We report proof-of-concept of the novel technique Contrast-Enhanced Magneto-Motive Ultrasound (CE-MMUS) to recover information relating to local perfusion and lymphatic drainage, and interrogate tissue mechanical properties through magnetically induced tissue deformations. The feasibility of the proposed application was explored using a combination of pre-clinical ultrasound imaging and finite element analysis. First, contrast enhanced ultrasound imaging on one wild type mouse recorded lymphatic drainage of magnetic microbubbles after bolus injection. Second, preliminary CE-MMUS data were acquired as a proof of concept. Third, the magneto-mechanical interactions of a magnetic microbubble with an elastic solid were simulated using finite element software. Accumulation of magnetic microbubbles in the inguinal lymph node was verified using contrast enhanced ultrasound, with peak enhancement occurring 3.7 s post-injection. Preliminary CE-MMUS indicates the presence of magnetic contrast agent in the lymph node. The finite element analysis explores how the magnetic force is transferred to motion of the solid, which depends on elasticity and bubble radius, indicating an inverse relation with displacement. Combining magnetic microbubbles with MMUS could harness the advantages of both techniques, to provide perfusion information, robust lymph node delineation and characterisation based on mechanical properties. Clinical Relevance-Robust detection and characterisation of lymph nodes could be aided by visualising lymphatic drainage of magnetic microbubbles using contrast enhanced ultrasound imaging and magneto-motion, which is dependent on tissue mechanical properties.
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| 2. |
- Sjostrand, Sandra, et al.
(författare)
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Contrast-enhanced magnetomotive ultrasound imaging (CE-MMUS) for colorectal cancer staging : Assessment of sensitivity and resolution to detect alterations in tissue stiffness
- 2019
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Ingår i: 2019 IEEE International Ultrasonics Symposium, IUS 2019. - 1948-5719 .- 1948-5727. - 9781728145976 - 9781728145969 ; 2019-October, s. 1077-1080
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Konferensbidrag (refereegranskat)abstract
- A key challenge in the treatment of colorectal cancer is identification of the sentinel draining lymph node. Magnetomotive ultrasound, MMUS, has identified lymph nodes in rat models: superparamagnetic iron oxide nanoparticles (SPIONs) accumulated in the lymph are forced to oscillate by an external magnetic field; the resulting axial displacement is recovered allowing structure delineation with potential to indicate alterations in tissue stiffness, but it is limited by small vibration amplitudes. We propose CE-MMUS using SPION loaded microbubbles (SPION-MBs) to enhance sensitivity, reduce toxicity, and offer additional diagnostic or perfusion information. Laser doppler vibrometry measurements was performed on SPION containing tissue mimicking material during magnetic excitation. These measurements show a vibration amplitude of 279 ± 113 μm in a material with Young's modulus of 24.3 ± 2.8 kPa, while the displacements were substantially larger, 426 ± 9 μm, in the softer material, with a Young's modulus of 9.6 ± 0.8 kPa. Magnetic field measurement data was used to calibrate finite element modelling of both MMUS and CE-MMUS. SPION-MBs were shown to be capable of inducing larger tissue displacements under a given magnetic field than SPIONs alone, leading to axial displacements of up to 2.3x larger. A doubling in tissue stiffness (as may occur in cancer) reduces the vibration amplitude. Thus, there is potential for CE-MMUS to achieve improved stiffness sensitivity. Our aim is to define the potential contribution of CE-MMUS in colorectal cancer diagnosis and surgical guidance.
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