Fluid filling of the digestive tract for improved proton resonance frequency shift‐based MR thermometry in the pancreas

Ferrer, Cyril J.; Bartels, Lambertus W.; Stralen, Marijn van; Moonen, Chrit; Bos, Clemens

doi:10.1002/jmri.25800

Cited by 6 publications

(5 citation statements)

References 26 publications

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“…Realtime temperature and motion monitoring would play a major role in this treatment procedure. Some online tools have been already proposed to achieve these tasks but it would be needed to evaluate them in this context [15,[37][38][39][40][41]. Future work should include pre-clinical and clinical experiments to demonstrate its in-vivo feasibility with actual HIFU heating.…”

Section: Discussionmentioning

confidence: 99%

A planning strategy for combined motion-assisted/gated MR guided focused ultrasound treatment of the pancreas

Ferrer

Bos

Borman

et al. 2019

International Journal of Hyperthermia

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Objective: To develop and evaluate a combined motion-assisted/gated MRHIFU heating strategy designed to accelerate the treatment procedure by reducing the required number of sonications to ablate a target volume in the pancreas. Methods: A planning method for combined motion-assisted/gated MRHIFU using 4D-MRI and motion characterization is introduced. Six healthy volunteers underwent 4D-MRI for target motion characterization on a 3.0-T clinical scanner. Using displacement patterns, simulations were performed for all volunteers for three sonication approaches: gated, combined motion-assisted/gated, and static. The number of sonications needed to ablate the pancreas head was compared. The influence of displacement amplitude and target volume size was investigated. Spherical target volumes (8, 15, 20 and 34 mL) and displacement amplitudes ranging from 5 to 25 mm were evaluated. For this case, the number of sonications required to ablate the whole target was determined. Results: The number of required sonications was lowest for a static target, 62 on average (range 49-78). The gated approach required most sonications, 126 (range 97-159). The combined approach was almost as efficient as the hypothetical static case, with an average of 78 (range 53-123). Simulations showed that with a 5-mm displacement amplitude, the target could be treated by making use of motion-assisted MRHIFU sonications only. In that case, this approach allowed the lowest number of sonication, while for 10 mm and above, the number of required sonications increased. Conclusion: The use of a combined motion-assisted/gated MRHIFU strategy may accelerate tumor ablation in the pancreas when respiratory-induced displacement amplitudes are between 5 and 10 mm. ARTICLE HISTORYThermal ablation; high intensity focused ultrasound; imaging (i.e.; MRI); modeling (i.e.; treatment planning)

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Section: Discussionmentioning

confidence: 99%

A planning strategy for combined motion-assisted/gated MR guided focused ultrasound treatment of the pancreas

Ferrer

Bos

Borman

et al. 2019

International Journal of Hyperthermia

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“…A polyacrylamide spacer with a drop-shaped dome, which displaced the bowels and thereby facilitated acoustic access to the pancreas, was interposed between the HIFU window and the animal (Figure 1). The influence of a similar spacer on the quality of temperature mapping was studied previously by Ferrer et al [73]. A thin layer of degassed and demineralized water was applied to the HIFU window to establish acoustic coupling to the spacer.…”

Section: Methodsmentioning

confidence: 99%

Feasibility study of MR-guided pancreas ablation using high-intensity focused ultrasound in a healthy swine model

Sebeke

Rademann

Maul

et al. 2020

International Journal of Hyperthermia

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Purpose: Pancreatic cancer is typically diagnosed in a late stage with limited therapeutic options. For those patients, ultrasound-guided high-intensity focused ultrasound (US-HIFU) can improve local control and alleviate pain. However, MRI-guided HIFU (MR-HIFU) has not yet been studied extensively in this context. To facilitate related research and accelerate clinical translation, we report a workflow for the in vivo HIFU ablation of the porcine pancreas under MRI guidance. Materials and methods: The pancreases of five healthy German landrace pigs (35-58 kg) were sonicated using a clinical MR-HIFU system. Acoustic access to the pancreas was supported by a specialized diet and a hydrogel compression device for bowel displacement. Organ motion was suspended using periods of apnea. The size of the resulting thermal lesions was assessed using the thermal thresholdand dose profiles, non-perfused volume, and gross examination. The effect of the compression device on beam path length was assessed using MRI imaging. Results: Eight of ten treatments resulted in clearly visible damage in the target tissue upon gross examination. Five treatments resulted in coagulative necrosis. Good agreement between the four metrics for lesion size and a clear correlation between the delivered energy dose and the resulting lesion size were found. The compression device notably shortened the intra-abdominal beam path. Conclusions: We demonstrated a workflow for HIFU treatment of the porcine pancreas in-vivo under MRI-guidance. This development bears significance for the development of MR-guided HIFU interventions on the pancreas as the pig is the preferred animal model for the translation of pre-clinical research into clinical application.

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“…Chemical shifts of protons from fatty acid chains (e.g., from the methylene protons) do not significantly change with temperature (see also subsection "Beyond Classical Phase-Based PRF and MR Spectroscopy: New Alternative MRI Thermometry in the Presence of Fat"). Therefore, PRF-based thermometry cannot be applied to fatty tissues but has recently been combined with T 1 -based thermometry to create temperature maps from body regions that contain both aqueous and adipose tissues (Zhang et al, 2019); see also Table S1 iScience Review filling the digestive tract with an appropriate fluid (here, pineapple juice) to exclude the presence of bowel gas close to the tissue volume to be studied (Ferrer et al, 2018). The authors have experimentally shown that, with respiratory gating and motion compensation, but without bowel filling, the standard deviation may amount to about 10 C in the pancreas head, which would lead to problems in treatment evaluation and safety monitoring during thermal therapy.…”

Section: The Methodological Groundwork: Advances In Mrs and Mri Temperature Methodsmentioning

confidence: 99%

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

Lutz¹,

Bernard²

2020

iScience

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Control of temperature variation is of primordial importance in particular areas of biomedicine. In this context, medical treatments such as hyperthermia and cryotherapy, but also the development and use of hydrogel-based biomaterials are of particular concern. To enable accurate temperature measurement without perturbing or even destroying the biological tissue or material to be monitored, contactless thermometry methods are preferred. Among these, the most suitable are based on magnetic resonance imaging and spectroscopy (MRI, MRS). Here, we address the latest developments in this field as well as their current and anticipated practical applications. We highlight recent progress aimed at rendering MR thermometry faster and more reproducible, versatile and sophisticated, and provide our perspective on how these new techniques broaden the range of applications in medical treatments and biomaterial development by enabling insight into finer details of thermal behavior. Thus, these methods facilitate optimization of clinical and industrial heating and cooling protocols.

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Fluid filling of the digestive tract for improved proton resonance frequency shift‐based MR thermometry in the pancreas

Abstract: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:692-701.

Cited by 6 publications

References 26 publications

A planning strategy for combined motion-assisted/gated MR guided focused ultrasound treatment of the pancreas

A planning strategy for combined motion-assisted/gated MR guided focused ultrasound treatment of the pancreas

Feasibility study of MR-guided pancreas ablation using high-intensity focused ultrasound in a healthy swine model

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

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