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Introduction: Pelvic recurrences from rectal cancer present a challenging clinical scenario. Hyperthermia represents an innovative treatment option in combination with concurrent chemoradiation to enhance therapeutic effect. We provide the initial results of a prospective single center feasibility study (NCT02528175) for patients undergoing rectal cancer retreatment using concurrent chemoradiation and mild hyperthermia with MR-guided high intensity focused ultrasound (MR-HIFU). Methods: All patients were deemed ineligible for salvage surgery and were evaluated in a multidisciplinary fashion with a surgical oncologist, radiation oncologist and medical oncologist. Radiation was delivered to a dose of 30.6 Gy in 1.8 Gy per fraction with concurrent capecitabine. MR-HIFU was delivered on days 1, 8 and 15 of concurrent chemoradiation. Our primary objective was feasibility and toxicity. Results: Six patients (total 11 screened) were treated with concurrent chemoradiation and mild hyperthermia with MR-HIFU. Tumor size varied between 3.1-16.6 cm. Patients spent an average of 228 min in the MRI suite and sonication with the external transducer lasted an average of 35 min. There were no complications on the day of the MR-HIFU procedure and all acute toxicities (no grade >/=3 toxicities) resolved after completion of treatment. There were no late grade >/=3 toxicities. Conclusion: Mild hyperthermia with MR-HIFU, in combination with concurrent chemoradiation for appropriately selected patients, is safe for localized pelvic recurrences from rectal cancer. The potential for MR-HIFU to be applied in the recurrent setting in rectal cancer treatment requires further technical development and prospective evaluation. [ABSTRACT FROM AUTHOR]

This prospective, open-label trial (NCT04720469) screened 16 consecutive mrET patients who had undergone MRgFUS thalamotomy at least 1 year prior (MRgFUS SB 1 sb ). Herein, staged, bilateral MRgFUS thalamotomy was safe in a small sample of patients with mrET. Keywords: essential tremor; bilateral; thalamotomy; focused ultrasound; safety EN essential tremor bilateral thalamotomy focused ultrasound safety 1559 1561 3 10/24/23 20231001 NES 231001 Staged, open-surgical lesioning of the thalamic ventral intermediate nucleus to abate medication-refractory essential tremor (mrET) has been historically associated with a high frequency of adverse events (AEs), including speech and balance impairments.[1] More recently, the real-time imaging and thermometry guidance offered by magnetic resonance-guided focused ultrasound (MRgFUS) have allowed for minimally-invasive thalamotomies with increased focal accuracy to address upper limb tremor in ET patients.[2] Qualitative and semi-quantitative trials evaluating the safety of staged, bilateral MRgFUS thalamotomy have reported AEs that were mostly transient with mild to moderate severity based on patients' and physicians' perceived deficits.[[3], [5]] However, a comprehensive quantitative analysis of the potential post-thalamotomy changes in stance and gait balance (ie, equilibrium), and oro-motor function is lacking. We comprehensively evaluated the incidence and severity of AEs, including changes in equilibrium, speech, and cognition, following staged, bilateral MRgFUS thalamotomy for patients with mrET. [Extracted from the article]

Objective: To implement a skull-conformal phased array for ultrasound-guided transcranial focused ultrasound therapy with improved patient comfort. Methods: Using patient-specific computed tomography and MRI neuroimaging data, tightly-conforming helmet scaffolds were designed computationally. The helmet scaffolds were designed to hold reusable transducer modules at near-normal incidence in an optimal configuration for the treatment location(s) of interest. Numerical simulations of trans-skull ultrasound propagation were performed to evaluate different conformal array designs and to compare with hemispherical arrays similar to those employed clinically. A 4096-element phased array was constructed by 3D printing a helmet scaffold optimised for an ex vivo human skullcap, and its performance was evaluated via benchtop and in vivo experiments. Results: Acoustic field measurements confirmed the system's ability to focus through human skull bone using simulation-based transcranial aberration corrections. Preliminary in vivo testing demonstrated safe trans-human skull blood-brain barrier (BBB) opening in rodents. Conclusion: Patient-specific conformal ultrasound phased arrays appear to be a feasible and safe approach for conducting transcranial BBB opening procedures. Significance: Skull-conformal phased arrays stand to improve patient comfort and have the potential to accelerate the adoption of transcranial FUS therapy by improving access to the technology. [ABSTRACT FROM AUTHOR]

Abstract Background The Blood Brain Barrier (BBB) maintains the homeostasis of central nervous system by preventing the free passage of macromolecules from the systemic circulation into the brain. This normal physiological function of the BBB presents a challenge for delivery of therapeutic compounds into the brain. Recent studies have shown that the application of focused ultrasound together with ultrasound contrast agent (microbubbles) temporarily increases the permeability of the BBB. This effect is associated with breakdown of tight junctions, the structures that regulate the paracellular permeability of the endothelial cell layer. The influence of this ultrasound effect on the activation of intracellular signaling proteins is currently not well understood. Therefore, the aim of this study was to investigate the activation of cell survival signaling molecules in response to ultrasound-mediated BBB opening; Methods The BBB was disrupted in two four-spot lines (1-1.5 mm spacing) along the right hemisphere of rat brain with ultrasound beams (0.3 MPa, 120 s, 10 ms bursts, repetition frequency = 1 Hz) in the presence Definity microbubbles. Contrast-enhanced MRI images were acquired to assess the extent of BBB opening upon which the animals were sacrificed and the brains removed and processed for biochemical and immunohistochemical analyses; Results Immunoblotting of sonicated brain lysates resolved by SDS-PAGE demonstrated an increase in phosphorylation of Akt and its downstream signaling molecule, GSK3β, while the phosphorylation of MAPK remained unchanged. The elevated levels of pAkt and pGSK3β are still evident after 24 hours post-sonication, a time point where the integrity of the BBB is known to be re-established. Furthermore, immunofluoresence staining localized this increase in pAkt and pGSK3β levels to neuronal cells flanking the region of the disrupted BBB; Conclusions Our data demonstrates that ultrasound-mediated BBB disruption causes an activation of the Akt signaling pathway in neuronal cells surrounding the disrupted BBB.

Transcranial MR-guided focused ultrasound (MRgFUS) is a rapidly developing technology in neuroscience for manipulating brain structure and function without open surgery. The effectiveness of transcranial MRgFUS for thermoablation is well established, and the technique is actively employed worldwide for movement disorders including essential tremor. A growing number of centers are also investigating the potential of microbubble-mediated focused ultrasound-induced opening of the blood-brain barrier (BBB) for targeted drug delivery to the brain. Here, we provide a technical overview of the principles, clinical workflow, and operator considerations of transcranial MRgFUS procedures for both thermoablation and BBB opening. [ABSTRACT FROM AUTHOR]

The method of localized harmonic motion (LHM) monitoring has been proposed as an ultrasound-based monitoring technique for in vivo real-time ultrasound-guidance during thermal surgery. Objective: The focus of this paper is to study the performance of LHM monitoring in vivo in order to assess the tissue coagulation during ultrasound surgery of bone metastases. This is done through a pre-clinical study on large scale animals (pigs) as well as a first-in-human pilot study, using a hand held ultrasound-guided HIFU phased array. Methods: A flat, fully steerable HIFU phased array system (1024 elements, 100 mm diameter, 516 kHz), in combination with a co-aligned 64 element imaging system, is used to perform thermal surgery and monitor tissue coagulation using the LHM technique. The in vivo experiments are conducted using thirteen animals, followed by a first-in-human pilot study in which nine patients are enrolled. Results: The pre-clinical results show that the LHM monitoring method is able to detect about 80% of the observed coagulated tissue volumes visible in dissection. In the pilot study, six out of nine patients have durable pain reduction with good correlation observed from LHM detections. Conclusion: In general, the results suggest that the LHM monitoring performance is promising in detecting thermal tissue coagulation during focused ultrasound surgery in tissues close to the bone. Significance: The LHM technique can offer a very accessible and cost-efficient monitoring solution during ultrasound surgery within a clinical setting. [ABSTRACT FROM AUTHOR]