A Breast-Specific MR Guided Focused Ultrasound Platform and Treatment Protocol: First-in-Human Technical Evaluation.

Objective: This paper presents and evaluates a breast-specific magnetic resonance guided focused ultrasound (MRgFUS) system. A first-in-human evaluation demonstrates the novel hardware, a sophisticated tumor targeting algorithm and a volumetric magnetic resonance imaging (MRI) protocol.

Methods: At the time of submission, N = 10 patients with non-palpable T0 stage breast cancer have been treated with the breast MRgFUS system.

Technical Note: Effect of transducer position and ground plane configuration on image quality in MR-guided focused ultrasound therapies.

Purpose: To evaluate the effect of a focused ultrasound transducer position and ground plane configuration on magnetic resonance image quality.

Methods: The effect of transducer position with respect to the MRI B0 field and the radiofrequency receive coils was evaluated in a breast-specific MRgFUS system with an integrated RF phased-array coil. Image signal-to-noise ratio was evaluated at different transducer locations.

Effect of applied energy in renal sympathetic denervation with magnetic resonance guided focused ultrasound in a porcine model.

Background: Past catheter-based and focused ultrasound renal denervation studies have indicated that procedure efficacy is related to the number of ablations performed or the amount of energy used for the ablation. This study extends those prior results and investigates energy level effects on the efficacy of MR guided focused ultrasound renal denervation performed in a porcine model.

Methods: Twenty-four normotensive pigs underwent unilateral denervation at three intensity levels.

Renal sympathetic denervation using MR-guided high-intensity focused ultrasound in a porcine model.

Background: Initial catheter-based renal sympathetic denervation (RSD) studies demonstrated promising results in showing a significant reduction of blood pressure, while recent data were less successful. As an alternative approach, the objective of this study was to evaluate the feasibility of using magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) to perform RSD in a porcine model.

Methods: An intravascular fiber optic temperature probe was used to confirm energy delivery during MRgHIFU.

Sampling strategies for subsampled segmented EPI PRF thermometry in MR guided high intensity focused ultrasound.

Purpose: To investigate k-space subsampling strategies to achieve fast, large field-of-view (FOV) temperature monitoring using segmented echo planar imaging (EPI) proton resonance frequency shift thermometry for MR guided high intensity focused ultrasound (MRgHIFU) applications.

Methods: Five different k-space sampling approaches were investigated, varying sample spacing (equally vs nonequally spaced within the echo train), sampling density (variable sampling density in zero, one, and two dimensions), and utilizing sequential or centric sampling. Three of the schemes utilized sequential sampling with the sampling density varied in zero, one, and two dimensions, to investigate sampling the k-space center more frequently.

Reducing morphological variability of the cervical carotid artery in serial magnetic resonance imaging using a head and neck immobilization device.

Purpose: To evaluate how well a head and neck immobilization device performed in reducing lumen morphology variability in repeated MR imaging of the carotid artery.

Materials And Methods: Quantitative measures of lumen and plaque characteristics may be important for longitudinal management of carotid atherosclerotic disease. However, quantitative measurements of the carotid artery are limited by their dependence on patient positioning, which can be quite variable.