Magnetic resonance imaging-compatible tactile sensing device based on a piezoelectric array.

Minimally invasive surgery is a widely used medical technique, one of the drawbacks of which is the loss of direct sense of touch during the operation. Palpation is the use of fingertips to explore and make fast assessments of tissue morphology. Although technologies are developed to equip minimally invasive surgery tools with haptic feedback capabilities, the majority focus on tissue stiffness profiling and tool-tissue interaction force measurement.

Finite-element analysis for magnetic resonance image artifact evaluation.

The static magnetic field of a magnetic resonance imaging scanner can be distorted by the presence of materials, perturbing the spatial encoding process in magnetic resonance imaging and often resulting in image artifacts. The relationship between the image artifact size and magnetic susceptibility of the material specimen is of interest to engineers for the design of devices that are to be compatible with the imaging volume of the scanner. In this study, a finite-element method was used to simulate the distorted magnetic field of samples with different susceptibilities.

Piezoelectric actuator design for MR elastography: implementation and vibration issues.

Background: MR elastography (MRE) is an emerging technique for tumor diagnosis. MRE actuation devices require precise mechanical design and radiofrequency engineering to achieve the required mechanical vibration performance and MR compatibility.

Method: A method of designing a general-purpose, compact and inexpensive MRE actuator is presented.

Robotic system for transrectal biopsy of the prostate: real-time guidance under MRI.

In this paper, to harness the possibility of real-time guidance of MRI, a robotic system has been developed to perform transrectal prostate biopsy inside a 1.5-T closed bore scanner. A specially developed MR pulse sequence is capable of tracking the needle location in real time while dynamically updating the scan planes to always include the needle and target.

Manufacturing and placing a bespoke support for the Marfan aortic root: description of the method and technical results and status at one year for the first ten patients.

Fatal aortic dissection commonly occurs in Marfan syndrome. Prevention currently relies on elective replacement of the aortic root. We are evaluating the placement of a manufactured, bespoke external support derived from a computer aided design in a prospective study.

Sub-pixel localisation of passive micro-coil fiducial markers in interventional MRI.

Objective: Electromechanical devices enable increased accuracy in surgical procedures, and the recent development of MRI-compatible mechatronics permits the use of MRI for real-time image guidance. Integrated imaging of resonant micro-coil fiducials provides an accurate method of tracking devices in a scanner with increased flexibility compared to gradient tracking. Here we report on the ability of ten different image-processing algorithms to track micro-coil fiducials with sub-pixel accuracy.

The case for MR-compatible robotics: a review of the state of the art.

Background: The numerous imaging capabilities of magnetic resonance imaging (MRI) coupled with its lack of ionizing radiation has made it a desirable modality for real-time guidance of interventional procedures. The combination of these abilities with the advantages granted by robotic systems to perform accurate and precise positioning of tools has driven the recent development of MR-compatible interventional and assistive devices.

Methods: The challenges in this field are presented, including the selection of suitable materials, actuators and sensors in the intense magnetic fields of the MR environment.

A MR compatible mechatronic system to facilitate magic angle experiments in vivo.

When imaging tendons and cartilage in a MRI scanner, an increase in signal intensity is observed when they are oriented at 55 degrees with respect to Bo (the "magic angle"). There is a clear clinical importance for considering this effect as part of the diagnosis of orthopaedic and other injury. Experimental studies of this phenomenon have been made harder by practical difficulties of tissue positioning and orientation in the confined environment of cylindrical scanners.

The feasibility of MR-image guided prostate biopsy using piezoceramic motors inside or near to the magnet isocentre.

The excellent soft tissue contrast of Magnetic Resonance Imaging (MRI) has encouraged the development of MRI compatible systems capable of combining the advantages of robotic manipulators with high quality anatomical images. Continuing this development, a new five DOF prostate biopsy manipulator has been designed for use inside a closed 1.5T MRI scanner.