A Vector Flow Imaging Method for Portable Ultrasound Using Synthetic Aperture Sequential Beamforming.

This paper presents a vector flow imaging method for the integration of quantitative blood flow imaging in portable ultrasound systems. The method combines directional transverse oscillation (TO) and synthetic aperture sequential beamforming to yield continuous velocity estimation in the whole imaging region. Six focused emissions are used to create a high-resolution image (HRI), and a dual-stage beamforming approach is used to lower the data throughput between the probe and the processing unit.

Quantitative Neuroimaging Software for Clinical Assessment of Hippocampal Volumes on MR Imaging.

Background: Multiple neurological disorders including Alzheimer's disease (AD), mesial temporal sclerosis, and mild traumatic brain injury manifest with volume loss on brain MRI. Subtle volume loss is particularly seen early in AD. While prior research has demonstrated the value of this additional information from quantitative neuroimaging, very few applications have been approved for clinical use.

The visible ear simulator: a public PC application for GPU-accelerated haptic 3D simulation of ear surgery based on the visible ear data.

Background: Existing virtual simulators for middle ear surgery are based on 3-dimensional (3D) models from computed tomographic or magnetic resonance imaging data in which image quality is limited by the lack of detail (maximum, approximately 50 voxels/mm3), natural color, and texture of the source material.Virtual training often requires the purchase of a program, a customized computer, and expensive peripherals dedicated exclusively to this purpose.

Materials And Methods: The Visible Ear freeware library of digital images from a fresh-frozen human temporal bone was segmented, and real-time volume rendered as a 3D model of high-fidelity, true color, and great anatomic detail and realism of the surgically relevant structures.

Developing and evaluating virtual cardiotomy for preoperative planning in congenital heart disease.

Careful preoperative planning is of outmost importance - in particular when considering complex corrective surgery on congenitally malformed hearts. As an aid to such decision-making we describe a system for virtual reconstruction of patient-specific morphology from 3D-capable imaging modalities such as MRI and CT. We introduce and illustrate the concept of virtual cardiotomy as a new tool to preoperatively evaluate the feasibility of different surgical strategies by investigating the anatomical spatial relations through any number of virtual incisions.

Virtual cardiotomy based on 3-D MRI for preoperative planning in congenital heart disease.

Background: Patient-specific preoperative planning in complex congenital heart disease may be greatly facilitated by virtual cardiotomy. Surgeons can perform an unlimited number of surgical incisions on a virtual 3-D reconstruction to evaluate the feasibility of different surgical strategies.

Objective: To quantitatively evaluate the quality of the underlying imaging data and the accuracy of the corresponding segmentation, and to qualitatively evaluate the feasibility of virtual cardiotomy.

The visible ear surgery simulator.

This paper presents a real-time computer simulation of surgical procedures in the ear, in which a surgeon drills into the temporal bone to gain access to the middle or inner ear. The purpose of this simulator is to support development of anatomical insight and training of drilling skills for both medical students and experienced otologists. The key contributions in this application are the visualization and interaction models in the context of ear surgical simulation.

A framework for shape matching in deformable image registration.

Many existing image registration methods have difficulties in accurately describing significant rotation and bending of entities (e.g. organs) between two datasets.

Surgical simulation--a new tool to evaluate surgical incisions in congenital heart disease?

We introduce a new concept for preoperative planning and surgical education in congenital heart disease: surgical simulation. Recent advances in three-dimensional image acquisition have provided a new means to virtually reconstruct accurate morphological models while computer visualisation hardware now allows simulation of elastic tissue deformations interactively. Incision simulation is performed in two patients with complex congenital heart disease to preoperatively evaluate potential corrective surgical strategies.

Virtual open heart surgery segmentation.

We have developed a semi-automated segmentation method based on the Watershed transform [1]. The watershed transform is a fast and intuitive segmentation method. It is applied to 3D cardiac MRI to interactively produce patient-specific models for pre-operative planning and virtual heart surgery [2].

Virtual open heart surgery: obtaining models suitable for surgical simulation.

We present a pre-processing strategy including imaging, segmentation, and model reconstruction that is well suited for previously published GPU-accelerated techniques for surgical simulation. In particular we describe these modeling steps as a prerequisite for our virtual open heart surgery simulator. A short description including relevant references is presented for each of the steps.

Smooth haptic interaction from discontinuous simulation data.

When a physical simulation that relies on haptic interaction is temporarily paused due to e.g. visualization, noticeable discontinuities are introduced in the interaction as well as the haptic-feedback.

Haptic feedback for the GPU-based surgical simulator.

The GPU has proven to be a powerful processor to compute spring-mass based surgical simulations. It has not previously been shown however, how to effectively implement haptic interaction with a simulation running entirely on the GPU. This paper describes a method to calculate haptic feedback with limited performance cost.

A GPU accelerated spring mass system for surgical simulation.

There is a growing demand for surgical simulators to do fast and precise calculations of tissue deformation to simulate increasingly complex morphology in real-time. Unfortunately, even fast spring-mass based systems have slow convergence rates for large models. This paper presents a method to accelerate computation of a spring-mass system in order to simulate a complex organ such as the heart.

LR-Spring Mass model for cardiac surgical simulation.

The purpose of the research conducted was to develop a real-time surgical simulator for preoperative planning of surgery in congenital heart disease. The main problem simulating procedures on cardiac morphology is the need for a large degree of detail and simulation speed. In combination with a demand for physically realistic real-time behaviour this gives us tradeoffs not easily balanced.

Parameter optimisation for the behaviour of elastic models over time.

Optimisation of parameters for elastic models is essential for comparison or finding equivalent behaviour of elastic models when parameters cannot simply be transferred or converted. This is the case with a large range of commonly used elastic models. In this paper we present a general method that will optimise parameters based on the behaviour of the elastic models over time.