The EASI project-improving the effectiveness and quality ofimage-guided surgery

In recent years, advances in computer technology and a significant increase in the accuracy of medical imaging have made it possible to develop systems that can assist the clinician in diagnosis, planning, and treatment. This paper deals with an area that is generally referred to as computer-assisted surgery, image-directed surgery, or image-guided surgery. We report the research, development, and clinical validation performed since January 1996 in the European Applications in Surgical Interventions (EASI) project, which is funded by the European Commission in their “4th Framework Telematics Applications for Health” program. The goal of this project is the improvement of the effectiveness and quality of image-guided neurosurgery of the brain and image-guided vascular surgery of abdominal aortic aneurysms, while at the same time reducing patient risks and overall cost. We have developed advanced prototype systems for preoperative surgical planning and intraoperative surgical navigation, and we have extensively clinically validated these systems. The prototype systems and the clinical validation results are described in this paper     

CVD-HNet: Classifying Pneumonia and COVID-19 in Chest X-ray Images Using Deep Network

Wireless Personal Communications - The use of computer-assisted analysis to improve image interpretation has been a long-standing challenge in the medical imaging industry. In terms of image...     

Compensation of sound speed deviations in 3-D B-mode ultrasound for intraoperative determination of the anterior pelvic plane

An accurate determination of the pelvic orientation is inevitable for the correct cup prosthesis placement of navigated total hip arthroplasties. Conventionally, this step is accomplished by percutaneous palpation of anatomic landmarks. Sterility issues and an increased landmark localization error for obese patients lead to the application of B-mode ultrasound imaging in the field of computer-assisted orthopedic surgery. Many approaches have been proposed in the literature to replace the percutaneous digitization by 3-D B-mode ultrasound imaging. However, the correct depth localization of the pelvic landmarks could be significantly affected by the acoustic properties of the penetrated tissues. Imprecise depth estimation could lead to a miscalculation of the pelvic orientation and subsequently to a misalignment of the acetabular cup implant. But so far, no solution has been presented, which compensates for acoustic property differences for correct depth estimation. In this paper, we present a novel approach to determine pelvic orientation from ultrasound images by applying a hierarchical registration scheme based on patch statistical shape models to compensate for differences in speed of sound. The method was validated based on plastic bones and a cadaveric specimen.     

Intelligent computer-aided instruction for training in telecommunications

Intelligent computer-aided instruction (ICAI) involves applying artificial intelligence techniques to computer-assisted instruction. ICAI allows for more directed questioning and informative answering for the trainee or student than the question-answer strategies employed by conventional computer-assisted instruction. ICAI has been applied to several areas of discipline, but has not yet penetrated the telecommunications domain. This article surveys the ICAI programs that have been built, and then explains the need for and gives examples of potential areas for ICAI development for training in telecommunications.     

Accurate localization of optic radiation during neurosurgery in an interventional MRI suite

Accurate localization of the optic radiation is key to improving the surgical outcome for patients undergoing anterior temporal lobe resection for the treatment of refractory focal epilepsy. Current commercial interventional magnetic resonance imaging (MRI) scanners are capable of performing anatomical and diffusion weighted imaging and are used for guidance during various neurosurgical procedures. We present an interventional imaging workflow that can accurately localize the optic radiation during surgery. The workflow is driven by a near real-time multichannel nonrigid image registration algorithm that uses both anatomical and fractional anisotropy pre- and intra-operative images. The proposed workflow is implemented on graphical processing units and we perform a warping of the pre-operatively parcellated optic radiation to the intra-operative space in under 3 min making the proposed algorithm suitable for use under the stringent time constraints of neurosurgical procedures. The method was validated using both a numerical phantom and clinical data using pre- and post-operative images from patients who had undergone surgery for treatment of refractory focal epilepsy and shows strong correlation between the observed post-operative visual field deficit and the predicted damage to the optic radiation. We also validate the algorithm using interventional MRI datasets from a small cohort of patients. This work could be of significant utility in image guided interventions and facilitate effective surgical treatments.     

机载双天线斜视干涉SAR自配准成像方法研究

本文针对机载双天线斜视干涉SAR成像过程分析了主辅天线回波信号距离历程偏移特性、方位多普勒频率特性及其与正侧视系统下的区别;讨论了基于扩展CS算法 (ECS算法)距离向自配准成像过程中距离向平移因子和缩放因子;推导了距离向自配准成像处理的基本公式和具体实现过程。通过计算机仿真实现了机载双天线斜视干涉SAR系统在成像处理阶段实现距离向高精度的自配准的过程。通过对配准前后主辅图像相关特性、干涉相位纹图质量以及配准误差的分析,验证了推导过程的正确性和该算法的有效性。      

Modern microwave: inverse-scattering techniques for imagereconstruction

The development of efficient reconstruction procedures is of fundamental importance in microwave imaging applications. A great deal of research has been devoted to the study of optimization techniques based on space-domain formulations for which deterministic or stochastic methodologies are applied. In parallel, strong efforts are also underway to develop effective and accurate illuminating and measurement systems. It should be noted that microwave imaging techniques may be used in a complementary fashion or integrated with other more standard imaging techniques. The data fusion performed should provide a much more comprehensive inspection than any one technique could provide on its own     

Automated Retinal Image Analysis Over the Internet

Retinal clinicians and researchers make extensive use of images, and the current emphasis is on digital imaging of the retinal fundus. The goal of this paper is to introduce a system, known as retinal image vessel extraction and registration system, which provides the community of retinal clinicians, researchers, and study directors an integrated suite of advanced digital retinal image analysis tools over the Internet. The capabilities include vasculature tracing and morphometry, joint (simultaneous) montaging of multiple retinal fields, cross-modality registration (color/red-free fundus photographs and fluorescein angiograms), and generation of flicker animations for visualization of changes from longitudinal image sequences. Each capability has been carefully validated in our previous research work. The integrated Internet-based system can enable significant advances in retina-related clinical diagnosis, visualization of the complete fundus at full resolution from multiple low-angle views, analysis of longitudinal changes, research on the retinal vasculature, and objective, quantitative computer-assisted scoring of clinical trials imagery. It could pave the way for future screening services from optometry facilities.     

Technology improvements for image-guided and minimally invasive spine procedures

This paper reports on technology developments aimed at improving the state of the art for image-guided minimally invasive spine procedures. Back pain is a major health problem with serious economic consequences. Minimally invasive procedures to treat back pain are rapidly growing in popularity due to improvements in technique and the substantially reduced trauma to the patient versus open spinal surgery. Image guidance is an enabling technology for minimally invasive procedures, but technical problems remain that may limit the wider applicability of these techniques. The paper begins with a discussion of low back pain and the potential shortcomings of open back surgery. The advantages of minimally invasive procedures are enumerated, followed by a list of technical problems that must be overcome to enable the more widespread dissemination of these techniques. The technical problems include improved intraoperative imaging, fusion of images from multiple modalities, the visualization of oblique paths, percutaneous spine tracking, mechanical instrument guidance, and software architectures for technology integration. Technical developments to address some of these problems are discussed next. The discussion includes intraoperative computerized tomography (CT) imaging, magnetic resonance imaging (MRI)/CT image registration, three-dimensional (3-D) visualization, optical localization, and robotics for percutaneous instrument placement. Finally, the paper concludes by presenting several representative clinical applications: biopsy, vertebroplasty, nerve and facet blocks, and shunt placement. The program presented here is a first step to developing the physician-assist systems of the future, which will incorporate visualization, tracking, and robotics to enable the precision placement and manipulation of instruments with minimal trauma to the patient.     

Head‐Mounted Devices for Noninvasive Cancer Imaging and Intraoperative Image‐Guided Surgery

Medical imaging methods have improved the detection of human diseases with increasing accuracy. The ability to probe molecular processes noninvasively or using tissue‐selective imaging agents and nanoparticles has made it possible to localize, identify the stage, and determine the functional status of pathological lesions. The challenges in detecting cancer particularly have driven the development of diverse imaging technologies. While earlier cancer imaging methods enabled preoperative evaluation, the need to track and visualize cancer location in the operating room itself has ushered in new systems capable of providing concurrent images of cancer during surgery. Intraoperative use of conventional clinical imaging modalities is often limited by bulky hardware design, prohibitive cost, lack of real‐time image display, and compatibility with conventional hardware interfaces. For these reasons, focus on fluorescence‐guided surgery (FGS) devices has increased to take advantage of real‐time, high‐resolution, functional imaging with hardware that has become increasingly amenable to miniaturization. In particular, the adaptation of wearable devices for FGS presents hands‐free capability for optimal navigation during cancer surgery. The evolution of head‐mounted devices in the operating room and adaptation for FGS is highlighted. Key challenges to wide clinical adoption of this imaging platform are identified and potential future directions are suggested.     

Three-dimensional multimodal image-guidance for neurosurgery

The authors address the use of multimodality imaging as an aid to the planning and guidance of neurosurgical procedures, and discuss the integration of anatomical (CT and MRI), vascular (DSA), and functional (PET) data for presentation to the surgeon during surgery. The authors' workstation is an enhancement of a commercially available system, and in addition to the guidance offered via a hand-held probe, it incorporates the use of multimodality imaging and adds enhanced realism to the surgeon through the use of a stereoscopic three-dimensional (3-D) image display. The probe may be visualized stereoscopically in single or multimodality images. The integration of multimodality data in this manner provides the surgeon with a complete overview of brain structures on which he is performing surgery, or through which he is passing probes or cannulas, enabling him to avoid critical vessels and/or structures of functional significance.     

An MRI-compatible endonasal surgical robotic system: Kinematic analysis and performance evaluation

Neurosurgical interventions are often complicated and require procedure-specific solutions for a better outcome. A pituitary tumor is one of the common brain tumors resected by trans-sphenoidal surgery. Magnetic resonance imaging (MRI) provides better vision when compared to other imaging modalities. Simultaneous resection and imaging of pituitary tumors under MRI can improve the surgical outcome. Herein, we propose the first MRI-compatible robotic system for pituitary tumor removal via trans-sphenoidal/endonasal access. The presented system follows the current gold standard procedure of pituitary tumor resection and integrates it with a commercial MR scanner to provide a widely applicable system. The robotic system is the procedure-, anatomy-, and geometry-specific with 6-degree-of-freedom actuated by a bed-type actuation platform in the MRI room. A K-means clustering algorithm detects the tumor and develops and updates the brain model periodically during MR-guided interventions. The robot has procedure-specific stiffness changing capability with a unique stiffness-dependent kinematic model. The workspace subtended by the robotic system in all stiffness cases satisfies the workspace required for surgical procedures. The accuracy and repeatability of the robot are also in a desirable range. The procedure and patient-specific robot design are evaluated by in-vivo experiments in the live porcine under MRI. This work is a step toward a dual-arm surgical system for pituitary tumor removal under MRI guidance and experimental results validate the proposed solution and supplement further development to achieve a clinically applicable system.     

A system for real-time XMR guided cardiovascular intervention

The hybrid magnetic resonance (MR)/X-ray suite (XMR) is a recently introduced imaging solution that provides new possibilities for guidance of cardiovascular catheterization procedures. We have previously described and validated a technique based on optical tracking to register MR and X-ray images obtained from the sliding table XMR configuration. The aim of our recent work was to extend our technique by providing an improved calibration stage, real-time guidance during cardiovascular catheterization procedures, and further off-line analysis for mapping cardiac electrical data to patient anatomy. Specially designed optical trackers and a dedicated calibration object have resulted in a single calibration step that can be efficiently checked and updated before each procedure. An X-ray distortion model has been implemented that allows for distortion correction for arbitrary c-arm orientations. During procedures, the guidance system provides a real-time combined MR/X-ray image display consisting of live X-ray images with registered recently acquired MR derived anatomy. It is also possible to reconstruct the location of catheters seen during X-ray imaging in the MR derived patient anatomy. We have applied our registration technique to 13 cardiovascular catheterization procedures. Our system has been used for the real-time guidance of ten radiofrequency ablations and one aortic stent implantation. We demonstrate the real-time guidance using two exemplar cases. In a further two cases we show how off-line analysis of registered image data, acquired during electrophysiology study procedures, has been used to map cardiac electrical measurements to patient anatomy for two different types of mapping catheters. The cardiologists that have used the guidance system suggest that real-time XMR guidance could have substantial value in difficult interventional and electrophysiological procedures, potentially reducing procedure time and delivered radiation dose. Also, the ability to map measured electrical data to patient specific anatomy provides improved visualization and a path to investigation of cardiac electromechanical models.     

A computer-assisted training/monitoring system for TURP structureand design

A generic framework for a computer-assisted system for both soft tissue endoscopic surgery and surgical training is being researched and developed. The concept demonstrator is a specific system for transurethral prostatic resection (TURF). The main novelty of the research is that it is not confined to an in vitro trainer system. An in vivo monitoring version of the system, for use in the operating theater, is also being researched. This paper presents the framework's structure and design using the Unified Modeling Language. It also discusses and justifies the underlying information technologies chosen to implement this approach. Object-oriented concepts and well-proven mathematical tools have been adopted as the foundation of this research and development. The rationale for having chosen such tools is presented. The objectives are to arrive at a system which is modular, general, and reusable     

Tumor‐Targeted Multimodal Optical Imaging with Versatile Cadmium‐Free Quantum Dots

The rapid development of fluorescence imaging technologies requires concurrent improvements in the performance of fluorescent probes. Quantum dots have been extensively used as an imaging probe in various research areas because of their inherent advantages based on unique optical and electronic properties. However, their clinical translation has been limited by the potential toxicity especially from cadmium. Here, a versatile bioimaging probe is developed by using highly luminescent cadmium‐free CuInSe₂/ZnS core/shell quantum dots conjugated with CGKRK (Cys–Gly–Lys–Arg–Lys) tumor‐targeting peptides. This probe exhibits excellent photostability, reasonably long circulation time, minimal toxicity, and strong tumor‐specific homing property. The most important feature of this probe is that it shows distinctive versatility in tumor‐targeted multimodal imaging including near‐infrared, time‐gated, and two‐photon imaging in different tumor models. In a glioblastoma mouse model, the targeted probe clearly denotes tumor boundaries and positively labels a population of diffusely infiltrating tumor cells, suggesting its utility in precise tumor detection during surgery. This work lays a foundation for potential clinical translation of the probe.     

Fiducial optimization for minimal target registration error in image-guided neurosurgery

This paper presents new methods for the optimal selection of anatomical landmarks and optimal placement of fiducial markers in image-guided neurosurgery. These methods allow the surgeon to optimally plan fiducial marker locations on routine diagnostic images before preoperative imaging and to intraoperatively select the set of fiducial markers and anatomical landmarks that minimize the expected target registration error (TRE). The optimization relies on a novel empirical simulation-based TRE estimation method built on actual fiducial localization error (FLE) data. Our methods take the guesswork out of the registration process and can reduce localization error without additional imaging and hardware. Our clinical experiments on five patients who underwent brain surgery with a navigation system show that optimizing one marker location and the anatomical landmarks configuration reduced the TRE. The average TRE values using the usual fiducials setup and using the suggested method were 4.7 mm and 3.2 mm, respectively. We observed a maximum improvement of 4 mm. Reducing the target registration error has the potential to support safer and more accurate minimally invasive neurosurgical procedures.     

微波光子成像雷达技术发展综述

随着隐身化、无人化以及微型集群化目标的快速发展,精确获取目标形状和形态的情报需求,对微波成像雷达提出了大带宽和多频段的现实要求。得益于微波光子技术的低相噪、大带宽、宽调谐等显著优势,微波光子成像雷达技术已得到快速发展。本文对微波光子成像雷达研究现状进行了总结,对其典型系统架构和主要工作原理进行了研究分析,进一步结合系统能力优势给出了主要应用方向和相关成像实验结果,最后提出了进一步发展仍需解决的问题。     

Rapid automated tracing and feature extraction from retinal fundus images using direct exploratory algorithms

Algorithms are presented for rapid, automatic, robust, adaptive, and accurate tracing of retinal vasculature and analysis of intersections and crossovers. This method improves upon prior work in several ways: automatic adaptation from frame to frame without manual initialization/adjustment, with few tunable parameters; robust operation on image sequences exhibiting natural variability, poor and varying imaging conditions, including over/under-exposure, low contrast, and artifacts such as glare; does not require the vasculature to be connected, so it can handle partial views; and operation is efficient enough for use on unspecialized hardware, and amenable to deadline-driven computing, being able to produce a rapidly and monotonically improving sequence of usable partial results. Increased computation can be traded for superior tracing performance. Its efficiency comes from direct processing on gray-level data without any preprocessing, and from processing only a minimally necessary fraction of pixels in an exploratory manner, avoiding low-level image-wide operations such as thresholding, edge detection, and morphological processing. These properties make the algorithm suited to real-time, on-line (live) processing and is being applied to computer-assisted laser retinal surgery.     

Miniature in vivo robots for remote and harsh environments

Long-term human space exploration will require contingencies for emergency medical procedures including some capability to perform surgery. The ability to perform minimally invasive surgery (MIS) would be an important capability. The use of small incisions reduces surgical risk, but also eliminates the ability of the surgeon to view and touch the surgical environment directly. Robotic surgery, or telerobotic surgery, may provide emergency surgical care in remote or harsh environments such as space flight, or extremely forward environments such as battlefields. However, because current surgical robots are large and require extensive support personnel, their implementation has remained limited in forward environments, and they would be difficult, or impossible, to use in space flight or on battlefields. This paper presents experimental analysis of miniature fixed-base and mobile in vivo robots to support MIS surgery in remote and harsh environments. The objective is to develop wireless imaging and task-assisting robots that can be placed inside the abdominal cavity during surgery. Such robots will provide surgical task assistance and enable an on-site or remote surgeon to view the surgical environment from multiple angles. This approach is applicable to long-duration space flight, battlefield situations, and for traditional medical centers and other remote surgical locations.     

Miniature in vivo Robots for Remote and Harsh Environments

Long-term human space exploration will require contingencies for emergency medical procedures including some capability to perform surgery. The ability to perform minimally invasive surgery (MIS) would be an important capability. The use of small incisions reduces surgical risk, but also eliminates the ability of the surgeon to view and touch the surgical environment directly. Robotic surgery, or telerobotic surgery, may provide emergency surgical care in remote or harsh environments such as space flight, or extremely forward environments such as battlefields. However, because current surgical robots are large and require extensive support personnel, their implementation has remained limited in forward environments, and they would be difficult, or impossible, to use in space flight or on battlefields. This paper presents experimental analysis of miniature fixed-base and mobile in vivo robots to support MIS surgery in remote and harsh environments. The objective is to develop wireless imaging and task-assisting robots that can be placed inside the abdominal cavity during surgery. Such robots will provide surgical task assistance and enable an on-site or remote surgeon to view the surgical environment from multiple angles. This approach is applicable to long-duration space flight, battlefield situations, and for traditional medical centers and other remote surgical locations.