虚拟现实技术在神经外科术前计划中的应用

目的探讨虚拟现实（virtual reality，VR）技术在神经外科术前计划中的临床应用价值。方法对拟采用手术治疗的颅脑疾病26例，分别采集磁共振成像（MRI）、磁共振动脉成像（MRA）、磁共振静脉成像（MRV），计算机体层摄影（CT）等多种医学影像数据，输入Dextroscope术前计划系统，运用Radiodexter软件在VR环境中进行融合、提取、切割等处理显示为一个三维立体物像。同时运用软件内的三维处理工具对病灶及其局部解剖结构进行观察测量、手术模拟。制定术前计划，并与真正手术中情况进行对照比较。结果26例病例均成功地实现了三维立体虚拟现实影像的重建，术前计划中对于病灶及其局部解剖学特征的判定与术中实际情况吻合。结论Dextroscope系统的虚拟现实技术能快速、直观、全面地整合多种医学影像数据，以提供病灶及其局部解剖结构的综合信息，在神经外科手术前为制定和优化手术方案提供帮助，有可能有助于提高手术的安全性与病灶的全切除率。     

Realidad aumentada en cirugía hepato-bilio-pancreática. Una tecnología al alcance de la mano

Augmented reality is a technology that opens new possibilities in surgery. Its implementation in a hepatobiliary-pancreatic surgery unit is presented in relation to preoperative planning, intraoperative support and teaching.For surgical planning, 3D CT and MRI reconstructions have been used to evaluate complex cases, making the interpretation of the anatomy more precise and the planning of the technique simpler.At an intraoperative level, it has allowed remote holographic connection between specialists, the substitution of physical elements for virtual elements, and the use of virtual consultation models and surgical guides.In teaching, new lessons include the retransmission of a surgery with the support of virtual elements for a better understanding by the students.Being the experience satisfactory, augmented reality could be applied in the future of hepatobiliary-pancreatic surgery to improve its results.     

Stereoscopic navigation-controlled display of preoperative MRI and intraoperative 3D ultrasound in planning and guidance of neurosurgery: new technology for minimally invasive image-guided surgery approaches.

OBJECTIVE: This paper demonstrates a method that brings together three essential technologies for surgery planning and guidance: neuronavigation systems, 3D visualization techniques and intraoperative 3D imaging technologies. We demonstrate the practical use of an in-house interactive stereoscopic visualization module that is integrated with a 3D ultrasound based neuronavigation system. MATERIALS AND METHODS: A stereoscopy volume visualization module has been integrated with a 3D ultrasound based neuronavigation system, which also can read preoperative MR and CT data. The various stereoscopic display modalities, such as "cut plane visualization" and "interactive stereoscopic tool guidance" are controlled by a pointer, a surgical tool or an ultrasound probe. Interactive stereoscopy was tested in clinical feasibility case studies for planning and guidance of surgery procedures. RESULTS: By orientating the stereoscopic projections in accordance to the position of the patient on the operating table, it is easier to interpret complex 3D anatomy and to directly take advantage of this 3D information for planning and surgical guidance. In the clinical case studies, we experienced that the probe-controlled cut plane visualization was promising during tumor resection. By combining 2D and 3D display, interpretation of both detailed and geometric information may be achieved simultaneously. The possibilities of interactively guiding tools in a stereoscopic scene seemed to be a promising functionality for use during vascular surgery, due to specific location of certain vessels. CONCLUSION: Interactive stereoscopic visualization improves perception and enhances the ability to understand complex 3D anatomy. The practical benefit of 3D display is increased considerably when integrated with surgical navigation systems, since the orientation of the stereoscopic projection corresponds to the orientation of the patient on the operating table. Stereoscopic visualizations work well on MR and CT images, although volume rendering techniques are especially suitable for intraoperative 3D ultrasound image data.     

Surgical planning for microsurgical excision of cerebral arterio-venous malformations using virtual reality technology

Background  To evaluate the feasibility of surgical planning using a virtual reality platform workstation in the treatment of cerebral arterio-venous malformations (AVMs) Methods  Patient- specific data of multiple imaging modalities were co-registered, fused and displayed as a 3D stereoscopic object on the Dextroscope, a virtual reality surgical planning platform. This system allows for manipulation of 3D data and for the user to evaluate and appreciate the angio-architecture of the nidus with regards to position and spatial relationships of critical feeders and draining veins. We evaluated the ability of the Dextroscope to influence surgical planning by providing a better understanding of the angio-architecture as well as its impact on the surgeon’s pre- and intra-operative confidence and ability to tackle these lesions. Findings  Twenty four patients were studied. The mean age was 29.65 years. Following pre-surgical planning on the Dextroscope, 23 patients underwent microsurgical resection after pre-surgical virtual reality planning, during which all had documented complete resection of the AVM. Planning on the virtual reality platform allowed for identification of critical feeders and draining vessels in all patients. The appreciation of the complex patient specific angio-architecture to establish a surgical plan was found to be invaluable in the conduct of the procedure and was found to enhance the surgeon’s confidence significantly. Conclusion  Surgical planning of resection of an AVM with a virtual reality system allowed detailed and comprehensive analysis of 3D multi-modality imaging data and, in our experience, proved very helpful in establishing a good surgical strategy, enhancing intra-operative spatial orientation and increasing surgeon’s confidence.     

A three-dimensional interactive virtual dissection model to simulate transpetrous surgical avenues

OBJECTIVE: This project involves the development of a three-dimensional surgical simulator called interactive virtual dissection, which is designed to teach surgeons the visuospatial skills required to navigate through a transpetrosal approach. METHODS: A robotically controlled microscope is used for surgical planning and data collection. The spatial anatomic data are recorded from sequentially deeper cadaveric head dissections as a series of superimposed anatomic pictures in stereoscopic digital format. The sequential series of images are then merged to form the final virtual representation. RESULTS: The current three-dimensional virtual reality simulator allows the user to drill the petrous bone progressively deeper and to identify crucial structures much like an experienced surgeon drilling the petrous bone. The program allows surgeons and trainees to manipulate the virtual "surgical field" by interacting with the surgical anatomy. The interactive system functions on a desktop computer. CONCLUSION: The ability to visualize and understand anatomic spatial relationships is crucial in surgical planning, as is a surgeon's confidence in performing the surgery. The virtual reality simulator does not replace the need for practicing surgery on cadavers. However, it is designed to facilitate, via stereoscopic projection, learning how to manipulate a drill in complicated or unfamiliar surgical approaches (e.g., a transpetrosal approach).     

Interactive stereoscopic virtual reality: a new tool for neurosurgical education. Technical note.

The goal of this study was to develop a new method for neurosurgical education based on interactive stereoscopic virtual reality (ISVR). Interactive stereoscopic virtual reality can be used to recreate the three-dimensional (3D) experience of neurosurgical approaches much more realistically than standard educational methods. The demonstration of complex 3D relationships is unrivaled and easily combined with interactive learning and multimedia capabilities. Interactive stereoscopic virtual reality permits the accurate recreation of neurosurgical approaches through integration of several forms of stereoscopic multimedia (video, interactive anatomy, and computer-rendered animations). The content explored using ISVR is obtained through a combination of approach-based cadaver dissections, live surgical images and videos, and computer-rendered animations. These media are combined through an interactive software interface to demonstrate key aspects of a neurosurgical approach (for example, patient positioning, draping, incision, individual surgical steps, alternative steps, relevant anatomy). The ISVR platform is designed for use on a desktop personal computer with newly developed, inexpensive, platform-independent shutter glasses. Interactive stereoscopic virtual reality has been used to capture the anatomy and methods of several neurosurgical approaches. In this paper the authors report their experience with ISVR and describe its potential advantages. The success of a neurosurgical approach is contingent on the mastery of complex, 3D anatomy. A new technology for neurosurgical education, ISVR can improve understanding and speed the learning process. It is an effective tool for neurosurgical education, bridging the substantial gap between textbooks and intraoperative training.     

Imaging-assisted endoscopic surgery: Cleveland Clinic experience

BACKGROUND AND PURPOSE: Our initial experience in using computer-aided image assistance in minimally invasive urology was reported. MATERIALS AND METHODS: The system consisted of a computer and a localizer allowing spatial localization of the position of the various surgical instruments, using a magnetic sensor as well as an optical sensor. Available imaging modality included real-time ultrasound as well as preoperative computed tomography (CT) or magnetic resonance imaging (MRI). RESULTS: We first clinically applied the fusion system of real-time US with preoperative CT or MRI for percutanous radiofrequency/cryoablation for renal tumor. We also clinically applied an augmented reality visualization system that helps the laparoscopic surgeon to understand three-dimensional (3D) anatomies beyond the surgical view. Augmented reality was feasible and useful to facilitate the surgeon's direct interpretation of 3D anatomies of cancer or vital anatomies beyond the surgical view, using preoperative CT data during laparoscopic partial nephrectomy and intraoperative transrectal US during laparoscopic radical prostatectomy. To our knowledge, we report the first clinical use of augmented reality technology in urology. CONCLUSIONS: Imaging assistance beyond the endoscopic surgical view could increase the precision for and confidence of the surgeon, providing preoperative oncological data and understanding of the surrounding vital anatomies. Novel computer-based emerging techniques with 3D imaging technologies potentially indicate the ideal dissection plane to achieve better oncological outcomes as well as to maximize functional preservation.     

Virtual reality system for planning minimally invasive neurosurgery. Technical note

OBJECT: The authors report on their experience with a 3D virtual reality system for planning minimally invasive neurosurgical procedures. METHODS: Between October 2002 and April 2006, the authors used the Dextroscope (Volume Interactions, Ltd.) to plan neurosurgical procedures in 106 patients, including 100 with intracranial and 6 with spinal lesions. The planning was performed 1 to 3 days preoperatively, and in 12 cases, 3D prints of the planning procedure were taken into the operating room. A questionnaire was completed by the neurosurgeon after the planning procedure. RESULTS: After a short period of acclimatization, the system proved easy to operate and is currently used routinely for preoperative planning of difficult cases at the authors' institution. It was felt that working with a virtual reality multimodal model of the patient significantly improved surgical planning. The pathoanatomy in individual patients could easily be understood in great detail, enabling the authors to determine the surgical trajectory precisely and in the most minimally invasive way. CONCLUSIONS: The authors found the preoperative 3D model to be in high concordance with intraoperative conditions; the resulting intraoperative "déjà-vu" feeling enhanced surgical confidence. In all procedures planned with the Dextroscope, the chosen surgical strategy proved to be the correct choice. Three-dimensional virtual reality models of a patient allow quick and easy understanding of complex intracranial lesions.     

��ֱ������ת���и�ת�����г���ǰӰ��ѧ����

在过去20年,肝转移灶切除术逐渐成为改善转移性结肠癌病人预后的一种颇有前景的手段,在部分病例中,还提供了长期治愈的可能。为了使转移病灶切除术的安全性和疗效最大化,适宜的术前影像学检查必不可少。CT、MRI以及PET的发展不仅改善了对隐匿病灶的检出能力,同时也优化了解剖结构的定位。MRI在发现小于厘米级大小的肝转移病灶上更有优势。CT可作为一种筛检手段或在做术前计划中比较有用,例如估算残余肝脏容积或在术前为肝动脉灌注泵的安置确定动脉解剖位置。     

Preoperative imaging to predict orbital invasion by tumor

BACKGROUND: Our purpose was to examine the accuracy of preoperative imaging in assessing tumor invasion of the orbit and nasolacrimal system. METHODS: Nineteen preoperative CT and 17 preoperative MR images from patients at risk for orbital invasion were retrospectively reviewed. Invasion was corroborated by pathologic and intraoperative assessment. RESULTS: Tumor adjacent to the periorbita was the most sensitive predictor of orbital invasion (90%) for both CT and MRI. Extraocular muscle involvement on MRI (100%) and orbital fat obliteration (80% MRI, 86% CT) had the highest positive predictive values of the criteria evaluated. Extraocular muscle displacement and enhancement were less accurate (<65%) predictors. No one criterion was >79% accurate in predicting orbital invasion. Six or more positive criteria predicted invasion with 67% sensitivity and 80% specificity (accuracy, 72%). CT was more accurate than MRI in seven of nine criteria. Invasion of the nasolacrimal system was predicted accurately (89%). CONCLUSIONS: Although preoperative imaging can aid in surgical planning, it should not replace intraoperative assessment in ambiguous cases of orbital invasion.     

New imaging strategies for laparoscopic management of cancer

The Information Age has brought to the medical and surgical community the tools of digital imaging and 3-dimensional (3-D) visualization. These tools provide new methods for diagnosis and treatment of cancer. Using 3-D reconstructions from computed tomography and magnetic resonance imaging scans of patient-specific anatomy, diagnosis from virtual endoscopy is supplementing or replacing invasive endoscopic procedures. These same images can be used for preoperative planning of complicated procedures. At the time of surgery, data fusion of the real-time video image and the preoperative digital image provides intraoperative stereotactic navigation. These augmentations can be used in many types of procedures, from open and minimally invasive surgery to catheter-based and energy-directed therapies. This is a US government work. There are no restrictions on its use.     

Development and application of a virtual environment for reconstructive surgery.

OBJECTIVE: This paper details the development and application of a Virtual Environment for Reconstructive Surgery (VERS). It addresses the technical and user-interface challenges in developing such a system, and the lessons learned during application of the system in the case of a 17-year-old boy with a severe facial defect arising from the removal of a soft-tissue sarcoma. MATERIALS AND METHODS: Computed tomography (CT) scans were segmented into bone and soft-tissue classifications using traditional and novel algorithms, a surface mesh was generated, and imaging artifacts were removed, yielding a mesh suitable for visualization. This patient-specific mesh was then used in a virtual environment by the surgeons for preoperative visualization of the defect, planning of the surgery, and production of a custom surgical template to aid in repairing the defect. RESULTS: This system was successfully used to plan the surgery of the patient and to produce a custom, patient-specific template that was used to harvest bone from a donor site in order to reconstruct the defect. CONCLUSION: Despite technical challenges, virtual-environment surgical planning is useful as a clinical tool for preoperative visualization, cephalometric analysis, and surgical intervention. It can provide a more precise surgical result than would otherwise be realized using traditional methods.     

Image-based planning and validation of C1-C2 transarticular screw fixation using personalized drill guides.

OBJECTIVE: Posterior transarticular spine fusion is a surgical procedure used to stabilize the cervical bodies C1 and C2. Currently, spine screws are used most frequently, according to the procedure of Magerl. As the anatomy is rather complex and the view is limited, this procedure has a high risk factor. We present and validate a planning system for cervical screw insertion based on preoperative CT imaging. MATERIALS AND METHODS: The planning system discussed allowed a neurosurgeon to interactively determine the desired position of the cervical screws, based on appropriate and real-time reslices through the preoperative CT image volume. From the planning, a personalized mechanical drill guide was derived as a means of transferring the plan intraoperatively. Eight cadaver experiments were performed to validate this approach. Postoperative CT was applied, and screw locations were extracted from the postoperative images after registering them to preoperative images. In this way, the deviations of the axes of the planned and inserted screws were determined. RESULTS: From an initial cadaver series, it was observed that the drill guides were not stable enough to cope with the drilling forces, and tended to become displaced. Still, most of the inserted screws were reported to be placed adequately. No vascular compromise or invasion of the spinal canal was observed. For a second cadaver series, the design of the drill guide was altered. In this series, the displacement was no longer present, and all screws were optimally placed. CONCLUSIONS: The preoperative planning system allowed the neurosurgeon to rehearse screw insertion in a way that is closer to surgical reality. The image-based validation technique allowed verification and enhancement of the template design on a cadaver study, giving accuracies comparable to those obtained with transfer by navigation.     

Magnetic resonance imaging of the dysplastic renal moiety and ectopic ureter

PURPOSE: We determined the role of magnetic resonance imaging (MRI) in symptomatic children with clinically suspected and radiologically occult dysplastic renal moieties and ectopic ureters. MATERIALS AND METHODS: We reviewed clinical, imaging, cystoscopic, surgical and histological findings in 6 symptomatic children 1 to 15 years old with dysplastic renal moieties. RESULTS: After multiple conventional imaging studies failed to delineate urinary tract anatomy MRI provided detailed multiplanar images of dysplastic renal moieties that were diagnostic and predictive of subsequent intraoperative findings. Dysplastic upper pole moieties identified in 4 children were associated with ectopic ureters inserting into the vagina, prostatic urethra, bladder neck and bladder neck ureterocele in each. A solitary kidney with contralateral blind-ending ectopic ureters inserted into the bladder base in 2 cases. Pelvic cystic structures visualized by ultrasound in 3 patients were tortuous distal ureters on MRI. MRI specifically identified ureteral insertion sites that were not evident in 3 of the 5 patients who underwent cystoscopy. CONCLUSIONS: MRI may facilitate diagnosis, guide cystoscopy and aid in preoperative planning in children with poorly functioning renal moieties and ectopic ureters.     

比较研究几种影像学检查对颈椎病的术前评估价值

目的通过比较研究颈椎X线摄片、核磁共振（MRI）、脊髓造影螺旋CT重建几种影像学检查对颈椎病的诊断效能和术前评估价值。方法选择一组手术治疗的颈椎病患者术前分别行颈椎全套平片（包括正侧位、左右前斜45度位、侧位过伸过屈动态摄片）、脊髓造影螺旋CT扫描重建以及磁共振成像,三种影像检查结合临床表现分别对疾病进行病情评估和术前计划,结合手术所见比较这三种影像检查各自诊断效能和对手术的指导价值。结果颈椎全套平片总体上显示颈椎退变情况和骨性发育异常,动态摄片可判断颈椎不稳和动态狭窄因素;磁共振显示脊髓、硬膜囊受压及神经根受压表现,其独到之处能显示椎动脉血流异常及髓内病变;螺旋CT扫描示造影剂弥散均匀、显影满意,能显示硬膜囊、脊髓、神经根袖受压及椎间孔狭窄情况,并能判断压迫来源是骨性、软骨性还是软组织性,多维重建图像清晰、逼真,提供的影像信息更全面也更直观。结论（1）颈椎全套平片＋MRI检查基本满足颈椎病诊断和术前评估需要;（2）颈髓造影螺旋CT扫描重建能提供更多影像信息,显示颈椎各部位细微解剖结构,更有助于病情全面评估、指导术前计划,是颈椎病最有力的影像工具,可用于病情复杂的颈椎病的诊断和术前评估。     

Three-Dimensional Stereoscopic Volume Rendering of Malignant Pleural Mesothelioma

Our objective was to investigate the application of three-dimensional (3D) stereoscopic volume rendering with perceptual colorization on preoperative imaging for malignant pleural mesothelioma. At present, we have prospectively enrolled 6 patients being considered for resection of malignant pleural mesothelioma that have undergone a multidetector-row computed tomography (CT) scan of the chest. The CT data sets were volume rendered without preprocessing. The resultant 3D rendering was displayed stereoscopically and used to provide information regarding tumor extent, morphology, and anatomic involvement. To demonstrate this technique, this information was compared with the corresponding two-dimensional CT grayscale axial images from two of these patients. Three-dimensional stereoscopic reconstructions of the CT data sets provided detailed information regarding the local extent of tumor that could be used for preoperative surgical planning. Three-dimensional stereoscopic volume rendering for malignant pleural mesothelioma is a novel approach. Combined with our innovative perceptual colorization algorithm, stereoscopic volumetric analysis potentially allows for the accurate determination of the extent of pleural mesothelioma with results difficult to duplicate using grayscale, multiplanar CT images.     

Advanced neuronavigation in skull base tumors and vascular lesions.

OBJECTIVE: The purpose of this study was to describe the usefulness of recent advances of neuronavigational technology in the management of skull base tumors and of vascular lesions, treated via a skull base approach. METHODS: In 16 patients (skull base meningioma n = 9, petrous apex epidermoid n = l, craniopharyngeoma n = 1, giant internal carotid artery aneurysm n = 1, basilar/vertebral artery aneurysm n = 2, brain stem cavernoma n = 2), "advanced" neuronavigation was used. In contrast to "conventional" neuronavigation, the information for the neurosurgeon was enhanced by the intraoperative screen display of 3-dimensional reconstructions of the lesion, vessels, nerves and fiber tracts at risk. The 3-dimensional reconstructions were obtained by preoperative manual or automated segmentation processes. In addition, different imaging modalities (computed tomography [CT] with magnetic resonance imaging [MRI], CT with CT angiography, T (l)- with diffusion-weighted MRI) were fused and shown on the screen. RESULTS: In the cases of tumors, "advanced" neuronavigation facilitated the approach (n = 4), contributed to tailor the approach (n = 2) and helped to identify hidden neurovascular structures (n = 9). In the cases of aneurysms, "advanced" neuronavigation allowed us to reduce the skull base approach to the needs of safe aneurysm clipping (n = 3). In both cases of brain stem cavernoma, "advanced" neuronavigation was deemed useful for definition of the best surgical approach in relation to the pyramidal tract and brain stem nuclei. CONCLUSION: The authors' experiences suggest that neuronavigation, which displays 3-dimensional reconstructions of lesion, vessels, nerves and fiber tracts during surgery and makes use of image fusion techniques, is an important tool in the neurosurgical management of skull base lesions.     

3D虚拟手术规划系统在精准肝切除治疗肝细胞癌中的临床应用

目的 探讨3D虚拟手术规划技术对精准肝切除治疗肝细胞癌的指导价值.方法 回顾性分析16例肝细胞癌患者通过3D虚拟手术规划系统（IQQA-Liver）辅助下进行肝切除的临床资料,术前使用IQQA-Liver对患者薄层CT图像进行三维重建,对病灶定位和分割,评估病灶与肝内管道等信息,并分别计算标准肝脏体积、肿瘤体积、预切除肝脏体积、剩余肝脏体积和残肝体积百分比,从3D影像学角度完成术前评估和手术方案设计,制定个体化手术方案,并与术后实际切除肝脏体积进行比较.结果 使用IQQA-Liver对肝脏进行三维重建的模型结构清晰、直观、形象逼真.所有手术患者术后残肝体积均能得到准确评估,确保代偿,住院天数4～11 d（平均7d）,未出现肝衰及胆漏等并发症,住院期间无死亡病例,16例患者模拟手术预切除体积与实际手术切除的肝脏体积具有明显相关性,平均误差率约6.3％.结论 IQQA-Liver可在术前准确模拟肝脏切除手术情况,对制定精准肝切除手术方案有指导作用.     

Scimitar syndrome; report of a case

A 17-year-old woman with scimitar syndrome without an atrial septal defect was operated by intra-cardiac conduit repair. Computed tomography (CT) and magnetic resonance imaging (MRI) showed resolution images of anatomical findings of scimitar vein. Surgical procedures for the scimitar syndrome have varied according to the anatomic features presented in each case. The detection of precise anatomy of scimitar syndrome is important for determining the appropriate surgical procedure. Images of 3-dimensional (3-D) CT and MRI of scimitar syndrome were demonstrated.