A new device for fiducial registration of image-guided navigation system for liver RFA

Purpose

Radiofrequency ablation for liver tumors (liver RFA) is widely performed under ultrasound guidance. However, discriminating between the tumor and the needle is often difficult because of cavitation caused by RFA-induced coagulation. An unclear ultrasound image can lead to complications and tumor residue. Therefore, image-guided navigation systems based on fiducial registration have been developed. Fiducial points are usually set on a patient’s skin. But the use of internal fiducial points can improve the accuracy of navigation. In this study, a new device is introduced to use internal fiducial points using 2D US.

Methods

3D Slicer as the navigation software, Polaris Vicra as the position sensor, and two target tumors in a 3D abdominal phantom as puncture targets were used. Also, a new device that makes it possible to obtain tracking coordinates in the body was invented. First, two-dimensional reslice images from the CT images using 3D Slicer were built. A virtual needle was displayed on the two-dimensional reslice image, reflecting the movement of the actual needle after fiducial registration. A phantom experiment using three sets of fiducial point configurations: one conventional case using only surface points, and two cases in which the center of the target tumor was selected as a fiducial point was performed. For each configuration, one surgeon punctured each target tumor ten times under guidance from the 3D Slicer display. Finally, a statistical analysis examining the puncture error was performed.

Results

The puncture error for each target tumor decreased significantly when the center of the target tumor was included as one of the fiducial points, compared with when only surface points were used.

Conclusion

This study introduces a new device to use internal fiducial points and suggests that the accuracy of image-guided navigation systems for liver RFA can be improved by using the new device.

     

Retroviral gene transfer to primitive normal and leukemic hematopoietic cells using clinically applicable procedures.

Clinical uses of gene transfer to bone marrow transplants require the establishment of a reproducible method for infecting large numbers of very primitive hematopoietic cells at high efficiency using cell-free retrovirus-containing media. In this study we report the results of experiments with preparations of a high-titer (2-5 x 10(7)/ml) helper-free recombinant neo(r) retrovirus that indicate this goal can now be achieved based on measurements of gene transfer efficiencies to cells referred to as long-term culture initiating cells (LTC-IC) because they give rise to clonogenic cells after greater than or equal to 5 wk in long-term culture (LTC). Intermittent, repeated exposure of normal human marrow mononuclear cells to virus-containing supernatant over a 3-d period of cell maintenance on an IL-3/granulocyte colony-stimulating factor (G-CSF) producing stromal layer resulted in gene transfer efficiencies to LTC-IC of 41%; a level previously obtainable only using co-cultivation infection techniques. Marrow cells enriched greater than or equal to 500-fold for LTC-IC (1-2% pure) by flow cytometry showed gene transfer efficiencies of 27% when infected in a similar fashion over a shorter period (24 h), but in the presence of added soluble IL-3 and G-CSF without stromal feeders, and this increased to 61% when Steel factor was also present during the infection period. By using a less highly enriched population of LTC-IC obtained by a bulk immunoselection technique applicable to large-scale clinical marrow harvests, gene transfer efficiencies to LTC-IC of 40% were achieved and this was increased to 60% by short-term preselection in G418. Southern analysis of DNA from the nonadherent cells produced by these LTC over a 6-wk period provided evidence of clonal evolution of LTC-IC in vitro. Leukemic chronic myelogenous leukemia LTC-IC were also infected at high efficiency using the same supernatant infection strategy with growth factor supplementation. These data demonstrate the feasibility of using cell-free virus preparations for infecting clinical marrow samples suitable for transplantation, as well as for further analysis of human marrow stem cell dynamics in vitro.     

A subject-specific technique for respiratory motion correction in image-guided cardiac catheterisation procedures

We describe a system for respiratory motion correction of MRI-derived roadmaps for use in X-ray guided cardiac catheterisation procedures. The technique uses a subject-specific affine motion model that is quickly constructed from a short pre-procedure MRI scan. We test a dynamic MRI sequence that acquires a small number of high resolution slices, rather than a single low resolution volume. Additionally, we use prior knowledge of the nature of cardiac respiratory motion by constraining the model to use only the dominant modes of motion. During the procedure the motion of the diaphragm is tracked in X-ray fluoroscopy images, allowing the roadmap to be updated using the motion model. X-ray image acquisition is cardiac gated. Validation is performed on four volunteer datasets and three patient datasets. The accuracy of the model in 3D was within 5 mm in 97.6% of volunteer validations. For the patients, 2D accuracy was improved from 5 to 13 mm before applying the model to 2–4 mm afterwards. For the dynamic MRI sequence comparison, the highest errors were found when using the low resolution volume sequence with an unconstrained model.     

Development of a clinically applicable tool for bone density assessment

Objectives

To assess the accuracy and reliability of new software for radiodensitometric evaluations.

Methods

A densitometric tool developed by MevisLab^® was used in conjunction with intraoral radiographs of the premolar region in both in vivo and laboratory settings. An aluminum step wedge was utilized for comparison of grey values. After computer-aided segmentation, the interproximal bone between the premolars was assessed in order to determine the mean grey value intensity of this region and convert it to a thickness in aluminum. Evaluation of the tool was determined using bone mineral density (BMD) values derived from decalcified human bone specimens as a reference standard. In vivo BMD data was collected from 35 patients as determined with dual X-ray absorptiometry (DXA). The intra and interobserver reliability of this method was assessed by Bland and Altman Plots to determine the precision of this tool.

Results

In the laboratory study, the threshold value for detection of bone loss was 6.5%. The densitometric data (mm Al eq.) was highly correlated with the jaw bone BMD, as determined using dual X-ray absorptiometry (r = 0.96). For the in vivo study, the correlations between the mm Al equivalent of the average upper and lower jaw with the lumbar spine BMD, total hip BMD and femoral neck BMD were 0.489, 0.537 and 0.467, respectively (P < 0.05). For the intraobserver reliability, a Bland and Altman plot showed that the mean difference ± 1.96 SD were within ±0.15 mm Al eq. with the mean difference value small than 0.003 mm Al eq. For the interobserver reliability, the mean difference ±1.96 SD were within ±0.11 mm Al eq. with the mean difference of 0.008 mm Al eq.

Conclusions

A densitometric software tool has been developed, that is reliable for bone density assessment. It now requires further investigation to evaluate its accuracy and clinical applicability in large scale studies.     

基层医院腹腔镜子宫切除术两种术式的比较

目的比较腹腔镜辅助阴式子宫切除术及腹腔镜全子宫切除术的临床应用价值。方法对腹腔镜下全子宫切除术(TLH组)44例和腹腔镜下辅助阴式子宫切除术(LAVH组)24例患者的临床资料进行回顾性分析,比较两种术式、手术时间、术中出血量、术后恢复情况。结果 TLH组手术时间短,术中出血量少于LAVH组,差异有统计学意义(P0.05);术后恢复、并发症比较差异无统计学意义(P0.05)。结论基层医院应用腹腔镜行全子宫切除安全可行,对腹腔镜操作熟练者TLH更值得推广。     

Respiratory liver motion simulator for validating image-guided systems ex-vivo

Objective: A clinically realistic phantom incorporating respiratory motion was developed for validating image-guided systems for the liver. Materials and methods: The respiratory liver motion simulator consists of a physical human torso model which allows for an explanted human or porcine liver to be mounted adjacent to an artificial diaphragm. The apparatus can be connected to a lung ventilator for simulation of respiratory motion and is compatible with computed tomography (CT) and magnetic resonance imaging (MRI). To analyze the liver movement generated by the simulator, we examined three porcine livers mounted to the phantom and monitored their movement with a set of optically tracked fiducial needles. Results: Mean displacement between expiration and inspiration was 15.0 ± 4.7 mm, with craniocaudal movement making up the main part (14.2 ± 4.9 mm). In addition, the livers showed movement due to tissue deformation. Conclusion: The liver movement generated by the motion simulator is comparable to that of a human liver in vivo. The phantom thus provides a low-cost alternative to animal experiments for validating image-guided systems.     

Anthropomorphic liver phantom with flow for multimodal image-guided liver therapy research and training

Purpose

The objective of this study was to develop a multimodal, permanent liver phantom displaying functional vasculature and common pathologies, for teaching, training and equipment development in laparoscopic ultrasound and navigation.

Methods

Molten wax was injected simultaneously into the portal and hepatic veins of a human liver. Upon solidification of the wax, the surrounding liver tissue was dissolved, leaving a cast of the vessels. A connection was established between the two vascular trees by manually manipulating the wax. The cast was placed, along with different multimodal tumor models, in a liver shaped mold, which was subsequently filled with a polymer. After curing, the wax was melted and flushed out of the model, thereby establishing a system of interconnected channels, replicating the major vasculature of the original liver. Thus, a liquid can be circulated through the model in a way that closely mimics the natural blood flow.

Results

Both the tumor models, i.e., the metastatic tumors, hepatocellular carcinoma and benign cyst, and the vessels inside the liver model, were clearly visualized by all the three imaging modalities: CT, MR and ultrasound. Doppler ultrasound images of the vessels proved the blood flow functionality of the phantom.

Conclusion

By a two-step casting procedure, we produced a multimodal liver phantom, with open vascular channels, and tumor models, that is the next best thing to practicing imaging and guidance procedures in animals or humans. The technique is in principle applicable to any organ of the body.

     

An improved balloon snake for HIFU image-guided system

Target segmentation in ultrasound images is a key step in the definition of the intro-operative planning of high-intensity focused ultrasound therapy. This paper presents an improvement for the balloon snake in segmentation. A sign function, designed by the edge map and the moving snake, is added to give the direction of the balloon force on the moving snake separately. Segmentation results are demonstrated on ultrasound images and the effectiveness and convenience shown in applications.     

A three-component deformation model for image-guided surgery

In image-guided surgery it is necessary to align preoperative image data with the patient. The rigid-body approximation is usually applied, but is often not valid due to tissue deformation. Non-rigid deformation algorithms have been applied to related, but not identical problems, such as atlas matching and surgery simulation. In image-guided surgery we have the additional information that the deformation is constrained by the physical properties of the different tissues. The most important properties that must be incorporated are the rigidity of bone, the unconstrained nature of fluid regions and the relatively smooth deformation of soft tissue. Hence, we have developed a simplified model of tissue deformation based on a three-component system. Rigid regions are constrained by the rigid-body transformation and fluid regions are unconstrained. A number of energy models for deformable tissues have been compared. The model can be deformed using intraoperative data, in this case landmarks, using a technique similar to active contours. A novel strategy to avoid folding in the transformation is described. Our method was applied to MRI and CT data from a neurosurgery patient with epilepsy. Although the current implementation is only two dimensional, the initial results are promising. As the algorithm must ultimately run in or near 'real-time' an improved implementation of the energy minimization is underway. This paper presents the problem of tissue deformation, which has received little attention in the literature and outlines the framework we have developed for tackling this difficult subject.     

Radiation exposure during image-guided endoscopic procedures: The next quality indicator for endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is one of the most frequently used image-guided procedures in gastrointestinal endoscopy. Post-ERCP pancreatitis is an important concern, and prophylaxis, cannulation and other related technical procedures have been well documented by endoscopists. In addition, medical radiation exposure is of great concern in the general population because of its rapidly increasing frequency and its potential carcinogenic effects. International organizations and radiological societies have established diagnostic reference levels, which guide proper radiation use and serve as global standards for all procedures that use ionizing radiation. However, data on gastrointestinal fluoroscopic procedures are still lacking because the demand for these procedures has recently increased. In this review, we present the current status of quality indicators for ERCP and the methods for measuring radiation exposure in the clinical setting as the next quality indicator for ERCP. To reduce radiation exposure, knowledge of its adverse effects and the procedures for proper measurement and protection are essential. Additionally, further studies on the factors that affect radiation exposure, exposure management and diagnostic reference levels are necessary. Then, we can discuss how to manage medical radiation use in these complex fluoroscopic procedures. This knowledge will help us to protect not only patients but also endoscopists and medical staff in the fluoroscopy unit.     

Optimizing modality selection for image-guided procedures: an analysis of the challenges to ultrasound guidance

Introduction

Selection of the most appropriate modality for image guidance is essential for procedural success. We identified specific factors contributing to failure of ultrasound-guided procedures that were subsequently performed using CT guidance.

Materials and methods

This single-center, retrospective study included 164 patients who underwent a CT-guided biopsy, aspiration/drainage, or ablation after initially having the same procedure attempted unsuccessfully with ultrasound guidance. Review of the procedure images, reports, biopsy results, and clinical follow-up was performed and the reasons for inability to perform the procedure with ultrasound guidance were recorded. Patient cross-sectional area and depth to target were calculated. Differences in area and depth were compared using general linear modeling. Depth as a predictor of an unfavorable body habitus designation was modeled using logistic regression.

Results

US guidance was successful in the vast majority of cases (97%). Of the 164 procedures, there were 92 (56%) biopsies, 63 (38%) aspirations/drainages, and 9 (5%) ablations. The most common reason for procedure failure was poor acoustic window (83/164, 51%). Other reasons included target lesion being poorly discerned from adjacent tissue (61/164, 37%), adjacent bowel gas (34/164, 21%), body habitus (27/164, 16%), and gas-containing collection (22/164, 13%). Within the biopsy subgroup, patients for whom body habitus was a limiting factor were found to have on average a larger cross-sectional area and lesion depth relative to patients whose body habitus was not a complicating factor (p < 0.0001 and p = 0.0009).

Conclusion

Poor acoustic window was the most common reason for procedural failure with ultrasound guidance. In addition, as lesion depth increased, the odds that body habitus would limit the procedure also increased. If preliminary imaging suggests a limited sonographic window, particularly for deeper lesions, proceeding directly to CT guidance should be considered.

     

腹腔镜下不同手术方式治疗输卵管积水对卵巢储备功能的影响

目的 比较腹腔镜下双输卵管近端阻断远端造口术和双输卵管切除术对卵巢储备功能的影响.方法 选择因双侧输卵管积水行腹腔镜下双侧输卵管近端阻断远端造口术的不孕患者55例为研究组,以同期相同原因行腹腔镜下双侧输卵管切除术的不孕患者30例为对照组,比较两组患者手术前、术后第一个和第三个月经周期基础内分泌变化以及超促排卵周期中促性腺激素（Gn）用量和时间及体外受精-胚胎移植（IVF-ET）结局.结果 研究组术后第一个月经周期、第三个月经周期血促卵泡生成素（FSH）和雌二醇（E2）水平分别与术前比较,差异均无统计学意义（t分别=-1.01、-1.66、1.02、-0.28,P均＞0.05）;对照组术后第一个月经周期、第三个月经周期FSH和E2水平分别与术前比较,差异均无统计学意义（t分别=-0.09、-0.67、-0.50、0.20,P均＞0.05）.两组间术前、术后第一个、第三个月经周期FSH和E2比较,差异均无统计学意义（t分别=0.73、0.28、0.82、-0.84、-2.12、-0.72,P均＞0.05）;两组Gn用量、用药时间、获卵数比较,差异均无统计学意义（t分别=0.37、0.03、1.10、0.21,P均＞0.05）;两组间受精率、卵裂率、优质卵泡率、种植率、临床妊娠率和早期流产率比较,差异均无统计学意义（χ2分别=0.01、0.46、0.14、0.08、3.51、0.15,P均＞0.05）,两组间优质胚胎数和移植胚胎数比较,差异均无统计学意义（t分别=0.48、1.11,P均＞0.05）.结论 腹腔镜下双输卵管近端阻断远端造口术和双输卵管切除术后卵巢储备功能及IVF-ET妊娠结局无明显差异,两者均可作为输卵管积水患者行IVF-ET前手术预处理的主要选择方式.     

自制新型腹腔镜肝门阻断设备在腹腔镜肝细胞肝癌手术中的应用

目的:自制新型腹腔镜肝门阻断设备,并探讨其应用于肝细胞肝癌(hepatocellular carcinoma,HCC)手术中的有效性及安全性,为其临床应用奠定基础。方法:采用手术室常用气管导管(7.5mm)及输液用普通一次性输液器制作新型腹腔镜用肝门阻断设备。选择2015年3月至2016年11月我院收治的接受腹腔镜下肿瘤部分切除术的合并肝硬化的HCC患者(n=20)作为研究对象。按肿瘤部位、大小、切除范围进行匹配,患者被分为肝门阻断组和肝门非阻断组(n=10)。肝门阻断组在术中采用上述自制设备进行入肝血流阻断,术中采用腔镜超声评估肝门阻断后血流阻断效果;肝门非阻断组采用同样术式,术中不阻断肝门。比较两组患者手术时间、术中出血量、术中输血量、术后并发症等指标。结果:术中超声显示自制新型腹腔镜肝门阻断设备能够有效阻断入肝血流。肝门阻断组患者手术时间明显短于肝门非阻断组[(102.0±32.5)min vs(136.5±45.8)min],差异有统计学意义(P=0.005);肝门阻断组患者术中出血量明显少于肝门非阻断组[(80.0±69.4)mL vs(170.0±163.4)mL],差异有统计学意义(P=0.011)。两组患者术后均无手术相关并发症。结论:自制新型腹腔镜用肝门阻断设备制作简单方便,适用于各级医院;将其应用于腹腔镜肝肿瘤切除安全、有效,可显著减少术中出血、缩短手术时间,值得临床推广。     

Magnetic resonance image-guided stereotactic body radiation therapy for liver rhabdoid tumor in infancy: A case report

Extracranial malignant rhabdoid tumors are rare and aggressive tumors that typically occur in the pediatric age group and have a poor prognosis. Herein, we report a case of a one year and five months old male infant who was referred with the diagnosis of malignant rhabdoid tumor of the liver. Magnetic resonance guided stereotactic body radiotherapy was administered with concomitant chemotherapy. Treatment was well tolerated with no severe acute side effects. A 40.8% volumetric reduction of the tumor was observed at the last fraction of MR guided radiotherapy.     

Training system for laparoscopic fundoplication

Laparoscopic fundoplication is widely used today as a surgical standard for gastro-esophageal reflux disease (GERD). However, the procedures are complicated and require advanced laparoscopic skills. In addition, surgical complications correlate with the surgeon's technique and experience. Thus, a training course in laparoscopic fundoplication should be attended before performing surgery. This paper reports on a training course for laparoscopic Nissen fundoplication developed by our group. This course involves practice in suture knotting as part of the laparoscopic operation, practical experience in fundoplication using a porcine organ training model, and observation of a live operation in the operating room. The course improves laparoscopic skills via practical experience and contributes to the learning curve for laparoscopic fundoplication.     

腹腔镜肝叶切除术治疗肝脏肿瘤的研究

目的:探讨腹腔镜肝叶切除术治疗肝脏肿瘤的安全性及可行性.方法:回顾性分析经腹腔镜行肝叶切除术的18例患者,其中17例进行了腹腔镜肝叶切除术(12例为完全腹腔镜,5例为手助腹腔镜),1例转为开腹手术.切除术式包括左肝外叶切除(n=17)以及左肝内叶切除(n=1).结果:平均手术时间为110(55～ 210)min,平均住院时间为10.3(8～13)d.1例术后发生胆漏,3例患者术后出现肝功能异常,经相应治疗后顺利出院.结论:良性或恶性肝脏肿瘤的患者经认真评估,行腹腔镜肝叶切除术是安全可行的,随着手术经验的积累可能替代开腹切除.     

Useful maneuvers for precise laparoscopic liver resection

Laparoscopic liver resection has evolved over the past decade and nearly replaced open exploration. This procedure not only provides comparable oncological outcomes, but it also has improved recovery after surgery. Many of the challenges presented by limitations of instruments and techniques have been overcome through adaptations and new developments, and it is possible that the remaining obstacles will be overcome within a few years. Moreover, as surgeons continue to gain experience, their technical knowledge has supported further improvement in minimally invasive approaches. This review examines every important procedures in performing a precise laparoscopic liver resection.     

供肝的不同灌注方法在大鼠肝移植中的应用

目的:探讨大鼠肝移植时供肝的不同灌注方法对大鼠的影响.方法:80只大鼠随机分为供、受体两组(各40只),供体组再随机均分为经腹主动脉灌注组(A组)和经门静脉灌注组(B组)以获取供肝,应用改良二袖套法进行大鼠原位肝移植.检测两组供肝切取时间,热缺血时间,术后第1、4、7、10天的肝功能,术后一般情况及生存率等.结果:A组和B组的供肝切取时间分别为(30.0±3.0)min和(27.0±3.0)min,热缺血时间分别为(2.0±0.5)min和(1.0±0.5)min;A组术后第1天的丙氨酸氨基转移酶、天冬氨酸氨基转移酶、总胆红素等均较B组高,而术后第7天的结果却相反.结论:对于非肝动脉化的大鼠肝移植手术供肝采用经门静脉灌注的方法操作较简单,供肝切取时间较短,热缺血时间短,术后早期肝功能的损害较小,但恢复速度相对较慢.