计算机辅助虚拟手术设计结合3D打印技术在颌骨重建的应用研究

目的明确计算机辅助虚拟手术设计结合3D打印技术在颌面部骨缺损重建的应用模式及操作规范。方法选取2014—2016年眉山市中医院收治的14例颌骨创伤及肿瘤患者,其中男性9例,女性5例;平均年龄41.5岁。经医患沟通后患者同意采用虚拟手术方式进行术前设计,通过图像数据实现患者颌骨三维重建,利用计算机虚拟手术操作,确定最佳预期设计方案;根据计算机数据通过3D打印技术实现术前、术后模型重建,通过手术比较明确临床应用价值及操作规范。结果通过对14例患者实施术前设计及模型外科,创伤患者手术时间为2~6.5h,肿瘤患者手术时间为3~4.5h。14例患者术前利用3D打印模型制定手术方案,模拟手术步骤,其中13例手术入路及手术导板放置及螺钉植入均与术前方案一致;患者的手术时间较常规手术时间平均缩短近1h。术后随访3~6个月,患者对面部轮廓及咬合关系恢复情况,其中满意9例,较满意4例,不满意1例。结论计算机辅助虚拟手术设计为颌骨修复重建手术提供了重要的手术依据和临床数据;通过3D打印技术可提高手术质量,有效缩短手术时间,减少术中和术后并发症发生率。     

A survey of case studies on the use of forensic three-dimensional printing in England and Wales

3D printing has rapidly developed and been applied in forensic science due to its use in creating demonstrations for courts of law. Much of the literature on this specific topic has focused on the use of 3D printed models in academia, the potential influence on a jury, and its use as a long-term documentation process, but with few actual forensic case examples. This paper offers an insight into the development of 3D printing in forensic practice and how 3D printing is currently being used in the criminal justice system in England and Wales.

A series of case reports were gathered from multiple police forces and forensic practitioners in the UK to identify how 3D printing was being used. These discussions established who was requesting 3D printed exhibits, what type of technologies were being utilised, what type of exhibits were being printed, and resulting feedback for the use of 3D printed material within a criminal case. As a result, this research demonstrates the current use of 3D printing in England and Wales, discussing the associated cases that have been known to incorporate 3D prints. Likewise, this work explores the limitations that have been encountered by forensic practitioners and identifies a series of research questions that should be considered in future investigations.

     

Evaluation of referenceless thermometry in MRI-guided focused ultrasound surgery of uterine fibroids

Purpose

To clinically assess a previously described method (Rieke et.al., Magn Reson Med 2004) to produce more motion‐robust MRI‐based temperature images using data acquired during MRI‐guided focused ultrasound surgery (MRgFUS) of uterine fibroids.

Materials and Methods

The method (“referenceless thermometry”) uses surface fitting in nonheated regions of individual phase images to extrapolate and then remove background phase variations that are unrelated to temperature changes. We tested this method using images from 100 sonications selected from 33 patient MRgFUS treatments. Temperature measurements and thermal dose contours estimated with the referenceless method were compared with those produced with the standard phase‐difference technique. Fitting accuracy and noise level were also measured.

Results

In 92/100 sonications, the difference between the two measurements was less than 3°C. The average difference in the measurements was 1.5 ± 1.4°C. Small motion artifacts were observed in the phase‐difference imaging when the difference was greater than 3°C. The method failed in two cases. The mean absolute error in the surface fit in baseline images corresponded to a temperature error of 0.8 ± 1.4°C. The noise level was approximately 40% lower than the phase‐difference method. Thermal dose contours calculated from the two methods agreed well on average.

Conclusion

Based on the small error when compared with the standard technique, this method appears to be adequate for temperature monitoring of MRgFUS in uterine fibroids and may prove useful for monitoring temperature changes in moving organs. J. Magn. Reson. Imaging 2008;28:1026–1032. © 2008 Wiley‐Liss, Inc.     

Evaluation of styloid process by three-dimensional computed tomography

The pupose of this paper was to investigate the length, medial angulations and other structural variants of the styloid process (SP) by three-dimensional computed tomography (3D CT) in patients without any complaints related to elongated SP. We performed temporal computed tomography (CT) scans in 138 cases (87 males, 51 females) with a mean age of 34.5 (17–86). The structure, length and medial angulation of SPs were evaluated on 3D reconstructed images. SP lengths varied between 1.58 and 5.48 cm (average length 2.83 cm), and the angles varied between 60.6 and 84.1° (average angle 69.4°). Other morphological findings were absence of SP (3 unilateral and 1 bilateral), ossification of stylohyoid ligament (9 unilateral and 27 bilateral), irregular SP (5 unilateral and 5 bilateral), fragmentation of SP (12 unilateral and 9 bilateral), absence of the proximal part (5 unilateral and 9 bilateral) and double proximal part (1 unilateral). According to our results, we propose a new classification. Absence of SP, absence of the proximal part of SP, duplication of the proximal part of SP and angle values of SP have never been reported before according to the available medical literature. 3D CT is an effective method in the evaluation of the SP length, angulations and other morphological characteristics.     

Comparison of inverse dynamics calculated by two- and three-dimensional models during walking

The purpose of the study was to compare joint moments calculated by a two- (2D) and a three-dimensional (3D) inverse dynamics model to examine how the different approaches influenced the joint moment profiles. Fifteen healthy male subjects participated in the study. A five-camera video system recorded the subjects as they walked across two force plates. The subjects were invited to approach a walking speed of 4.5 km/h. The ankle, knee and hip joint moments in the sagittal plane were calculated by 2D and 3D inverse dynamics analysis and compared. Despite the uniform walking speed (4.53 km/h) and similar footwear, relatively large inter-individual variations were found in the joint moment patterns during the stance phase. The differences between individuals were present in both the 2D and 3D analysis. For the entire sample of subjects the overall time course pattern of the ankle, knee and hip joint moments was almost identical in 2D and 3D. However, statistically significant differences were observed in the magnitude of the moments, which could be explained by differences in the joint centre location and joint axes used in the two approaches. In conclusion, there were differences between the magnitude of the joint moments calculated by 2D and 3D inverse dynamics but the inter-individual variation was not affected by the different models. The simpler 2D model seems therefore appropriate for human gait analysis. However, comparisons of gait data from different studies are problematic if the calculations are based on different approaches. A future perspective for solving this problem could be to introduce a standard proposal for human gait analysis.     

Multimaterial three-dimensional printing in brachytherapy: Prototyping teaching tools for interstitial and intracavitary procedures in cervical cancers

PurposeAs the utilization of brachytherapy procedures continues to decline in clinics, a need for accessible training tools is required to help bridge the gap between resident comfort in brachytherapy training and clinical practice. To improve the quality of intracavitary and interstitial high-dose-rate brachytherapy education, a multimaterial, modular, three-dimensionally printed pelvic phantom prototype simulating normal and cervical pathological conditions has been developed.Methods and MaterialsPatient anatomy was derived from pelvic CT and MRI scans from 50 representative patients diagnosed with localized cervical cancer. Dimensions measured from patients’ uterine body and uterine canal sizes were used to construct a variety of uteri based off of the averages and standard deviations of the subjects in our study. Soft-tissue anatomy was three-dimensionally printed using Agilus blends (shore 30 and 70) and modular components using Vero (shore 85).ResultsThe kit consists of four uteri, a standard bladder, a standard rectum, two embedded gross tumor volumes, and four clip-on gross tumor volume attachments. The three anteverted uteri in the kit are based on the smallest, the average, and the largest dimensions from our patient set, whereas the retroverted uterus assumes average dimensions.ConclusionsThis educational high-dose-rate gynecological pelvic phantom is an accessible and cost-effective way to improve radiation oncology resident training in intracavitary/interstitial brachytherapy cases. Implementation of this phantom in resident education will allow for more thorough and comprehensive physician training through its ability to transform the patient scenario. It is expected that this tool will help improve confidence and efficiency when performing brachytherapy procedures in patients.     

Evaluation of muscle layer of the uterine body by dynamic MRI

Gd-DTPA enhanced dynamic MR imaging was performed in 11 normal uteri using a 1.5-T MR unit in order to analyze normal dynamic patterns. After intravenous bolus administration of Gd-DTPA, dynamic study was performed with serial imaging-gradient echo (FLASH). In most cases of normal uteri, early enhancement was shown in peripheral zone that was similar to be junctional zone, forming inner region of muscle layer.     

子宫肌瘤栓塞术后产生疼痛的临床防治

目的 探讨子宫肌瘤栓塞术后产生疼痛的防治措施。方法 56例子宫肌瘤患者栓塞术后均出现疼痛，按对栓塞术后产生疼痛的处理方法不同分为对症组与预防组，分别为3l例和25例。通过观察2组患者术后疼痛的程度和持续时间，评价2种处理方法有无差异。结果 2组患者发生不同程度疼痛的比例无明显差异，但疼痛持续时间预防组显著较短。结论 积极地做好预防处理能有效地减轻子宫肌瘤栓塞术后产生疼痛的程度和持续时间，提高介入治疗的综合效果。     

子宫动脉栓塞治疗子宫肌瘤的生命质量观察

目的 探讨子宫动脉栓塞前后子宫肌瘤患者的生命质量变化.方法 对2003年1月-2005年3月我院收治118例行子宫动脉栓塞术患者,应用子宫肌瘤症状和生命质量(UFS-QOL)调查表评价其术前及术后生命质量的变化,并对患者进行满意度调查.同时观察子宫及肌瘤大小变化.结果 术后6个月肌瘤及子宫体积平均分别缩小49.6%和45.2%.栓塞术后患者临床症状明显好转,生命质量各因子评分均较术前明显提高,差异均有统计学意义(P＜0.001),65%患者临床症状明显改善,接近80%患者肯定或很可能再次选择UAE治疗子宫肌瘤.结论 行UAE治疗子宫肌瘤,可明显提高患者的生命质量,有较高的满意度.     

Predictability of a three-dimensional planning system for oral implant surgery.

OBJECTIVES: To compare 2D CT alone with 2D + 3D reconstruction for pre-operative planning of implant placement. METHODS: Spiral CT scans of 33 consecutive patients were used for both reformatted 2D and 3D computer-assisted planning. The number, site and size of implants and the occurrence of anatomical complications during planning and implant placement were statistically compared using the percentage agreement and the Kendall's correlation coefficients (tau). Although planning was performed in 33 patients, implants were only placed in 21 patients. In 11 patients surgery was based on 2D + 3D imaging and in ten patients on 2D planning. RESULTS: Agreement between planning and placement of implants was highly significant for the implant sites selected. For 2D based planning and placement, agreement reached 68% (tau = 0.94). For 2D + 3D based planning and placement, agreement attained 73% (tau = 0.89). For planning and placement of implant size based on 2D images, agreement was 31% and not significant (tau = 0.23). When based on 2D + 3D images, agreement for implant size was 44% (tau = 0.5). Agreement was not significant for anatomical complications: 69% for 2D planning and 71% for 2D + 3D planning (tau = 0.24 for 2D and tau = 0.21 for 2D + 3D). CONCLUSIONS: The 3D planning system is a reliable tool for pre-operative assessment of implant placement. Both 2D and 2D + 3D planning have a good predictability for the number and site of the implants but less so for anatomical complications. However, the 2D + 3D planning provides a better pre-operative assessment of implant size.     

A new landmark for measuring the Ischium-Pubis index for sex determination by using three-dimensional models of South Korean population

The Ischium-pubis index (IPI) is one of the parameters of sex determination using the hip bone. IPI is defined as the percentage of the pubis length to the ischium length. On dry bones, the combined starting point of the lengths of the pubis and ischium is in the acetabulum. In this study, we evaluated the accuracy of IPI determination by using three-dimensional computational models. We compared the accuracy of three acetabular landmarks: the traditional acetabulum notch, the deepest point of the acetabulum and the point on the superior acetabulum border. The deepest point of the acetabulum was newly defined to facilitate the computational measurement. One-hundred models reconstructed from computed tomography scans of Korean adult cadavers were measured for the pubic and ischium length. After computer-assisted landmark indication procedure on software that enables three-dimensional model handling, measurements were automatically calculated. In the Korean adult population, measurements involving the deepest point of the acetabulum have shown the highest accuracy, 91%. We compared our results with those of the former reports on pubis length, ischium length, and IPI.     

First clinical use of a standardized three-dimensional ultrasound for breast imaging

Objectives

The feasibility, image quality, and diagnostic potential of the prototype of an automated ultrasound (US) breast scanner were examined.

Methods

Ninety-seven patients with suspicious breast lesions had mammograms, manual US, and an automated breast US. The data were evaluated according to the breast imaging reporting and data system (BIRADS) classification, image quality, and amount to diagnostic information. All lesions were confirmed histological.

Results

The image quality of the three-dimensional (3D) data sets was equal to or satisfactory compared with cross-sectional images from manual US in at least 72% of cases (p < 0.05). The diagnostic information was equal or superior in at least 63% of cases (p < 0.05).

Conclusions

Standardized 3D US scanning is a promising diagnostic adjunct to mammography, but is no substitute for manual US at the current stage of development.     

Evaluation of a collapsed-cone convolution algorithm for esophagus and surface mold 192Ir brachytherapy treatment planning

PurposeTG43 does not account for a lack of scatter and tissue and applicator heterogeneities. The advanced collapsed-cone engine (ACE) algorithm available for use in the Oncentra Brachy treatment planning system (Elekta AB, Stockholm, Sweden) can model these conditions more accurately and is evaluated for esophageal and surface mold brachytherapy treatments.Methods and MaterialsACE was commissioned for use then compared against TG43 for five esophageal and five surface mold treatment plans. Dosimetric differences between each algorithm were assessed using superimposed comparisons and dose-volume histogram statistics.ResultsEsophagus (6 Gy per fraction): Compared with TG43, ACE demonstrated up to a 0.63% and 0.05 Gy reduction in planning target volume (PTV) V100% and PTV D98, respectively. Lung D2cc and bone D2cc deviated by up to 0.09 Gy and 0.03 Gy, respectively. Lung D0.1 cc and bone D0.1 cc both deviated by up to 0.12 Gy.Surface mold (4.5 Gy per fraction): Compared with TG43, ACE demonstrated up to a 12.5% and 0.18 Gy reduction in PTV V80% and PTV D98, respectively. Bone D2cc and D0.1 cc both reduced by up to 0.2 Gy when modeled with ACE. Increasing mold size laterally increased the dosimetric differences between TG43 and ACE.ConclusionsTG43 generally overestimated dose delivered to the target volume and organs at risk for the sites investigated. Dosimetric differences observed for esophageal treatments were minimal; however, surface mold treatments would benefit from the increased dosimetric accuracy offered by ACE.Implementation should be considered for surface mold ¹⁹²Ir treatment planning, but increased calculation time, additional contouring, and mass density assignment requirements should be scrutinized with regard to their potentially negative impact on current clinical practice.     

Average soft-tissue and bone models for use in radiation dosimetry

Average tissue compositions have been derived for seven groups of soft tissues found in "Reference Man". The analyses took into account some 40 soft tissues comprising the adult human. Different groups of soft tissues were selected to provide average tissue compositions of practical value in radiation dosimetry. In addition, as more reliable skeletal tissue data are now available, an updated tabulation is given of average bone formulations. Elemental compositions and mass and electron densities are tabulated for all of the derived systems.     

Evaluation of gastric cancer by high-resolution three-dimensional CISS MR imaging in vitro

ObjectiveThe objective of this study was to demonstrate the usefulness of high-resolution three-dimensional (3D) constructive interference in steady-state (CISS) MR imaging for evaluating mural invasion and the morphologic features of gastric cancers in vitro.Materials and methodsHigh-resolution 3D-CISS MR images were obtained in three surgical specimens containing three different gastric cancers.ResultsIn early carcinoma, advanced carcinoma, and leiomyosarcoma, the depth of mural invasion at 3D-CISS MR imaging correlated well with the histopathologic stage.ConclusionHigh-resolution 3D-CISS MR imaging is a useful method for evaluating mural invasion and the macroscopic features of gastric cancers in vitro.     

基于CT薄层扫描数据的3D打印技术在跟骨关节内骨折手术治疗中的应用

目的探讨基于CT薄层扫描数据的数字化设计和3D打印技术在跟骨关节内骨折手术治疗中的诊疗价值。方法选择2015年1月~2016年3月解放军306医院骨科收治的跟骨关节内骨折患者19例,高处坠落伤15例,摔伤3例,道路交通伤1例,均为新鲜单侧闭合性骨折。男性17例,女性2例;年龄21~56岁,平均38.8岁。Sander's分型:Ⅱ型9例,Ⅲ型10例。采用64排螺旋CT行薄层扫描,Mimics软件处理数据,通过阈值分割、区域增长以及蒙板编辑等完成骨折模型的三维重建,利用3D打印技术制作骨折等比例实体模型;在3D打印实体模型基础上制定手术方案,模拟内固定植入手术,最终将模拟钢板位置、钢板预弯、螺钉方向和长度等参数应用于实际手术。结果基于CT薄层扫描数据制作的3D打印实体模型可直观地真实展示跟骨关节内骨折的形态特点,8例患者均在术前模拟操作中明确钢板植入位置、螺钉方向、螺钉长度并完成钢板预塑形,手术过程顺利,术中采用的固定钢板位置、螺钉数量与螺钉长度均与术前计划一致,术后复查X线片显示跟骨关节内骨折复位固定满意,钢板及螺钉在位良好。结论基于CT薄层扫描数据的3D打印技术可快速制作跟骨关节内骨折实体模型,在此基础上完成手术模拟及手术方案设计,其应用于跟骨关节内骨折手术治疗的临床可行性良好。     

Initial experience with use of tris-acryl gelatin microspheres for uterine artery embolization for leiomyomata

PURPOSE: To assess the safety and effectiveness of tris-acryl gelatin microspheres (Embospheres) in the treatment of leiomyomata by uterine artery embolization. MATERIALS AND METHODS: This was a Phase I study of 30 patients with symptomatic leiomyomata. Each patient underwent ultrasound imaging and completed questionnaires regarding symptoms and health status at baseline and 3 and 6 months after treatment. Bilateral embolization was performed with use of tris-acryl gelatin microspheres. Summary statistics were used to characterize the demographic and procedure data. Paired t-tests were used to assess change in the severity of menstrual bleeding and health-related quality of life. RESULTS: Bilateral embolization was technically successful in all patients. Three months after treatment, menstrual bleeding was markedly improved as assessed by menorrhagia questionnaire (P <.0001) and menstrual calendar (P <.0001). Pelvic pain and discomfort was improved in 92% of cases. Physical component summary scores of the SF-12 also increased from baseline at 3 months (P =.02) and at 6 months (P =.01). Minor complications occurred in nine patients; there were no major complications. CONCLUSION: Although limited, this initial experience suggests that tris-acryl gelatin microspheres are an effective and safe embolic agent for the treatment of uterine leiomyomata.