Application of Computed Tomography Virtual Noncontrast Spectral Imaging in Evaluation of Hepatic Metastases: A Preliminary Study

Objective:

The objective was to qualitatively and quantitatively evaluate hepatic metastases using computed tomography (CT) virtual noncontrast (VNC) spectral imaging in a retrospective analysis.

Methods:

Forty hepatic metastases patients underwent CT scans including the conventional true noncontrast (TNC) and the tri-phasic contrast-enhanced dual energy spectral scans in the hepatic arterial, portal venous, and equilibrium phases. The tri-phasic spectral CT images were used to obtain three groups of VNC images including in the arterial (VNCa), venous (VNCv), and equilibrium (VNCe) phase by the material decomposition process using water and iodine as a base material pair. The image quality and the contrast-to-noise ratio (CNR) of metastasis of the four groups were compared with ANOVA analysis. The metastasis detection rates with the four nonenhanced image groups were calculated and compared using the Chi-square test.

Results:

There were no significant differences in image quality among TNC, VNCa and VNCv images (P > 0.05). The quality of VNCe images was significantly worse than that of other three groups (P < 0.05). The mean CNR of metastasis in the TNC and VNCs images was 1.86, 2.42, 1.92, and 1.94, respectively; the mean CNR of metastasis in VNCa images was significantly higher than that in other three groups (P < 0.05), while no statistically significant difference was observed among VNCv, VNCe and TNC images (P > 0.05). The metastasis detection rate of the four nonenhanced groups with no statistically significant difference (P > 0.05).

Conclusions:

The quality of VNCa and VNCv images is identical to that of TNC images, and the metastasis detection rate in VNC images is similar to that in TNC images. VNC images obtained from arterial phase show metastases more clearly. Thus, VNCa imaging may be a surrogate to TNC imaging in hepatic metastasis diagnosis.     

Virtual chromoendoscopy in small bowel capsule endoscopy: New light or a cast of shadow?

AIM: To evaluate whether virtual chromoendoscopy can improve the delineation of small bowel lesions previously detected by conventional white light small bowel capsule endoscopy(SBCE). METHODS: Retrospective single center study. One hundred lesions selected from forty-nine consecutive conventional white light SBCE(SBCE-WL) examinations were included. Lesions were reviewed at three Flexible Spectral Imaging Color Enhancement(FICE) settings and Blue Filter(BF) by two gastroenterologists with ex-perience in SBCE, blinded to each other's findings, whoranked the quality of delineation as better, equivalent or worse than conventional SBCE-WL. Inter-observer percentage of agreement was determined and analyzed with Fleiss Kappa(k) coefficient. Lesions selected for the study included angioectasias(n = 39), ulcers/ero-sions(n = 49) and villous edema/atrophy(n = 12). RESULTS: Overall, the delineation of lesions was im-proved in 77% of cases with FICE 1, 74% with FICE 2, 41% with FICE 3 and 39% with the BF, with a percent-age of agreement between investigators of 89%(k = 0.833), 85%(k = 0.764), 66%(k = 0.486) and 79%(k = 0.593), respectively. FICE 1 improved the delineation of 97.4% of angioectasias, 63.3% of ulcers/erosions and 66.7% of villous edema/atrophy with a percentage of agreement of 97.4%(k = 0.910), 81.6%(k = 0.714) and 91.7%(k = 0.815), respectively. FICE 2 improved the delineation of 97.4% of angioectasias, 57.1% of ulcers/erosions and 66.7% of villous edema/atrophy, with a percentage of agreement of 89.7%(k = 0.802), 79,6%(k = 0.703) and 91.7%(k = 0.815), respectively. FICE 3 improved the delineation of 46.2% of angioecta-sias, 24.5% of ulcers/erosions and none of the cases of villous edema/atrophy, with a percentage of agreement of 53.8% [k = not available(NA)], 75.5%(k = NA) and 66.7%(k = 0.304), respectively. The BF improved the delineation of 15.4% of angioectasias, 61.2% of ulcers/erosions and 25% of villous edema/atrophy, with a per-centage of agreement of 76.9%(k = 0.558), 81.6%(k = 0.570) and 25.0%(k = NA), respectively.CONCLUSION: Virtual chromoendoscopy can improve the delineation of angioectasias, ulcers/erosions and villous edema/atrophy detected by SBCE, with almost perfect interobserver agreement for FICE 1.     

术前虚拟设计在股前外侧皮瓣修复口腔颌面部缺损中的应用

目的:探讨术前数字化技术虚拟设计股前外侧皮瓣应用于口腔颌面部缺损修复重建中的可行性及精确性。方法:选择2019年6月至10月就诊于北京大学口腔医院口腔颌面外科的10例采用股前外侧皮瓣修复口腔颌面部缺损的患者。术前应用高频彩色多普勒超声对患者股前外侧皮瓣穿支进行定位,明确穿支位置;利用螺旋CT对患者下肢进行扫描,获取DICOM格式的CT数据,将之导入Proplan CMF 3.0软件,进行股前外侧皮瓣虚拟设计,并计算皮瓣体积;术中按照术前设计进行股前外侧皮瓣制备,并利用排水法对皮瓣实际体积进行测量,计算术前高频彩色多普勒超声定位的股前外侧皮瓣穿支位置与术中穿支实际穿出位置的符合率。应用配对样本t检验统计分析术前虚拟设计的股前外侧皮瓣体积与术中排水法所测得的皮瓣实际体积之间的差异。结果:术前利用彩色多普勒超声共发现皮瓣内穿支15支,术中实际发现穿支16支,总体符合率为87.5%。术前虚拟设计的股前外侧皮瓣体积与术中排水法所测得的皮瓣实际体积之间的差异无统计学意义(t=0.318,P=0.758)。结论:采用数字化技术对股前外侧皮瓣进行术前虚拟设计的方法具有良好的可行性和精确性,可用于指导术中制备股前外侧皮瓣。     

The evolution of craniofacial resection: A new workflow for virtual planning in complex craniofacial procedures

Complex craniofacial surgery has been later to take advantage of computerized planning than traditional maxillofacial procedures. Virtual reality, 3D model navigation, and bioengineering analyses have changed our approach to the surgical planning of craniofacial resection, increasing the benefits of surgery in terms of accuracy while decreasing complication rate.This study introduces a new workflow for 3D reconstruction, virtual model navigation, and alignment analyses, and demonstrates its successful application in a sample of four patients. A case of squamous cell carcinoma of the maxillary and ethmoid sinus in a 62-year-old patient is presented to evaluate the application of the workflow for a combined transfacial and transcranial resection. Results demonstrate that virtual surgical planning was successfully translated into navigational coordinates and reproduced in the operating room.While the literature provides a wide range of applications of virtual planning for traditional maxillofacial procedures, its introduction for complex craniofacial procedures remains difficult. The presented case shows that it is worth investigating the correlation between virtual reality planning and surgical accuracy for craniofacial resection, and related advantages in terms of surgical safety and improved prognosis.     

Applications of Technology in Neuropsychological Assessment

Most neuropsychological assessments include at least one measure that is administered, scored, or interpreted by computers or other technologies. Despite supportive findings for these technology-based assessments, there is resistance in the field of neuropsychology to adopt additional measures that incorporate technology components. This literature review addresses the research findings of technology-based neuropsychological assessments, including computer- and virtual reality-based measures of cognitive and functional abilities. We evaluate the strengths and limitations of each approach, and examine the utility of technology-based assessments to obtain supplemental cognitive and behavioral information that may be otherwise undetected by traditional paper-and-pencil measures. We argue that the potential of technology use in neuropsychological assessment has not yet been realized, and continued adoption of new technologies could result in more comprehensive assessment of cognitive dysfunction and in turn, better informed diagnosis and treatments. Recommendations for future research are also provided.     

A novel motion tracking system for evaluation of functional rehabilitation of the upper limbs

Upper limb function impairment is one of the most common sequelae of central nervous system in jury, especially in stroke patients and when spinal cord injury produces tetraplegia. Conventional assessment methods cannot provide objective evaluation of patient performance and the effec tiveness of therapies. The most common assessment tools are based on rating scales, which are inefficient when measuring small changes and can yield subjective bias. In this study, we designed an inertial sensorbased monitoring system composed of five sensors to measure and analyze the complex movements of the upper limbs, which are common in activities of daily living. We devel oped a kinematic model with nine degrees of freedom to analyze upper limb and head movements in three dimensions. This system was then validated using a commercial optoelectronic system. These findings suggest that an inertial sensorbased motion tracking system can be used in patients who have upper limb impairment through data integration with a virtual realitybased neurorehabili tation system.