Breast cancer metastasis to bone: evaluation of bioluminescent imaging and microSPECT/CT for detecting bone metastasis in immunodeficient mice

This study sought to determine if weekly X-ray exposure affected breast cancer cell metastasis to bone and to also evaluate the use of bioluminescent imaging (BLI) and microSPECT for detection of metastatic bone lesions. Five week old nude mice were randomly assigned to the CT exposed (n = 7) and no CT exposure (n = 6) treatment groups. Mice received an intracardiac injection of MDA-MB-435 human breast cancer cells transduced with luciferase, or a sham injection (saline). The CT exposed group of mice received CT irradiation once a week for 5 weeks. All mice underwent weekly BLI and select mice received Tc-99m-MDP followed by microSPECT imaging after 5 weeks. Pathological evaluation and histomorphometry were used to assess the affect of CT X-rays on bone metastasis and to evaluate BLI. BLI results found no significant difference in metastasis between animals that received CT and those that did not (P > 0.05); however, histomorphometry of the knee joints revealed a significant increase (P = 0.029) in tumor area of the leg bones in mice that received CT exposure (60% ± 7%) compared to animals that did not receive CT scans (33% ± 8%). Compared to histological analysis, BLI of the leg and spine was determined to have excellent sensitivity (100%), good specificity (80–90%) and accuracy (90–96%), a positive predictive value of 81–93% and a 100% negative predictive value. Thus, multi-modality imaging techniques can be very useful for monitoring bone metastasis, however microCT X-rays should be used judiciously in order to limit irradiation that may stimulate increased metastasis to specific regions of the skeleton. MicroSPECT imaging did not detect metastatic lesions in the legs of these young nude mice.     

Evaluation of the Image Quality of Temporal Subtraction Images Produced Automatically in a PACS Environment

The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P < 0.05), relative horizontal shift distance (P < 0.05), and standard deviation of gray levels (P < 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.     

The reduction of artifacts due to metal hip implants in CT-attenuation corrected PET images from hybrid PET/CT scanners

CT beam hardening artifacts near metal hip implants may erroneously enhance or diminish radiotracer uptake following CT attenuation correction (AC) of PET images. An artifact reduction algorithm (ARA) was developed to reduce metal artifacts in CT-based AC-PET. The algorithm employed a Bayes classifier to identify beam-hardening artifacts, followed by a partial correction of the attenuation map. ARA was implemented on phantom and patient 18F-FDG studies using a clinical PET/CT scanner. In phantom studies ARA successfully removed two artifacts of erroneously elevated uptake near a stainless steel hip prosthesis which were depicted in the standard CT-AC PET. ARA has also identified two targets absent on the scanner PET images. Target-to-background ratios were 1.5-3 times higher for ARA-PET than scanner images. In a patient study, metal artifacts were of lower intensity in ARA-PET as compared to standard images. Potentially, ARA may improve detectability of small lesions located near metal hip implants.     

Development of Digital Subtraction Angiography for Coronary Artery

The purpose of this research is to develop a new method of digital subtraction angiography (DSA) that can be applied to real time with reducing motion artifacts caused by heart movement and respiration. To create the mask image for DSA, the maximum pixel value at each pixel (which is the opposite pixel value to that of a vessel filled by contrast medium) was selected from the previous 14 image frames. The search area for the maximum pixel value was selected using the value of the standard deviation (SD) for each pixel from the previous 14 image frames. When the SD value in the 14 frames was greater than a threshold level, the search area of the maximum value became 1 pixel × 1 pixel × 14 frames; otherwise, 7 pixels × 7 pixels × 7 frames. The image quality of new DSA was evaluated on 20 coronary arteriogram images, including various degrees of occlusion or stenosis. The results indicated a considerable improvement in DSA image quality; thus, the coronary arteries, carotid artery, and vein were clearly enhanced.     

Assessment of Coronary Artery Calcium Using Dual-Energy Subtraction Digital Radiography

Cardiovascular disease is the leading cause of global mortality, yet its early detection remains a vexing problem of modern medicine. Although the computed tomography (CT) calcium score predicts cardiovascular risk, relatively high cost ($250–400) and radiation dose (1–3 mSv) limit its universal utility as a screening tool. Dual-energy digital subtraction radiography (DE; <$60, 0.07 mSv) enables detection of calcified structures with high sensitivity. In this pilot study, we examined DE radiography’s ability to quantify coronary artery calcification (CAC). We identified 25 patients who underwent non-contrast CT and DE chest imaging performed within 12 months using documented CAC as the major inclusion criteria. A DE calcium score was developed based on pixel intensity multiplied by the area of the calcified plaque. DE scores were plotted against CT scores. Subsequently, a validation cohort of 14 additional patients was independently evaluated to confirm the accuracy and precision of CAC quantification, yielding a total of 39 subjects. Among all subjects (n = 39), the DE score demonstrated a correlation coefficient of 0.87 (p < 0.0001) when compared with the CT score. For the 13 patients with CT scores of <400, the correlation coefficient was −0.26. For the 26 patients with CT scores of ≥400, the correlation coefficient yielded 0.86. This pilot study demonstrates the feasibility of DE radiography to identify patients at the highest cardiovascular risk. DE radiography’s accuracy at lower scores remains unclear. Further evaluation of DE radiography as an inexpensive and low-radiation imaging tool to diagnose cardiovascular disease appears warranted.     

先天性外中耳畸形颞骨发育程度及面神经垂直段位置变化的影像学研究

目的：应用cT影像资料研究外耳道闭锁组与狭窄组之间颞骨发育程度的差异及面神经垂直段位置的变异特征。方法：收集71例先天性外中耳畸形142侧颞骨CT影像资料。按照外耳道骨性段最宽处直径大小分为外耳道闭锁组、狭窄组和正常的对侧耳为对照组。比较3组颞骨Jahrsdoerfer（Js）评分值、面神经垂直段位置及乳突气房容积等的差异。结果：耳道闭锁组的颞骨Js评分为7．26±2．02,耳道狭窄组为8．92±1．02,耳道正常组为10±0。3组间比较差异有统计学意义（P〈0．05）。在面神经垂直段起点层面,闭锁组、狭窄组分别与正常组比较,面神经向前、向外移位明显,差异有统计学意义（P〈0．05）;在面神经垂直段终点层面,闭锁组与正常组比较,垂直段面神经向前、外移位明显,差异有统计学意义（P〈0．05）,狭窄组与对照组、闭锁组与狭窄组相比,其差异无统计学意义（P〉0．05）。3组间乳突气房容积比较,差异无统计学意义（P〉0．05）。闭锁组和狭窄组内的Js评分与乳突气房容积、乳突气房容积与面神经至棘孔和乳突距离、Js评分与面神经至棘孔距离间关系,均成正相关。结论：颞骨总体发育情况与外耳道的发育基本一致,闭锁组Js评分最低,其颞骨发育相对最差。畸形外耳道（闭锁或狭窄）相对于正常外耳道而言,面神经垂直段位置变化较大,其前移、外移程度与颞骨发育情况、乳突气化大小密切相关。     

基于物质灰度正态分布的CT断层图像匹配插值

基于医学CT断层图像中物质灰度呈正态分布的特性,提出一种新的插值算法。先分割CT断层图像,再为每个插值点搜索属于同种物质的最佳匹配点对,最后基于物质灰度呈正态分布特性获取插值权值,计算出插值点的灰度值。针对灰度值相差较大的匹配点对,传统的线性插值方法容易生成误差,新算法避免了这些插值点误差的产生。对于存在较多灰度值差异大的匹配点对的4组测试切片,测试结果表明,与匹配点对间传统的线性插值方法相比较,新算法的标记点均偏差平均降低29.55%,说明新算法具有良好的插值效果。     

高分辨率CT在颞骨骨折及其并发症诊治中的临床价值

目的：探讨高分辨率CT（HRCT）在颞骨骨折及其并发症的诊断和治疗中的临床价值。方法：对颞骨骨折患者58例（59耳）采用HRCT横断位及冠状位扫描，并与已手术探查的26例病例作对照性比较。结果：术前HRCT示面神经管损伤32例，听骨链损伤16例，内耳迷路损伤7例，脑脊液漏3例；26例手术病例的术中诊断与HRCT诊断一致，且26例手术疗效均满意。结论：HRCT对确诊颞骨骨折及其并发症，帮助术者制定手术方案，提高手术成功率有较高的临床价值：     

18F-FDG PET/CT与CT诊断胃癌淋巴结转移直接比较的系统评价

目的 采用Meta分析和直接比较方法系统评价18F-FDG PET/CT与CT对胃癌淋巴结转移的诊断价值.方法 使用计算机系统检索中国期刊全文数据库、中文科技期刊数据库、万方数据库、PubMed、Embase、The Cochrane Library,从建库至2016年11月,搜索直接比较18F-FDG PET/CT与CT诊断胃癌淋巴结转移的诊断性比较试验.用Meta-Disc1.4软件进行分析,计算两种影像学诊断方法的合并灵敏度(sensitivity,SEN)、合并特异性(specificity,SPE)、合并阳性似然比(positive likelihood ratio,+LR)、合并阴性似然比(negative likelihood ratio,-LR),诊断优势比(diagnostic OR,DOR),并绘制SROC (summary receiver operating characteristic)曲线,计算曲线下面积(area under curve,AUG).结果 最终共纳入9篇文章,Meta分析结果显示,18F-FDG PET/CT对胃癌淋巴结转移诊断的合并SEN为0.51(95％ CI =0.47～0.55),合并SPE为0.92(95％ CI =0.89 ～0.94),合并+LR为5.77(95％ CI =4.38 ～7.59),合并-LR为0.54(95％ CI =0.45 ～0.64),DOR为12.71(95％ CI =8.97～ 18.01),AUC为0.8101.CT诊断的合并SEN为0.71(95％ CI=0.67～ 0.74),合并SPE为0.82(95％ CI =0.78 ～0.84),合并+LR为3.52(95％ CI=2.52 ～4.93),合并-LR为0.37(95％CI=0.32～0.44),DOR为10.73(95％ CI =7.35 ～ 15.66),AUC为0.8176.结论 18F-FDG PET/CT显像诊断胃癌淋巴结转移的灵敏度比CT低,但其特异性较好,有更高的诊断价值,可作为胃癌淋巴结转移的临床诊断方法之一.     

定量CT测定骨矿物含量的双能量方法

骨质疏松症最早显示在椎骨小梁骨的变化上。用定量ＣＴ测量椎骨小梁骨矿物质含量，可对该病进行早期诊断。双能量方法可分离出脂肪影响。提高测试精度。对两种双能量方法定量地分析了它们的系统误差和随机误差，并与单能量方法的误差对照。完成了２０个临床病例的试验。单能量ＣＴ系统误差较大，双能量ＣＴ随机误差较大，但若ＣＴ机的测试误差控制在正常范围内，则双能量ＣＴ的总误差明显地小于单能量ＣＴ的总误差。故认为双能量方法     

影响颅内支架CT血管成像的相关因素分析

目的:探讨影响颅内支架CT血管造影(CTA)成像质量的相关因素。方法:回顾性研究。纳入首都医科大学附属北京朝阳医院2016年7月—2019年10月颅内动脉置入支架、均行CTA及数字减影血管造影(DSA)检查的35例患者的临床资料,其中男28例、女7例,年龄37～83(60.6±7.9)岁,共留置支架35枚。以DSA为金...     

Integration of Temporal Subtraction and Nodule Detection System for Digital Chest Radiographs into Picture Archiving and Communication System (PACS): Four-year Experience

Since May 2002, temporal subtraction and nodule detection systems for digital chest radiographs have been integrated into our hospital’s picture archiving and communication systems (PACS). Image data of digital chest radiographs were stored in PACS with the digital image and communication in medicine (DICOM) protocol. Temporal subtraction and nodule detection images were produced automatically in an exclusive server and delivered with current and previous images to the work stations. The problems that we faced and the solutions that we arrived at were analyzed. We encountered four major problems. The first problem, as a result of the storage of the original images’ data with the upside-down, reverse, or lying-down positioning on portable chest radiographs, was solved by postponing the original data storage for 30 min. The second problem, the variable matrix sizes of chest radiographs obtained with flat-panel detectors (FPDs), was solved by improving the computer algorithm to produce consistent temporal subtraction images. The third problem, the production of temporal subtraction images of low quality, could not be solved fundamentally when the original images were obtained with different modalities. The fourth problem, an excessive false-positive rate on the nodule detection system, was solved by adjusting this system to chest radiographs obtained in our hospital. Integration of the temporal subtraction and nodule detection system into our hospital’s PACS was customized successfully; this experience may be helpful to other hospitals.     

The thin sectional anatomy of the temporal bone correlated with multislice spiral CT

The aim of this study was to explore the method for obtaining the thin sectional anatomy data of the adult temporal bone and study the fine structures using this method. Three fresh adult cadaveric heads were scanned with multi-slice computer tomography (MSCT) centered on petrous bones. The CT images of 0.6 mm were obtained by multi-planar reformation (MPR). The slices of 0.1 mm were shaved off the specimen in the axial direction with the numerical control milling machine after being embedded and frozen, pictures of which were taken by the digital camera and saved in the computer. The thin axial sectional anatomic structures of the intra-temporal were investigated and correlated with MPR images. Via the comparison, fifty micro-anatomic structures of the temporal bone that can’t be delineated clearly or missed in the thick sections were evaluated. The anatomical details of the temporal bone can be clearly delineated in MSCT in sub-millimeter and were identical to those in sectional anatomy images. This method can supply anatomical details that had been missed or overlooked for imaging diagnosis and surgical anatomy.     

Accurate Matching of electromagnetic dipole data with CT and MR images

Interpretation of EEG (electroencephalography) or MEG (magnetoencephalography) derived three-dimensional dipole localizations is hampered by poor visualization. This paper describes a method for combining dipole data with structural image data of the same patient. To ensure high precision this method utilizes external markers that are easy to apply. These markers can achieve subslice accuracy and can even be used to pinpoint reference points outside the scanned volume. Accurate matching is thus provided even in standard imaging protocols employing thick slices and/or large interslice gaps. The results of the matching method are presented in 2D and 3D visualizations. The hybrid images facilitate the interpretation of dipole localizations with respect to the patient's anatomy.     

能谱CT成像与颈部血管超声评价颈动脉狭窄的对比研究

目的 探讨能谱CT成像与颈部血管超声在颈动脉狭窄评价中的应用价值。方法 纳入2016年6月—2021年6月河南省驻马店市中心医院数字减影血管造影（DSA）确诊为颈动脉狭窄的缺血性脑卒中（IS）患者289例,其中男159例、女130例,年龄43~82（61.7±8.0）岁。患者均行能谱CT和颈部血管超声检查,以DSA诊断结果为金标准,比较能谱CT及颈部血管超声诊断颈动脉狭窄程度的一致性;比较2种检查方法对不同程度颈动脉狭窄的诊断效能;比较2种检查方法对颈总动脉易损斑块的检出率。结果 以DSA诊断结果为金标准,能谱CT及超声检测颈动脉狭窄程度Kappa值分别为0.844、0.882,均具有较好的一致性;除了颈部血管超声诊断颈动脉轻度狭窄的灵敏度较低、能谱CT诊断颈动脉轻度狭窄的阳性预测值较低外,能谱CT及颈部血管超声对不同程度颈动脉狭窄的诊断均具有较高的准确率、灵敏度、特异度、阳性预测值及阴性预测值。在颈总动脉上,DSA共检出易损斑块1 672个;颈部血管超声检出876个,其中软斑块384个、表面不规则斑块80个、溃疡斑412个,易损斑块检出率为52.39%（876/1 672）;能谱CT检出367个,均为软斑块,易损斑块检出率为21.95%（367/1 672）。血管超声易损斑块检出率高于能谱CT,差异有统计学意义（χ²=509.00,P<0.001）。结论 能谱CT成像与颈部血管超声均能准确判断颈动脉狭窄程度,超声可能在颈总动脉易损斑块评估中更具价值,临床应用时可将两种方式联合使用。     

3D打印PEEK材料假体置入CT表现：骨肿瘤患者10例

目的 阐述3D打印PEEK材料置入后随访的CT特征及改变。方法 回顾性分析2020年2月至2021年6月间骨肿瘤患者行瘤段切除3D打印PEEK材料假体置入后的CT图像10例,通过多平面重组观察、测量CT值等方法分析假体形态、密度改变及假体－骨界面的情况。结果 10例假体均未发生变形及折断,各个假体与骨接触面密度均无较大改变,残留骨与假体接触面发生不同程度骨质吸收。10例中有5例残留骨表面出现骨膜新生骨,2例出现感染,1例出现脱位表现。均未见肿瘤复发征象。结论 CT可以评估假体的位置、形态、密度改变及与自体骨间关系,可以发现相应的并发症,是这类手术患者术后首选的随访方法。     

Fast segmentation of bone in CT images using 3D adaptive thresholding

Fast bone segmentation is often important in computer-aided medical systems. Thresholding-based techniques have been widely used to identify the object of interest (bone) against dark backgrounds. However, the darker areas that are often present in bone tissue may adversely affect the results obtained using existing thresholding-based segmentation methods. We propose an automatic, fast, robust and accurate method for the segmentation of bone using 3D adaptive thresholding. An initial segmentation is first performed to partition the image into bone and non-bone classes, followed by an iterative process of 3D correlation to update voxel classification. This iterative process significantly improves the thresholding performance. A post-processing step of 3D region growing is used to extract the required bone region. The proposed algorithm can achieve sub-voxel accuracy very rapidly. In our experiments, the segmentation of a CT image set required on average less than 10 s per slice. This execution time can be further reduced by optimizing the iterative convergence process.     

DeskCAT互动CT教学实验系统剖析——兼谈CT的实验教学

该文作者根据多年来对医学成像课程的教学实践与体会,结合医院、医学院校与高校有关专业的教学实验需求,总结了国际上CT实验教学的四种模式:自编程模式、MATLAB模式、DR+转台模式以及台式CT教学实验模式。着重介绍了加拿大MODUS公司设计的基于光学射线源的台式CT教学实验系统:Desk CAT。剖析了其结构特点和优点,介绍了该系统的许多重要功能例如能仿真SPECT与双能CT等。     

Na18F PET/CT用于恶性肿瘤骨转移诊断的Meta分析

目的Na^18F是一种主要用于诊断成骨反应活性程度增加的骨疾病的正电子计算机断层显像药物,肿瘤骨转移的诊断是其重要的适应症之一。本研究旨在对Na18FPET/CT用于肿瘤骨转移诊断的诊断效果进行系统评价。方法对2000年1月1日至2018年12月31日公开发表的Na^18F PET/CT诊断骨转移的文献用计算机检索中英文数据库,根据纳入与排除标准筛选出符合要求的文献,进行数据提取和质量评价,采用Stata 12.00软件进行Meta分析。结果共35篇文献纳入本研究,中文文献9篇,英文文献26篇。Meta分析结果显示:①Na^18F PET/CT诊断骨转移的灵敏度、特异性、阳性似然比、阴性似然比、曲线下面积,以患者为计算基础时分别为0.97、0.93、14.5、0.03和0.99;以病灶为计算基础时分别为0.96、0.88、8.3、0.05和0.98;②对不同原发灶(肺癌、乳腺癌及前列腺癌)的ROC曲线比较可知:三种不同的原发灶之间均无显著性差异;③所有纳入本研究的文献未见有使用Na18F后出现不良反应的报道。结论无论以患者还是以病灶为基础,Na^18F PET/CT诊断骨转移的效能均很好,Na^18F PET/CT对肺癌、乳腺癌和前列腺癌骨转移的诊断效能无明显差异,未见使用Na18F后出现不良反应的报道。     

带有预处理的计划CT和在线CT的形变配准方法

CT扫描中,水溶性碘造影的存在使得计划CT和在线CT图像中血管内的HU值出现非常大的偏差,从而导致计划CT和在线CT图像错配。针对该问题,本研究提出了一种基于预处理的计划CT和在线CT形变配准方法。首先,根据CT图像组织和结构的信息,利用阈值分割方法分割出血管,并将所有分割中最大的联通区域作为初始分割的强化血管;其次,利用分割得到的强化血管区域外扩5 mm,作为外扩的强化血管,并将血管用固定的HU值进行填充;最后,对完成填充后的图像利用Demons算法进行形变配准。实验结果显示本文提出的带有预处理的形变配准方法,可以较好地解决水溶性碘造影剂引起的CT错配问题。