A machine learning-based strategy for predicting the mechanical strength of coral reef limestone using X-ray computed tomography

Different sedimentary zones in coral reefs lead to significant anisotropy in the pore structure of coral reef limestone(CRL),making it difficult to study mechanical behaviors.With X-ray computed tomography(CT),112 CRL samples were utilized for training the support vector machine(SVM)-,random forest(RF)-,and back propagation neural network(BPNN)-based models,respectively.Simultaneously,the machine learning model was embedded into genetic algorithm(GA)for parameter optimization to effectively predict uniaxial compressive strength(UCS)of CRL.Results indicate that the BPNN model with five hidden layers presents the best training effect in the data set of CRL.The SVM-based model shows a tendency to overfitting in the training set and poor generalization ability in the testing set.The RF-based model is suitable for training CRL samples with large data.Analysis of Pearson correlation coefficient matrix and the percentage increment method of performance metrics shows that the dry density,pore structure,and porosity of CRL are strongly correlated to UCS.However,the P-wave velocity is almost uncorrelated to the UCS,which is significantly distinct from the law for homogenous geomaterials.In addition,the pore tensor proposed in this paper can effectively reflect the pore structure of coral framework limestone(CFL)and coral boulder limestone(CBL),realizing the quantitative characterization of the heterogeneity and anisotropy of pore.The pore tensor provides a feasible idea to establish the relationship between pore structure and mechanical behavior of CRL.

Hybrid reconstruction algorithm for computed tomography based on diagonal total variation

Inspired by total variation(TV), this paper represents a new iterative algorithm based on diagonal total variation(DTV) to address the computed tomography image reconstruction problem. To improve the quality of a reconstructed image, we used DTV to sparsely represent images when iterative convergence of the reconstructed algorithm with TV-constraint had no effect during the reconstruction process. To investigate our proposed algorithm, the numerical and experimental studies were performed, and rootmean-square error(RMSE) and structure similarity(SSIM)were used to evaluate the reconstructed image quality. The results demonstrated that the proposed method could effectively reduce noise, suppress artifacts, and reconstruct highquality image from incomplete projection data.

Relation between Epicardial Adipose Tissue Thickness Assessed by Multidetector Computed Tomography and Significance of Coronary Artery Disease

Objective: To evaluate the relation between epicardial adipose tissue (EAT) thickness and also pericoronary fat assessed by Multidetector Computed Tomography (MDCT) with both calcium score and significance of coronary artery disease. Background: Epicardial adipose tissue (the visceral fat of the heart present under the visceral layer of the pericardium) has the same origin of abdominal visceral fat, which is known to be strongly related to the development of coronary artery atherosclerosis. Multidetector CT (MDCT) provides an accurate and reproducible quantification of EAT due to its high spatial and temporal resolution. Patients and Methods: The current study included 70 patients with low-intermediate probability of coronary artery disease. All patients were subjected to 256 Multidetectors CT to assess EAT thickness, the mean thickness of the pericoronary fat surrounding the three coronary arteries and coronary calcium score. Also coronary CT angiography was done and patients were then divided into 3 groups according to significance of coronary atherosclerosis: Group 1: No atherosclerosis (20 patients), Group 2: Non obstructive atherosclerosis (luminal narrowing less than 50% in diameter) (25 patients), Group3: Obstructive atherosclerosis (luminal narrowing ≥ 50%) (25 patients). Results: The mean EAT thickness and the mean pericoronary fat thickness were significantly higher in patients with obstructive coronary artery disease (CAD) with stenosis > 50% (group 3) compared to other groups with normal coronaries or non obstructive (CAD). ROC curve was used to define the best cut off value of the thickness of both EAT and pericoronary fat in predicting the obstructive CAD group which was ≥7.2 and 12.6 mm for epicardial and pericoronary fat respectively. Also there is a positive correlation between both epicardial adipose tissue and pericoronary fat thickness and the coronary calcium score. Conclusion: EAT thickness and pericoronary fat thickness can be used in predicting the significance of coronary artery disease.

Acute coronary syndrome on non-electrocardiogram-gated contrastenhanced computed tomography

It is not rare for acute coronary syndrome(ACS)patients to present with symptoms that are atypical,rather than chest pain.It is sometimes difficult to achieve a definitive diagnosis of ACS for such patients who present with atypical symptoms,normal initial biomarkers of myocardial necrosis,and normal or nondiagnostic electrocardiograms(ECGs).Although cardiac CT allows for assessments of coronary artery stenosis as well as myocardial perfusion defect in patients with suspected ACS,it requires ECG gating and is usually performed with high-performance multislice CT for highly probable ACS patients.However,several recent reports have stated that ACS is detectable by myocardial perfusion defects even on routine non-ECG-gated contrast-enhanced CT.A growing number of contrast-enhanced CT scans are now being performed in emergency departments in search of pathologies responsible for a patient’s presenting symptoms.In order to avoid inappropriate management for this life-threatening event,clinicians should be aware that myocardial perfusion defect is more commonly detectable even on routine non-ECG-gated contrast-enhanced CT performed in search of other pathologies.

Comparison of computed tomography and magnetic resonance imaging for the detection of mandibular condylar osteochondroma

Objective The purpose of this study was to compare computed tomography(CT) and magnetic resonance imaging(MRI) for the detection of mandibular condylar osteochondroma.Methods Preoperative CT and MRI of 33 patients with unilateral condylar osteochondroma were reviewed. The morphology, location, continuity with the parent bone, cartilage cap, perichondrium of tumors, and changes in soft and hard tissues adjacent to the lesions were investigated by two reviewers. Data were analyzed using Mc Nemar test. A P value < 0.05 was considered significant.Results Among the 33 condylar osteochondromas, 11 were of the diffuse type, 10 were of the sessile type, and 12 were of the pedunculated type. Continuity with the cortex and marrow of the host condyle was observed on both CT and MRI. Both modalities had identical detection rates of surface reconstruction of the temporal bone joint, condylar dislocation, and pseudarthrosis formation. However, MRI showed significantly higher detection rates of the cartilage cap and perichondrium than CT(P < 0.05). Furthermore, MRI showed ipsilateral and contralateral temporo-mandibular joint(TMJ) disc displacement in 4 cases and 6 cases, respectively, and ipsilateral and contralateral TMJ effusion in 20 cases and 14 cases, respectively.Conclusion CT can intuitively display the morphology and spatial location of condylar osteochondromas through three-dimensional reconstruction. MRI may be superior to CT in the detection of cartilage cap, perichondrium of the condylar osteochondroma, and changes in the TMJ and adjacent soft tissues.

Qualitative visual trichotomous assessment improves the value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in predicting the prognosis of diffuse large B-cell lymphoma

Introduction:Fluorine-18 fluorodeoxyglucose(18F-FDG)positron emission tomography/computed tomography(PET/CT)is a powerful tool for monitoring the response of diffuse large B-cell lymphoma(DLBCL)to therapy,but the criteria to interpret PET/CT results remain under debate.We investigated the value of post-treatment PET/CT in predicting the prognosis of DLBCL patients when interpreted according to qualitative visual trichotomous assessment(QVTA)criteria compared with the Deauvil e criteria.Methods:In this retrospective study,final PET/CT scans of DLBCL patients treated with rituximab-based regimens between October 2005 and November 2010 were interpreted using the Deauvil e and QVTA criteria.Survival curves were estimated using Kaplan-Meier analysis and compared using the log-rank test.Results:A total of 253 patients were enrol ed.The interpretation according to the Deauvil e criteria revealed that 181patients had negative PET/CT scan results and 72 had positive results.The 3 year overal survival(OS)rate was significantly higher in patients with negative scan results than in those with positive results(91.6%vs.57.5%,P<0.001).The72 patients with positive scan results according to the Deauville criteria were divided into two groups by the interpretation according to the QVTA criteria:29 had indeterminate results,and 43 had positive results.The 3 year OS rate was significantly higher in patients with indeterminate scan results than in those with positive results(91.2%vs.33.5%,P<0.001)but was similar between patients with negative and indeterminate scan results(91.6%vs.91.2%,P=0.921).Conclusions:Compared with the Deauvil e criteria,using the QVTA criteria for interpreting post-treatment PET/CT scans of DLBCL patients is likely to reduce the number of false positive results.The QVTA criteria are feasible for therapeutic outcome evaluation and can be used to guide risk-adapted therapy.

Assessment of Organ Dose by Direct and Indirect Measurements for a Wide Bore X-Ray Computed Tomography Unit That Used in Radiotherapy

The aim of this study was to investigate the organ doses of patients undergoing computed tomography (CT) examination using the wide bore General Electric (GE) “Light Speed RT” unit. The head, chest and pelvic regions of the Rando-phantom were scanned with 120 kV, 200 mA, and 2.5 mm slice thickness for helical and axial modes. Thermoluminescent Dosimeter (TLD) pairs were used for the dosimetry of 10 organs. TL-counts were converted to dose by using CTDIcenter dose on CT-phantom. For the calculation of the organ doses, the ImPACT software was utilized by entering CTDIair (100 mAs) in small and large field of view (26.43 and 21.17 mGy respectively). The in-field dose ranges in helical and axial modes were 64.3 - 38 mGy and 47.6 - 19.7 mGy in head, 48.3 - 14.1 mGy and 34.1 - 10 mGy in chest, 28.4 - 10.2 mGy and 21 - 8.5 mGy in pelvic, respectively. The organ doses from software and TLD were compared and tailored as the in-field and the out-field radiation. First results showed that the organ dose was relatively higher in the helical mode on both direct and indirect measurement. The in-field organ dose differences between TLD and software were seen. In helical and axial modes, the dose differences ranged from +1 to +13.3 and -8.3 to +9.6 mGy for head exam, +1.1 to +15.3 and +0.3 to +9.1 mGy for chest, and -21.7 to +1.9 and -15.5 to +1.8 mGy for pelvic. The availability of this program for organ dose calculations by measuring CTDIair value for CT device used in the radiotherapy would be considered valuable.

Impact of random and scattered coincidences from outside of field of view on positron emission tomography/computed tomography imaging with different reconstruction protocols

Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.

Conception the Fluid Flow Behavior within Oil Reservoir Rock by Using Computed Tomography(CT)Scan

The behavior of fluid flow has been studied during the different flow media over the past decades.In addition,the behavior of the flow of fluid through porous media has garnered much research interest.This paper sheds light on fissured rocks of oil reservoir media(as one of the porous media domain),and the effect of these fissured on fluid flow.In this article,the Finite Volume Method(FVM)has been used to visualize the behavior of single-phase fluid flow in an actual core according to the dual-porosity dual permeability model.The study was conducted in two parts,the first was the image processing for one of the real oil reservoir fractured rock images,where the image was processed and simulated by ANSYS-CFX software,and the results showed a complete visualizing of the fluid behavior during this domain.As for the other side,a simulation of a real reservoir rock belonging to the Al-Nour field in Iraq/Misan was made.The X-ray Computed Tomography(CT)scan has been used to convert the real fractured core to a dynamic domain.ANSYS-CFX program has been used and the results illustrated the pressure counter,the velocity counter,the velocity streamline,and the velocity vectors for the studied model in three dimensions.A comparison was made between the productivity index for fractured and non-fractured rock and the results explained that the presence of fracture can improve the productivity index to about 5.74%.

优化双下肢动脉能谱CT血管造影成像方案

目的优化双下肢动脉能谱CT血管造影(CTA)成像方案。方法回顾性分析30例疑诊双下肢动脉硬化性闭塞症(ASO)患者双下肢动脉能谱CTA资料,经重建获得40~80 keV(间隔5 keV)单能量(共9种)及100 kVp混合能量图像,对比双下肢动脉在不同图像中的CT值、噪声(SD)值、信噪比(SNR)及对比度噪声比(CNR);针对50、60 keV单能量和100 kVp混合能量图像质量及血管节段的可诊断性进行主观评估,观察40、45、50、60 keV单能量和100 kVp混合能量图像的自动去骨能力。结果40~80 keV范围内,随keV升高,各动脉在图像中的CT值、SD值、SNR及CNR均逐渐降低。相比100 kVp,腘动脉(PA)及其近端动脉的CT值、CNR及SNR均在40~55 keV图像中升高(P均<0.05);50~55 keV图像中SD值升高(P均<0.05),而60 keV图像中差异无统计学意义(P>0.05)。50及60 keV图像质量主观评分及可诊断动脉节段数与100 kVp差异均无统计学意义(P均>0.05)。PA以远节段的SNR及CNR在各单能量图像及100 kVp图像中差异均无统计学意义,其CT值在40~45 keV图像中、SD在40 keV图像中均高于100 kVp(P均<0.05),但SD在45 keV与100 kVp图像中差异无统计学意义(P>0.05);50 keV图像中,PA以远节段图像质量主观评分及可诊断节段数均高于60 keV及100 kVp(P均<0.05)。40 keV图像对9例(9/30,30.00%)、45 keV图像对6例(6/30,20.00%)不能自动去骨,50及60 keV、100 kVp对30例(30/30,100%)均可自动去骨。结论行双下肢动脉能谱CTA时,对PA及其近端节段以60 keV单能量成像较佳,对其以远或双下肢全程则以50 keV单能量成像较佳。

基于增强CT影像组学预测食管鳞癌淋巴血管侵犯状态的价值

目的:探讨基于增强CT影像组学预测食管鳞癌(ESCC)淋巴血管侵犯(LVI)的价值。方法:回顾性搜集行根治性切除术并经术后病理证实的224例食管鳞癌患者,其中包括66例LVI阳性和158例LVI阴性患者。所有患者均在术前2周内进行胸部增强CT扫描。将入组的患者按照7:3的比例随机分为训练集和测试集。使用3D Slicer软件逐层勾画全肿瘤感兴趣区(ROI),采用Python软件的Pyradiomics包提取肿瘤组织的影像组学特征,建立影像组学模型用于预测食管鳞癌的LVI状态并进行验证。采用受试者工作特征(ROC)曲线的曲线下面积(AUC)、敏感度、特异度、准确度、阳性预测值和阴性预测值来评价影像组学模型的诊断效能,使用校准曲线评价影像组学模型在训练集和测试集中的拟合程度。使用决策曲线分析(DCA)评价影像组学模型的临床应用价值。结果:从全肿瘤ROI中提取了1130个组学特征,经过筛选最终保留了7个影像组学特征,并使用多因素logistic回归建立影像组学预测模型。在训练集中,影像组学模型预测LVI的AUC值为0.930,敏感度为0.851,特异度为0.919,准确度为0.899,阳性预测值为0.816,阴性预测值为0.936;在测试集中,AUC值为0.897,敏感度为0.789,特异度为0.787,准确度为0.788,阳性预测值为0.600,阴性预测值为0.902。校准曲线显示影像组学模型在训练集及测试集中的预测概率与实际概率的一致性良好。DCA曲线显示影像组学模型具有良好的临床应用价值。结论:基于增强CT构建的影像组学模型,能够在术前有效预测食管鳞癌的LVI状态。

人工智能诊断系统及CT无创血流储备分数在评估高海拔地区 冠脉临界病变中的应用

目的探讨基于冠状动脉CT血管成像(CCTA)的人工智能(AI)诊断系统及CT无创血流储备分数(CT-FFR)在评估高海拔地区冠状动脉临界病变结构及功能学中的应用价值。方法前瞻性收集2022年1月~2023年10月青海大学附属医院冠心病临界病变患者164例,按居住地海拔进行分组,其中2000~3000m为A组(n=83),3000m以上为B组(n=81),再将两组患者按冠脉狭窄程度细分为50%~60%亚组(n=84)和61%~70%亚组(n=80)。将患者冠状动脉CT血管成像数据导入AI辅助诊断及CT-FFR测量系统,以冠脉造影及冠脉传统血流储备分数(FFR)为金标准,分别评价AI及CT-FFR在高海拔地区冠脉临界病变诊断中的应用。结果以FFR为金标准,CT-FFR与FFR的一致性为83.75%。B组钙化斑块、易损斑块高于A组(P=0.037、0.020);B组冠状动脉多支病变、61%~70%狭窄程度发生率均高于A组(P<0.05);A组、B组在61%~70%亚组钙化斑块、易损斑块发生率均高于50%~60%亚组(P<0.05)。B组CT-FFR值低于A组(0.76±0.04 vs 0.88±0.05,P<0.01);A、B两组在61%~70%亚组CT-FFR值≤0.80、<0.70的发生率高于50%~60%亚组(P<0.05)。结论AI诊断系统及CT-FFR对评估高海拔地区冠状动脉临界病变的结构特征及血流动力学改变的结果与冠脉造影、FFR一致性高,具有较高的诊断敏感度和特异度。

定量CT评价胸椎骨密度及与年龄相关的骨丢失

目的探讨胸椎定量CT(QCT)测量骨密度及骨丢失率的可行性。方法选取因健康体检及急腹症行全腹部CT扫描的患者708例,使用QCT软件测量T10-L3椎体骨密度。将受检者按每10岁为一个年龄段分组。计算每个年龄组的胸椎及腰椎骨密度,并计算各组别的峰值骨密度及骨丢失率。胸椎与腰椎骨密度及其与年龄的相关性采用Pearson相关分析。结果男性、女性骨密度峰值均在20~29岁年龄组,30岁以后胸腰椎骨密度开始不同程度减低,80~89岁女性胸椎及腰椎累计骨丢失率分别为60.61%及61.34%,而男性分别为44.45%及49.35%。男性与女性胸腰椎骨密度均与年龄呈负相关(P<0.01)。胸椎与腰椎骨密度呈正相关(男性r=0.96、女性r=0.98,P<0.01)。结论胸椎及腰椎QCT均能准确地显示不同年龄组的骨密度及骨丢失情况,胸椎QCT可以作为评价和监测骨丢失的一种方法。

超声与CT技术在高原地区藏族人群肺结核疾病诊断价值的比较研究

目的:比较研究高原地区藏族人群肺结核患者超声与CT影像特点及诊断价值。方法:选择2022年5月至2023年11月青海省中医院收治的100例高原地区藏族人群肺结核患者,所有患者均行超声与CT检查,动态观察高原地区肺结核患者肺部病变的超声影像学特点,比较超声与CT检查对高原地区藏族人群肺结核的诊断效果。结果:超声与CT检查高原地区藏族人群肺结核的阳性检出率比较,差异无统计学意义(χ^(2)=0.053,P>0.05)。超声诊断的灵敏度为97.80%、特异度为44.44%、约登指数42.24%,CT诊断的灵敏度为96.77%、特异度为42.86%、约登指数39.63%,差异无统计学意义(χ^(2)=0.184,0.004,0.272,P>0.05)。超声与CT检查高原地区藏族人群肺结核病变肺叶分布检出率比较,差异无统计学意义(χ^(2)=2.011,P>0.05)。超声与CT检查对高原地区藏族人群肺结核患者肺不张、空洞、钙化、伴随胸水的检出率比较,差异无统计学意义(χ^(2)=0.190,0.197,0.190,0.046,P>0.05)。结论:超声检查的阳性检出率、病变肺叶分布检出率和肺不张、空洞、钙化、伴随胸水等肺结核并发或伴随征象检出率均与CT检查无差异,而高原地区医疗资源匮乏,缺少大型检查设备,应用超声检查进行肺结核普查及初步诊断,对缺少CT设备或受电力影响的高原地区更适合。

疑诊原发性甲状旁腺功能亢进症的患者术前^(99m)Tc-MIBI SPECT/CT显像结果的影响因素分析

目的探讨疑诊原发性甲状旁腺功能亢进症(primary hyperparathyroidism,PHPT)的患者术前^(99m)Tc-甲氧基异丁基异腈(methoxyisobutylisonitrile,MIBI)单光子发射计算机断层扫描/计算机断层扫描(single-photon emission computed tomography/computed tomography,SPECT/CT)(以下简称MIBI SPECT/CT)显像结果的影响因素。方法将2019年1月至2023年8月于首都医科大学附属北京朝阳医院疑诊PHPT并在术前完善甲状旁腺MIBI SPECT/CT显像的257例患者作为研究对象。比较MIBI SPECT/CT显像阳性组和阴性组的实验室检查、病理特征及影像特征。采用多因素Logistic回归分析MIBI SPECT/CT显像结果的影响因素。结果单因素分析显示,与阴性组相比,血清总钙、血清甲状旁腺激素(parathyroid hormone,PTH)、碱性磷酸酶(alkaline phosphatase,ALP)水平在阳性组显著升高(P<0.05);病灶的病理类型、最大径、体积及位置在两组间差异有统计学意义(P<0.05)。多因素Logistic回归分析显示,术前血清PTH水平、病灶病理类型、位置及最大径与MIBI SPECT/CT显像结果阳性显著相关(P<0.05)。结论疑诊PHPT患者术前MIBI SPECT/CT显像结果受多重因素影响,术前血清PTH水平、病灶病理类型、位置及最大径是MIBI SPECT/CT显像结果的独立影响因素。

不同扫描延迟技术在大螺距冠状动脉CT血管成像中的对比研究

目的:比较2种扫描延迟技术在大螺距冠状动脉CT血管成像(CCTA)中运用的可行性。方法:前瞻性收集临床疑似冠心病行CCTA检查的心率≤60次/分病人58例,随机分为团注跟踪组31例和测试团注组27例。分别在主动脉根部、左主干、左前降支近段、左回旋支近段、右冠状动脉近段、肺动脉、左心房和左心室选取感兴趣区,测量CT值和噪声,计算信噪比、对比噪声比、左房室比、左室肺动脉比和主肺动脉比,评估2组图像质量,比较2组客观和主观评价指标差异。结果:2组各目标血管强化CT值、信噪比和对比噪声比差异均无统计学意义(P>0.05),团注跟踪组肺动脉CT值、左房室比、左室肺动脉比和主肺动脉比均明显低于测试团注组(P<0.01)。2组主观图像质量评分差异无统计学意义(P>0.05)。团注跟踪组CT剂量指数、剂量长度乘积、有效辐射剂量、注射流率和对比剂量均低于测试团注组(P<0.05~P<0.01)。结论:大螺距CCTA采用团注跟踪技术,可提高血管强化CT值并能降低辐射剂量和对比剂用量。

基于不同管电压的人工智能重建算法对胸部体模CT扫描图像质量和辐射剂量的影响研究

目的:基于成年男性仿真胸部体模(PH-N1)CT扫描,探究不同管电压结合人工智能(AI)重建(CI)算法对胸部体模CT扫描图像质量和辐射剂量的影响。方法:采用512层超高端CT分为4种管电压对体模进行扫描,分别为70 kV、80 kV、100 kV和120 kV,对不同管电压的CT扫描图像采用10%、30%、50%、70%和90%CI算法重建1 mm薄层图像,比较4组扫描的容积剂量指数(CTDIvol)和剂量-长度乘积(DLP)。测量图像主动脉、腹壁脂肪及竖棘肌的CT值、标准偏差(SD)值,由两名5年以上工作经验的高年资诊断医师独立双盲的对图像质量进行5分制评估,并行Kappa一致性检验。采用单因素方差分析比较图像目标组织的CT值、SD值差异。采用Friedman秩和检验比较组间主观图像质量的差异。结果:4种不同管电压的CTDIvol和DLP比较,差异有统计学意义(F=1855.617、3996.118,P<0.05)。在70 kV管电压下,10%、30%、50%、70%和90%CI算法重建的主动脉、腹壁脂肪及竖棘肌的CT值比较,差异均无统计学意义(P>0.05),而SD值差异均有统计学意义(F=32.267、53.327、14.873,P<0.05)。在90%权重的CI算法重建4种不同管电压下,主动脉、腹壁脂肪及竖棘肌的CT值随着管电压的降低,CT值逐渐降低,差异有统计学意义(F=139.899、2563.93、219.231,P<0.05)。两名诊断医师对各组图像的主观评分一致性较好(Kappa=0.712~0.869)。结论:CI算法在70 kV管电压下90%权重的CI算法重建图像与80 kV、90 kV、120 kV图像相比,可以明显降低辐射剂量,同时图像具有良好信噪比。

脊椎骨内神经鞘瘤的CT、MRI表现(附11例报道及文献复习)

目的探讨脊椎骨内神经鞘瘤(Intraosseous Schwannoma,IOS)的特征性影像学表现,以与其他脊椎溶骨性病变区别开。方法回顾性分析上海交通大学医学院附属第九人民医院经手术病理证实的脊椎IOS的临床资料及CT、MRI等影像学资料。该文收集了11例脊椎IOS患者,其中男性7例,女性4例,年龄23~74岁[平均年龄(51±17)岁]。所有患者均行CT和MRI检查。由两名高年资骨关节系统放射科医师对所有影像学征象进行评估,并复习了近几年来文献报告的脊椎IOS影像学征象。结果病变累及部位包括颈椎3例(3/11,27.3%),胸椎1例(1/11,9.1%),腰椎5例(5/11,45.5%),腰骶椎2例(2/11,18.2%),最大径(5.8±2.85)cm,形态均为不规则形。CT显示偏心性膨胀性溶骨性骨质破坏,密度不均匀,平扫CT值为(43.0±11.55)HU。增强后不均匀轻度强化,CT值为(70.3±12.22)HU,病灶边界清晰,有硬化缘,未见骨膜反应,病灶易沿着椎间孔向椎管内外延伸。在MRI上,与肌肉组织相比,病灶在T1WI上呈等稍低信号,在T2WI上呈混杂稍高信号,压脂后呈混杂高信号,DWI未见弥散受限,ADC值为(1.25±0.176)×10-3mm2/s,增强后不均匀明显强化,时间-信号强度曲线为I型,7例患者病灶内发生囊性变。结论脊椎IOS是一种罕见的良性肿瘤,影像学表现具有一定的特征性,在鉴别诊断边界清晰的具有异质性的脊椎溶骨性病变时应予以考虑。

叠片式锂离子电池在线快速CT检测技术

锂离子电池行业对电池质量检测方法的需求日益增长。针对叠片式电池X射线检测方式存在的图像遮挡和不能直接测量x、y方向包覆量的问题,提出一种快速计算机断层扫描(CT)定向重建技术。通过2维(2D)定位切片位置,重建3维(3D)体素数据的两张x、y方向切片图像,再进行正负极顶点定位,实现对包覆量的直接精确计算。使用所提方法的快速CT检测设备与传统2D检测设备相比,误判率可降低2~3个百分点。

宽体探测器CT血管造影与超声心动图对小儿先天性心脏病的诊断效能

目的探讨宽体探测器CT血管造影(computer tomography angiography,CTA)与超声心动图(ultrasound cardiogram,UCG)在小儿先天性心脏病(congenital heart disease,CHD)的诊断效能。方法回顾性分析2019-08/2023-09月作者医院收治的65例疑似CHD患儿的影像学资料,所有患儿均行心脏CTA及UCG检查。对两种检查方式的图像质量进行主观评价并比较其差异;以手术或数字减影血管造影(digital subtraction angiography,DSA)为“金标准”,对比两种检查方式在诊断CHD的灵敏度、特异度、阳性预测值、阴性预测值及准确率的差异,并应用Kappa检验比较与“金标准”结果的一致性;采用受试者工作特征(receiver operating characteristic,ROC)曲线分析两种检查方式对小儿CHD的诊断效能。结果CTA诊断小儿CHD心外畸形图像质量主观评分明显高于UCG,二者比较差异具有统计学意义(P<0.05),心内畸形图像质量主观评分二者比较差异无统计学意义(P>0.05)。两名医师对图像质量主观评分的一致性较好(κ=0.802)。CTA、UCG诊断小儿CHD心内畸形准确率比较差异无统计学意义(P>0.05);CTA诊断小儿CHD心外畸形准确率为96.43%,显著高于UCG 50.00%,组间比较差异具有统计学意义(P<0.05)。CTA诊断小儿CHD的灵敏度、特异度、阳性预测值、阴性预测值及准确率分别为90.00%、60.00%、96.43%、33.33%及87.69%,与手术或DSA结果一致性较好(κ=0.766);UCG诊断CHD的灵敏度、特异度、阳性预测值、阴性预测值及准确率分别为83.33%、20.00%、92.59%、9.09%及79.81%,与手术或DSA结果一致性一般(κ=0.522)。CTA、UCG两种检查方式诊断小儿CHD的灵敏度、特异度、阴性预测值及准确率差异比较均有统计学意义(P均<0.05)。ROC曲线分析结果显示,CTA与UCG诊断小儿CHD的曲线下面积(area under the cure,AUC)分别为0.853和0.773,二者比较差异有统计学意义(P<0.05)。结论宽体探测器CTA在小儿CHD心外畸形方面的诊断效能优于UCG,而在心内畸形方面稍差,因此建议二者联合检查,诊断价值更高。