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.

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.

High-resolution computed tomography findings in humoral primary immunodeficiencies and correlation with pulmonary function tests

AIM To compare high-resolution computed tomography(HRCT) findings between humoral primary immunodeficiencies(hPIDs) subtypes; to correlate these findings to pulmonary function tests(PFTs).METHODS We retrospectively identified 52 consecutive adult patients with hPIDs who underwent 64-row HRCT and PFTs at the time of diagnosis. On a per-patient basis, an experienced radiologist recorded airway abnormalities(bronchiectasis,airway wall thickening, mucus plugging, tree-in-bud, and air-trapping) and parenchymal-interstitial abnormalities(consolidations, ground-glass opacities,linear and/or irregular opacities, nodules, and bullae/cysts) found on HRCT.The chi-square test was performed to compare the prevalence of each abnormality among patients with different subtypes of hPIDs. Overall logistic regression analysis was performed to assess whether HRCT findings predicted obstructive and/or restrictive PFTs results(absent-to-mild vs moderate-tosevere).RESULTS Thirty-eight of the 52 patients with hPIDs showed common variable immunodeficiency disorders(CVID), while the remaining 14 had CVID-like conditions(i.e., 11 had isolated IgG subclass deficiencies and 3 had selective IgA deficiencies). The prevalence of most HRCT abnormalities was not significantly different between CVID and CVID-like patients(P > 0.05), except for linear and/or irregular opacities(prevalence of 31.6% in the CVID group and 0 in the CVID-like group; P = 0.0427). Airway wall thickening was the most frequent HRCT abnormality found in both CVID and CVID-like patients(71% of cases in both groups). The presence of tree-in-bud abnormalities was an independent predictor of moderate-to-severe obstructive defects at PFTs(Odds Ratio, OR, of 18.75, P < 0.05), while the presence of linear and/or irregular opacities was an independent predictor of restrictive defects at PFTs(OR = 13.00; P < 0.05).CONCLUSION CVID and CVID-like patients showed similar HRCT findings. Tree-in-bud and linear and/or irregular opacities predicted higher risks of, respectively,obstructive and restrictive defects at PFTs.

Values of high-resolution computed tomography and pulmonary function tests in managements of patients with chronic hepatitis C virus infection

AIM:To investigate pulmonary involvement via pulmonary function tests (PFT) and high-resolution computed tomocjraphy (HRCT) in patients with chronic hepatitis C virus (HCV) infection. METHODS:Thirty-four patients with chronic HCV infection without diagnosis of any pulmonary diseases and 10 healthy cases were enrolled in the study,PFT and HRCT were performed in all cases. RESULTS:A decrease lower than 80% of the predicted value was detected in vital capacity in 9/34 patients,in forced expiratory volume in one second in 8/34 patients,and in forced expiratory flow 25-75 in 15/34 patients,respectively.Carbon monoxide diffusing capacity (DLCO) was decreased in 26/34 patients.Findings of interstitial pulmonary involvement were detected in the HRCT of 16/34 patients.Significant difference was found between controls and patients with HCV infection in findings of HRCT (X^2=4.7,P=0.003).Knodell histological activity index (KHAI) of 28/34 patients in whom liver biopsy was applied was 9.0±4.7.HRCT findings,PFT values and DLCO were not affected by KHAI in patients with HCV infection.In these patients,all the parameters were related with age. CONCLUSION:We suggest that chronic hepatitis C virus infection may cause pulmonary interstitial involvement without evident respiratory symptoms.

Evaluation of response to gemcitabine plus cisplatin-based chemotherapy using positron emission computed tomography for metastatic bladder cancer

BACKGROUND The purpose of the present study was to examine retrospectively the contribution of 18Fluorodeoxyglucose positron emission tomography computed tomography(18FDG-PET/CT)to the evaluation of response to first-line gemcitabine plus cispla-tin-based chemotherapy in patients with metastatic bladder cancer.AIM To evaluate the response to Gemcitabine plus Cisplatin-based chemotherapy using 18FDG-PET/CT imaging in patients with metastatic bladder cancer.METHODS Between July 2007 and April 2019,79 patients underwent 18FDG-PET/CT imaging with the diagnosis of Metastatic Bladder Carcinoma(M-BCa).A total of 42 pa-tients(38 male,4 female)were included in the study,and all had been admi-nistered Gemcitabine plus Cisplatin-based chemotherapy.After completion of the therapy,the patients underwent a repeat 18FDG-PET/CT scan and the results were compared with the PET/CT findings before chemotherapy according to European Organisation for the Research and treatment of cancer criteria.Mean age was 66.1 years and standard deviation was 10.7 years(range:41–84 years).RESULTS Of the patients,seven(16.6%)were in complete remission,17(40.5%)were in partial remission,six(14.3%)had a stable disease,and 12(28.6%)had a pro-gressive disease.The overall response rate was 57.1 percent.CONCLUSION 18FDG-PET/CT can be considered as a successful imaging tool in evaluating response to first-line chemotherapy for metastatic bladder cancer.Anatomical and functional data obtained from PET/CT scans may be useful in the planning of secondline and thirdline chemotherapy.

Radiation Dose Survey of Pediatric Chest Computed Tomography Examinations: A Local Diagnostic Reference Levels Approach to Patient Safety

Objectives: The aim of this work was to initially establish both age and weight driven pediatric diagnostic reference levels (DRLs) for chest computed tomography (CT) examinations performed at tertiary care medical institution. Another aim was to compare the presented data with internationally published ones. This initial data shall serve as basis for establishing a national DRLs values for pediatric diagnostic CT examinations. Methods: Dosimetric indexes were collected for the chest examination for 93 patients during the past 2 years in a tertiary care medical city. Results: The results are within and below the international reported levels for chest CT in several countries. Conclusion: Continuous monitoring of the radiation doses received by the patients in computed tomography is continuous and ongoing process in order to ensure compliance and to optimize clinical imaging protocols. More extensive data acquisition and analysis are required to allow better understanding of the contributing factors leading to less patient radiation dose while preserving the clinical image quality. .

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.

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。

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。

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。

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。