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.

Evaluation of human epidermal growth factor receptor 2 status of breast cancer using preoperative multidetector computed tomography with deep learning and handcrafted radiomics features

Objective:To evaluate the human epidermal growth factor receptor 2(HER2)status in patients with breast cancer using multidetector computed tomography(MDCT)-based handcrafted and deep radiomics features.Methods:This retrospective study enrolled 339 female patients(primary cohort,n=177;validation cohort,n=162)with pathologically confirmed invasive breast cancer.Handcrafted and deep radiomics features were extracted from the MDCT images during the arterial phase.After the feature selection procedures,handcrafted and deep radiomics signatures and the combined model were built using multivariate logistic regression analysis.Performance was assessed by measures of discrimination,calibration,and clinical usefulness in the primary cohort and validated in the validation cohort.Results:The handcrafted radiomics signature had a discriminative ability with a C-index of 0.739[95%confidence interval(95%CI):0.661-0.818]in the primary cohort and 0.695(95%CI:0.609-0.781)in the validation cohort.The deep radiomics signature also had a discriminative ability with a C-index of 0.760(95%CI:0.690-0.831)in the primary cohort and 0.777(95%CI:0.696-0.857)in the validation cohort.The combined model,which incorporated both the handcrafted and deep radiomics signatures,showed good discriminative ability with a C-index of 0.829(95%CI:0.767-0.890)in the primary cohort and 0.809(95%CI:0.740-0.879)in the validation cohort.Conclusions:Handcrafted and deep radiomics features from MDCT images were associated with HER2 status in patients with breast cancer.Thus,these features could provide complementary aid for the radiological evaluation of HER2 status in breast cancer.

Tumor characteristics of ductal carcinoma in situ of breast visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography: Results from a retrospective study

AIM To clarify clinicopathological features of ductal carcinoma in situ(DCIS) visualized on [F-18] fluorodeoxyglucosepositron emission tomography/computed tomography(FDG-PET/CT).METHODS This study retrospectively reviewed 52 consecutive tumors in 50 patients with pathologically proven pure DCIS who underwent [F-18] FDG-PET/CT before surgery. [F-18] FDG-PET/CT was performed after biopsy in all patients. The mean interval from biopsy to [F-18] FDGPET/CT was 29.2 d. [F-18] FDG uptake by visual analysis and maximum standardized uptake value(SUVmax) was compared with clinicopathological characteristics.RESULTS[F-18] FDG uptake was visualized in 28 lesions(53.8%) and the mean and standard deviation of SUVmax was 1.63 and 0.90. On univariate analysis, visual analysis and the SUVmax were associated with symptomatic presentation(P = 0.012 and 0.002, respectively), palpability(P = 0.030 and 0.024, respectively), use of core-needle biopsy(CNB)(P = 0.023 and 0.012, respectively), ultrasound-guided biopsy(P = 0.040 and 0.006, respectively), enhancing lesion ≥ 20 mm on magnetic resonance imaging(MRI)(P = 0.001 and 0.010, respectively), tumor size ≥ 20 mm on histopathology(P = 0.002 and 0.008, respectively). However, [F-18] FDG uptake parameters were not significantly associated with age, presence of calcification on mammography, mass formation on MRI, presence of comedo necrosis, hormone status(estrogen receptor, progesterone receptor and human epidermal growth factor receptor-2), and nuclear grade. The factors significantly associated with visual analysis and SUVmax were symptomatic presentation(P = 0.019 and 0.001, respectively), use of CNB(P = 0.001 and 0.031, respectively), and enhancing lesion ≥ 20 mm on MRI(P = 0.001 and 0.049, respectively) on multivariate analysis.CONCLUSION Although DCIS of breast is generally non-avid tumor, symptomatic and large tumors(≥ 20 mm) tend to be visualized on [F-18] FDG-PET/CT.

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.

Comparisons between glucose analogue 2-deoxy-2-(^(18)F)fluoro-D-glucose and ^(18)F-sodium fluoride positron emission tomography/computed tomography in breast cancer patients with bone lesions

AIM: To compare 2-deoxy-2-(18F)fluoro-D-glucose(18F-FDG) and 18F-sodium (18F-NaF) positron emission tomography/computed tomography (PET/CT) accuracy in breast cancer patients with clinically/radiologically suspected or known bone metastases.METHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical/biochemical or radiological suspicion of bone metastatic disease underwent 18F-FDG and 18F-fluoride PET/CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity (Se), specificity (Sp), overall accuracy, positive and negative predictive values, error rate, and Youden’s index. McNemar’s χ2 test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyses were computed on a patient basis, and then on a lesion basis, with consideration ofthe density of independent lesions on the co-registered CT (sclerotic, lytic, mixed, no-lesions) and the divergent site of disease (skull, spine, ribs, extremities, pelvis). The impact of adding 18F-NaF PET/CT to the work-up of patients was also measured in terms of change in their management due to 18F-NaF PET/CT findings.RESULTS: The two imaging methods of 18F-FDG and 18F-fluoride PET/CT were significantly different at the patient-based analysis: Accuracy was 86.7% and 84.4%, respectively (McNemar’s χ2 = 6.23, df = 1, P = 0.01). Overall, 244 bone lesions were detected in our analysis. The overall accuracy of the two methods was significantly different at lesion-based analysis (McNemar’s χ2 = 93.4, df = 1, P < 0.0001). In the lesion density-based and site-based analysis, 18F-FDG PET/CT provided more accurate results in the detection of CT-negative metastasis (P < 0.002) and vertebral localizations (P < 0.002); 18F-NaF PET/CT was more accurate in detecting sclerotic (P < 0.005) and rib lesions (P < 0.04). 18F-NaF PET/CT led to a change of management in 3 of the 45 patients (6.6%) by revealing findings that were not detected at 18F-FDG PET/CT.CONCLUSION: 18F-FDG PET/CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of 18F-NaF PET/CT in the general population of breast cancer patients. However, the extremely high sensitivity of 18F-fluoride PET/CT can exploit its diagnostic potential in specific clinical settings (i.e., small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative 18F-FDG PET and conventional imaging).

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.

Preoperative [18]fluorodeoxyglucose-positron emission tomography/computed tomography in early stage breast cancer: Rates of distant metastases

AIM To investigate rates of distant metastases(DM) detected with [18]fluorodeoxyglucose-positron emissiontomography/computed tomography(^(18)FDG-PET/CT) in early stage invasive breast cancer.METHODS We searched the English language literature databases of PubM ed, EMBASE, ISI Web of Knowledge, Web of Science and Google Scholar, for publications on DM detected in patients who had ^(18)FDG-PET/CT scans as part of the staging for early stages of breast cancer(stage Ⅰ?and Ⅱ), prior to or immediately following surgery. Reports published between 2011 and 2017 were considered. The systematic review was conducted according to the PRISMA guidelines.RESULTS Among the 18 total studies included in the analysis, the risk of DM ranged from 0% to 8.3% and 0% to 12.9% for stage Ⅰ?and Ⅱ invasive breast cancer, respectively. Among the patients with clinical stage Ⅱ, the rate of occult metastases diagnosed by ^(18)FDG-PET/CT was 7.2%(range, 0%-19.6%) for stage ⅡA and 15.8%(range, 0%-40.8%) for stage ⅡB. In young patients(< 40-yearold), ^(18)FDG-PET/CT demonstrated a higher prevalence of DM at the time of diagnosis for those with aggressive histology(i.e., triple-negative receptors and poorly differentiated grade).CONCLUSION Young patients with poorly differentiated tumors and stage ⅡB triple-negative breast cancer may benefit from ^(18)FDG-PET/CT at initial staging to detect occult DM prior to surgery.

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。

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。

基于定量CT身体组分、^(18)F-FDG PET/CT显像预测手术联合新辅助化疗治疗早期乳腺癌预后的价值

目的 分析定量CT (QCT)身体组分、^(18)F-氟脱氧葡萄糖正电子发射型计算机断层显像(^(18)F-FDG PET-CT)对手术联合新辅助化疗(NAC)治疗早期乳腺癌患者预后的预测效能,为临床治疗提供参考。方法 选取2020年3月至2022年10月于南阳市第二人民医院接受手术联合NAC治疗的82例早期乳腺癌患者纳入研究,在NAC前和化疗1、3个周期后检测记录QCT参数[L_(1)、L_(2)水平的皮下脂肪面积(SFA)、内脏脂肪面积(VFA)、骨密度(BMD)、L_(3)水平的椎旁肌肉面积(TMA)]、^(18)F-FDG PET/CT显像的最大标准摄取值(SUV_(max))、肿瘤代谢体积(MTV)。NAC结束后进行手术,随访12个月(失访2例),依据有无复发转移分为预后良好组43例和预后不良组37例,比较不同预后患者的QCT参数、^(18)F-FDG PET/CT显像指标,采用受试者工作特征(ROC)曲线获取曲线下面积(AUC)分析其对早期乳腺癌患者预后的预测效能。结果化疗1个周期后,预后良好组患者的SFA、BMD、VFA、MA水平分别为(45.23±4.07) cm^(2)、(128.97±26.53) mg/m^(2)、(78.07±6.69) cm^(2)、(37.36±5.74) cm^(2),明显高于预后不良组的(42.52±3.32) cm^(2)、(112.54±25.82) mg/m^(2)、(73.73±7.25) cm^(2)、(32.94±5.31) cm^(2),差异均有统计学意义(P<0.05);化疗3个周期后,预后良好组患者的SFA、BMD、VFA、MA水平分别为(40.95±3.92) cm^(2)、(113.55±15.87) mg/m^(2)、(73.59±6.17) cm^(2)、(32.67±4.98) cm^(2),明显高于预后不良组的(37.51±3.56) cm^(2)、(95.18±17.45) mg/m^(2)、(70.30±5.14) cm^(2)、(28.52±4.42) cm^(2),差异均有统计学意义(P<0.05);化疗1个周期后,预后良好组患者的SUV_(max)、MTV分别为5.43±1.25、(3.86±0.87)×10^(4)mm,明显低于预后不良组的6.04±1.07、(4.27±0.85)×10^(4)mm,差异均有统计学意义(P<0.05);化疗3个周期后,预后良好组患者的SUV_(max)、MTV分别为3.94±1.06、(2.61±0.70)×10^(4)mm,明显低于预后不良组的4.73±1.21、(3.05±0.93)×10^(4)mm,差异均有统计学意义(P<0.05);经ROC曲线分析结果显示,SFA、BMD、VFA、MA、SUV_(max)、MTV联合预测手术联合NAC治疗早期乳腺癌患者预后的AUC分别为0.898 (95%CI:0.809~0.954)、0.919 (95%CI:0.836~0.968)。结论 NAC过程中检测QCT参数、^(18)F-FDG PET/CT显像指标可预测手术联合NAC治疗早期乳腺癌患者的预后,联合预测的价值较高。

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。