Artificial intelligence software for assessing brain ischemic penumbra/core infarction on computed tomography perfusion:A real-world accuracy study

BACKGROUND With the increasingly extensive application of artificial intelligence(AI)in medical systems,the accuracy of AI in medical diagnosis in the real world deserves attention and objective evaluation.AIM To investigate the accuracy of AI diagnostic software(Shukun)in assessing ischemic penumbra/core infarction in acute ischemic stroke patients due to large vessel occlusion.METHODS From November 2021 to March 2022,consecutive acute stroke patients with large vessel occlusion who underwent mechanical thrombectomy(MT)post-Shukun AI penumbra assessment were included.Computed tomography angiography(CTA)and perfusion exams were analyzed by AI,reviewed by senior neurointerventional experts.In the case of divergences among the three experts,discussions were held to reach a final conclusion.When the results of AI were inconsistent with the neurointerventional experts’diagnosis,the diagnosis by AI was considered inaccurate.RESULTS A total of 22 patients were included in the study.The vascular recanalization rate was 90.9%,and 63.6%of patients had modified Rankin scale scores of 0-2 at the 3-month follow-up.The computed tomography(CT)perfusion diagnosis by Shukun(AI)was confirmed to be invalid in 3 patients(inaccuracy rate:13.6%).CONCLUSION AI(Shukun)has limits in assessing ischemic penumbra.Integrating clinical and imaging data(CT,CTA,and even magnetic resonance imaging)is crucial for MT decision-making.

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.

Computed tomography perfusion in differentiating portal hypertension: A correlation study with hepatic venous pressure gradient

BACKGROUND Hepatic venous pressure gradient(HVPG)is the gold standard for diagnosis of portal hypertension(PH),invasiveness and potential risks in the process of measurement limited its widespread use.AIM To investigate the correlation of computed tomography(CT)perfusion parameters with HVPG in PH,and quantitatively assess the blood supply changes in liver and spleen parenchyma before and after transjugular intrahepatic portosystemic shunt(TIPS).METHODS Twenty-four PH related gastrointestinal bleeding patients were recruited in this study,and all patients were performed perfusion CT before and after TIPS surgery within 2 wk.Quantitative parameters of CT perfusion,including liver blood volume(LBV),liver blood flow(LBF),hepatic arterial fraction(HAF),spleen blood volume(SBV)and spleen blood flow(SBF),were measured and compared before and after TIPS,and the quantitative parameters between clinically significant PH(CSPH)and non-CSPH(NCSPH)group were also compared.Then the correlation of CT perfusion parameters with HVPG were analyzed,with statistical significance as P<0.05.RESULTS For all 24 PH patients after TIPS,CT perfusion parameters demonstrated decreased LBV, increased HAF, SBV and SBF, with no statistical difference in LBF. Compared withNCSPH, CSPH showed higher HAF, with no difference in other CT perfusion parameters. HAFbefore TIPS showed positive correlation with HVPG (r = 0.530, P = 0.008), while no correlation wasfound in other CT perfusion parameters with HVPG and Child-Pugh scores.CONCLUSIONHAF, an index of CT perfusion, was positive correlation with HVPG, and higher in CSPH thanNCSPH before TIPS. While increased HAF, SBF and SBV, and decreased LBV, were found afterTIPS, which accommodates a potential non-invasive imaging tool for evaluation of PH.

Perihematomal Perfusion Typing and Spot Sign of Acute Intracerebral Hemorrhage with Multimode Computed Tomography: A Preliminary Study

Objective To explore the perihematomal perfusion typing and spot sign on computed tomography angiography(CTA) source images in order to assist in individualizing therapeutic decisions for patients with intracerebral hemorrhage by possibly forecasting perihematomal ischemia and hematoma enlargement. Methods We examined 58 patients with spontaneous intracerebral hemorrhage by computed tomography perfusion and CTA within 6 hours after symptom onset. Hematoma volumes were determined from non-contrast CT images and compared between first and second CT images. The perfusion of hematoma region and perihematoma region was evaluated for presence or absence of the perihematomal penumbra. Three kinds of perihematoma perfusion typing were defined according to the perfusion of hematoma region and perihematoma region. CTA source images was reviewed to make sure presence or absence of the spot sign. Results Finally, 53 patients(34 males, 19 females) were enrolled in our study according to exclusion criteria. Finally, 21 patients were classified into the normal group, 23 patients were classified into the mild group, and 9 patients were classified into the severe group. There were significant differences in hematoma size between the presence and absence of the perihematomal penumbra group(P<0.05). Thirteen(24.5%) patients presented with spot sign. Hematoma expansion occurred in 15(28.3%) patients on follow-up. In which 12 patients were with spot sign. Sensitivity, specificity, positive predictive value, and negative predictive value for expansion were 80.0%, 97.4%, 92.3%, and 92.5%, respectively. Conclusion In acute intracerebral hemorrhage patients, the perihematoma perfusion typing and CTA spot sign provide more radiological information that might assist in individualizing therapeutic decisions for patients by possibly forecasting perihematomal ischemia and hematoma enlargement.

Computed tomography perfusion study of hemodynamic changes and portal hyperperfusion in a rabbit model of small-for-size liver

BACKGROUND:Portal hyperperfusion in the small-for-size (SFS) liver can threaten survival of rabbits.Therefore,it is important to understand the hemodynamic changes in the SFS liver.METHODS:Twenty rabbits were divided into two groups:a control group and a modulation group.The control group underwent an extended hepatectomy.The modulation group underwent the same procedure plus splenectomy to reduce portal blood flow.CT perfusion examinations were performed on all rabbits before and after operation.Perfusion parameter values,especially portal vein perfusion (PVP),were analyzed.RESULTS:PVP in the modulation group was lower than in the control group after operation (P=0.002).In the control group,postoperative PVP increased by 193.7±55.1% compared with preoperative PVP.A weak correlation was found between the increased percentage of PVP and resected liver-to-body weight ratio (RLBWR) (r=0.465,P=0.033).In the modulation group,postoperative PVP increased by 101.4±32.5%.No correlation was found between the increased percentage of PVP and RLBWR (r=0.167,P=0.644).Correlations were found between PVP and serum alanine aminotransferase,aspartate aminotransferase,and total bilirubin after surgery (P<0.05).CONCLUSION:We successfully evaluated the characteristics of hemodynamic changes as well as the effects of splenectomy in the SFS liver in rabbits by the CT technique.

Computed tomography perfusion imaging as a potential imaging biomarker of colorectal cancer

Neovascularization was reported to arise early in the adenoma-carcinoma sequence in colorectal cancer(CRC),and the importance of angiogenesis in cancer progression has been established.Computed tomography(CT)perfusion(CTP)based on high temporal resolution CT images enables evaluation of hemodynamics of tissue in vivo by modeling tracer kinetics.CTP has been reported to characterize tumor angiogenesis,and to be a sensitive marker for predicting recurrence or survival in CRC.In this review,we will discuss the biomarker value of CTP in the management of CRC patients.

Computed tomography perfusion in liver and spleen for hepatitis B virus-related portal hypertension:A correlation study with hepatic venous pressure gradient

BACKGROUND Hepatic venous pressure gradient(HVPG)is the gold standard for diagnosis of portal hypertension(PH).However,its use can be limited because it is an invasive procedure.Therefore,it is necessary to explore a non-invasive method to assess PH.AIM To investigate the correlation of computed tomography(CT)perfusion of the liver with HVPG and Child-Pugh score in hepatitis B virus(HBV)-related PH.METHODS Twenty-eight patients(4 female,24 male)with gastroesophageal variceal bleeding induced by HBV-related PH were recruited in our study.All patients received CT perfusion of the liver before transjugular intrahepatic portosystemic stent-shunt(TIPS)therapy.Quantitative parameters of CT perfusion of the liver,including liver blood flow(LBF),liver blood volume(LBV),hepatic artery fraction,splenic blood flow and splenic blood volume were measured.HVPG was recorded during TIPS therapy.Correlation of liver perfusion with Child-Pugh score and HVPG were analyzed,and the receiver operating characteristic curve was analyzed.Based on HVPG(>12 mmHg vs≤12 mmHg),patients were divided into moderate and severe groups,and all parameters were compared.RESULTS Based on HVPG,18 patients were classified into the moderate group and 10 patients were classified into the severe group.The Child-Pugh score,HVPG,LBF and LBV were significantly higher in the moderate group compared to the severe group(all P<0.05).LBF and LBV were negatively associated with HVPG(r=-0.473,P<0.05 and r=-0.503,P<0.01,respectively),whereas splenic blood flow was positively associated with hepatic artery fraction(r=0.434,P<0.05).LBV was negatively correlated with Child-Pugh score.Child-Pugh score was not related to HVPG.Using a cutoff value of 17.85 mL/min/100 g for LBV,the sensitivity and specificity of HVPG≥12 mmHg for diagnosis were 80%and 89%,respectively.CONCLUSION LBV and LBF were negatively correlated with HVPG and Child-Pugh scores.CT perfusion imaging is a potential non-invasive quantitative predictor for PH in HBV-related liver cirrhosis.

Correlation of magnetic resonance signal characteristics and perfusion parameters assessed by volume perfusion computed tomography in hepatocellular carcinoma:Impact on lesion characterization

AIM: To find out if magnetic resonance(MR)-signal characteristics of hepatocellular carcinomas(HCC) correlate with perfusion parameters assessed by volume perfusion computed tomography(VPCT).METHODS: From October 2009 to January 2014, 26(mean age, 69.3 years) patients with 36 HCC lesions who underwent both VPCT and MR liver imaging were analysed. We compared signal intensity in the T1 wand T2w-images and wash-in/wash-out kinetics on postcontrast MR images with mean values of blood flow(BF, mL/100 mL per minute), blood volume(BV, mL/100 mL), k-trans(mL/100 mL per minute), arterial liver perfusion(mL/100 mL per minute), portal venous perfusion and hepatic perfusion index(HPI, %) obtained by VPCT. Signal intensity on magnetic resonance imaging(MRI) was classified hyper/iso/hypointense compared with surrounding liver parenchyma. RESULTS: Signal intensity on native T1w- and T2 wimages was hyper/iso/hypo in 4/16/16 and 21/14/1 lesions, respectively. Wash-in and wash-out contrast kinetics were found on MRI in 33 of 36 lesions(91.7%) and 25 of 36 lesions(69.4%), respectively. The latter was observed significantly more often in higher graded lesions(P < 0.005). HPI was 94.7% ± 6.5%. There was no significant relationship between lesion's MRsignal intensity, MR signal combinations, size and any of the VPCT-perfusion parameters. However HPI was constantly high in all HCC lesions.CONCLUSION: VPCT parameters add limited value to MR-lesion characterization. However in HCC lesions with atypical MR signal characteristics HPI can add a parameter to ensure HCC diagnosis.

Rest Thallium-201/Stress Technetium-99m Sestamibi Dual-Isotope Myocardial Perfusion Single-Photon Emission Computed Tomography in Detecting of Chronic Coronary Artery Disease

To investigate diagnostic accuracy of 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in chronic coronary artery disease. Sixty-seven patients with suspected CAD were enrolled in the prospective study. All patients underwent myocardial perfusion scintigraphy in SPECT with dual isotopes of T1-201 and dipyridamole stress Tc-99m sestamibi. Rest and stress imaging protocol were performed in 2 hours by dose of 3 mCi TI-201 and 25 mCi Tc-99m sestamibi. The acquisition parameters includes LEHR collimator, energy peak of 72 and 167 keV for T1-201 and 140 keV for Tc-99m, 180-degree rotation from RAO to LPO, matrix size 64x64, and 25second/frame/64 frames. The 20-segment model of left ventricle was used in automatic quantitation software. Coronary angiography was used as gold standard. CAD was defined as 50% of lumen stenosis on coronary angiography. Rest TI-201/stress tc-99m sestamibi dual-isotope SPECT demonstrated a sensitivity of 94.59% and specificity of 70%, positive predictive value of 79.54% and negative predictive value of 91.3% in detection of coronary artery disease. Sensitivity and specificity for detecting multi-vessel coronary artery disease were 82.75% and 81.57% for the left anterior descending, 77.77% and 91.83% for left circumflex and 94.11% and 82% for right coronary artery. 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT has high sensitivity, specificity, positive predictive value and negative predictive value in detecting chronic coronary artery disease with greater than 50% stenosis assessed by coronary angiography Moreover, this imaging protocol gives high imaging quality, time-saving and convenience.

Simultaneous fluorescence and Compton scattering computed tomography based on linear polarization X-ray

Purpose To propose a method for simultaneous fluorescence and Compton scattering computed tomography by using linearly polarized X-rays.Methods Monte Carlo simulations were adopted to demonstrate the feasibility of the proposed method.In the simulations,the phantom is a polytetrafluoroethylene cylinder inside which are cylindrical columns containing aluminum,water,and gold(Au)-loaded water solutions with Au concentrations ranging between 0.5 and 4.0 wt%,and a parallel-hole collimator imaging geometry was adopted.The light source was modeled based on a Thomson scattering X-ray source.The phantom images for both imaging modalities were reconstructed using a maximumlikelihood expectation maximization algorithm.Results Both the X-ray fluorescence computed tomography(XFCT)and Compton scattering computed tomography(CSCT)images of the phantom were accurately reconstructed.A similar attenuation contrast problem for the different cylindrical columns in the phantom can be resolved in the XFCT and CSCT images.The interplay between XFCT and CSCT was analyzed,and the contrast-to-noise ratio(CNR)of the reconstruction was improved by correcting for the mutual influence between the two imaging modalities.Compared with K-edge subtraction imaging,XFCT exhibits a CNR advantage for the phantom.Conclusion Simultaneous XFCT and CSCT can be realized by using linearly polarized X-rays.The synergy between the two imaging modalities would have an important application in cancer radiation therapy.

Assessment of tumor vascularization with functional computed tomography perfusion imaging in patients with cirrhotic liver disease

BACKGROUND:Hepatocellular carcinoma(HCC)is a common malignant tumor in China,and early diagnosis is critical for patient outcome.In patients with HCC,it is mostly based on liver cirrhosis,developing from benign regenerative nodules and dysplastic nodules to HCC lesions,and a better understanding of its vascular supply and the hemodynamic changes may lead to early tumor detection.Angiogenesis is essential for the growth of primary and metastatic tumors due to changes in vascular perfusion,blood volume and permeability.These hemodynamic and physiological properties can be measured serially using functional computed tomography perfusion(CTP)imaging and can be used to assess the growth of HCC.This study aimed to clarify the physiological characteristics of tumor angiogenesis in cirrhotic liver disease by this fast imaging method. METHODS:CTP was performed in 30 volunteers without liver disease(control subjects)and 49 patients with liver disease (experimental subjects:27 with HCC and 22 with cirrhosis). All subjects were also evaluated by physical examination, laboratory screening and Doppler ultrasonography of the liver. The diagnosis of HCC was made according to the EASL criteria. All patients underwent contrast-enhanced ultrasonography, pre-and post-contrast triple-phase CT and CTP study.A mathematical deconvolution model was applied to provide hepatic blood flow(HBF),hepatic blood volume(HBV), mean transit time(MTT),permeability of capillary vessel surface(PS),hepatic arterial index(HAI),hepatic arterial perfusion(HAP)and hepatic portal perfusion(HPP)data. The Mann-Whitney U test was used to determine differences in perfusion parameters between the background cirrhotic liver parenchyma and HCC and between the cirrhotic liver parenchyma with HCC and that without HCC.RESULTS:In normal liver,the HAP/HVP ratio was about 1/4. HCC had significantly higher HAP and HAI and lower HPP than background liver parenchyma adjacent to the HCC.The value of HBF at the tumor rim was significantly higher than that in the controls.HBF,HBV,HAI,HAP and HPP,but not MTT and PS,were significantly higher in the cirrhotic liver parenchyma involved with HCC than those of the controls. Perfusion parameters were not significantly different between the controls and the cirrhotic liver parenchyma not involved with HCC. CONCLUSIONS:CTP can clearly distinguish tumor from cirrhotic liver parenchyma and controls and can provide quantitative information about tumor-related angiogenesis, which can be used to assess tumor vascularization in cirrhotic liver disease.

Assessment of the hepatic microvascular changes in liver cirrhosis by perfusion computed tomography

AIM： TO assess the hepatic microvascular parameters in patients with liver cirrhosis by perfusion computed tomography （CT）. METHODS： Perfusion CT was performed in 29 patients without liver disease （control subjects） and 39 patients with liver cirrhosis, including 22 patients with compensated cirrhosis and 17 patients with decompensated cirrhosis, proved by clinical and laboratory parameters. CT cine-scans were obtained over 50 s beginning with the injection of 50 mL of contrast agent. Hepatic microvascular parameters, mean transit time （MTT） and permeability surface area product （PS） were obtained with the Perfusion 3 software （General Electric, ADW 4.2）. RESULTS： The overall differences of MTT and PS between control subjects, patients with compensated cirrhosis and those with decompensated cirrhosis were statistically significant （P = 0.010 and P = 0.002, respectively）. MTT values were 15.613 ± 4.1746 s, 12.592 ± 4.7518 s, and 11.721 ± 4.5681 s for the three groups, respectively, while PS were 18.945 ± 7.2347 mL/min per 100 mL, 22.767 ± 8.3936 mL/min per 100 mL, and 28.735 ± 13.0654 mL/min per 100 mL. MTT in decompensated cirrhotic patients were significantly decreased compared to controls （P = 0.017）, whereas PS values were remarkably increased （P = 0.001）.CONCLUSION： The hepatic microvascular changes in patients with liver cirrhosis can be quantitatively assessed by perfusion CT. Hepatic microvascular parameters （MTr and PS）, as measured by perfusion CT, were significantly altered in decompensated cirrhosis.

Computed tomography perfusion measurements for definition of lesions in early acute stroke

Background: Perfusion computed tomography (CT) is an evolving technique in the diagnosis of acute stroke. After complex deconvolution algorithms, perfusion color maps-cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT)— are produced, they give visual confirmation of perfusion deficit in ischemic area, but some discrepancies exist regarding this technique in reliability of quantitative detection of tissue viability: penumbra (tissue at risk) that surrounds core (necrosis). Purpose: The purpose of this prospective study was to define brain tissue viability grade on the basis of the perfusion CT parameters in acute stroke patients. Material and Methods: Multimodal CT imaging protocol (unenhanced CT of the brain, CT angiography of head and neck blood vessels, followed by brain perfusion CT and 24 hours follow-up brain CT) was performed. Perfusion deficit was detected first visually, with subsequent manual quantitative and relative measurements in affected and contra-lateral hemisphere in 87 patients. Results: Visual perfusion deficit on perfusion CT images was found in 78 cases (38 female, 40 male;mean age 30 - 84 years): penumbra lesion (n = 49) and core lesion (n = 42). Both lesion types were detected by increased MTT on perfusion CT map, penumbra area showed mean values 202.40% (113% - 345% ± 57.17) and core (41% - 320% ± 64.53) in comparison to contra-lateral hemisphere. CBV mean values in penumbra group were increased up to 113.10% (45% - 276% ± 36.29) and in core decreased till 41.82% (3% - 107% ± 27.09). CBF values were decreased up to 65.63% (31% - 137% ± 22) in penumbra lesion and markedly decreased till 25.94% (4% - 79% ± 17.35) in core. Conclusion: Our study shows that perfusion CT measurements relative threshold values are recommended in definition of penumbra and core lesions in acute stroke patients.

Low contrast medium and radiation dose for hepatic computed tomography perfusion of rabbit VX2 tumor

AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.

Perfusion characterization of liver metastases from endocrine tumors:Computed tomography perfusion

AIM:To assess prospectively parameters of computed tomography perfusion(CT p) for evaluation of vascularity of liver metastases from neuroendocrine tumors.METHODS:This study was approved by the hospital's institutional review board.All 18 patients provided informed consent.There were 30 liver metastases from neuroendocrine tumors.Patients were divided into three groups depending on the appearance of the liver metastases at the arterial phase of morphological CT(hyperdense,hypodense and necrotic).Sequential acquisition of the liver was performed before and for 2 min after intravenous injection of 0.5 mg/kg contrast medium,at 4 mL/s.Data were analyzed using deconvolution analysis to calculate blood flow(BF),blood volume(BV),mean transit time(MTT),hepatic arterial perfusion index(HAPI) and a bi-compartmental analysis was performed to obtain vascular permeability-surface area product(PS).Post-treatment analysis was performed by a radiologist and regions of interest were plotted on the metastases,normal liver,aorta and portal vein.RESULTS:At the arterial phase of the morphological CT scan,the aspects of liver metastases were hyperdense(n=21),hypodense(n=7),and necrotic(n=2).In cases of necrotic metastases,none of the CT p parameters were changed.Compared to normal liver,a significant difference in all CT p parameters was found in cases of hyperdense metastases,and only for HAPI and MTT in cases of hypodense metastases.No significant difference was found for MTT and HAPI between hypo-and hyperdense metastases.A significant decrease of PS,BV and BF was demonstrated in cases of patients with hypodense lesions PS(23±11.6 mL/100 g per minute) compared to patients with hyperdense lesions;PS(13.5±10.4 mL/100 g per minute),BF(93.7±75.4 vs 196.0±115.6mL/100 g per minute) and BV(9.7±5.9 vs 24.5 10.9 mL/100 g).CONCLUSION:CT p provides additional information compared to the morphological appearance of liver metastases.

A correlation of computed tomography perfusion and histopathology in tumor edges of hepatocellular carcinoma

BACKGROUND： The peripheral morphologic characteristics of hepatocellular carcinoma （HCC） reflect tumor growth patterns. Computed tomography （CT） perfusion is a new method to analyze hemodynamic changes in tissues. We assessed the relationship between CT perfusion and histopathologic findings in the periphery of HCC lesions. METHODS： Non-contrast CT, enhanced dual-phase CT, and CT perfusion were performed on 77 subjects （47 patients and 30 controls）. Based on the imaging findings of enhanced dual- phase CT, the tumor edges were classified into three types： type Ⅰ （sharp）; type Ⅱ （blurry）; and type Ⅲ （mixed）. The CT perfusion parameters included hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion. The tissue sections from resected specimens were subjected to routine hematoxylin and eosin staining and immunohistochemical staining for CD34. The correlations between microvessel density （MVD） and the CT perfusion parameters were analyzed using Pearson＇s product-moment correlation coefficient. Changes in the perfusion parameters in tumor edges of different tumor types were evaluated. RESULTS： Type Ⅰ （sharp）： the pathologic findings showed fibrous connective tissue capsules in the tumor edges, and an MVD 〈30/ram2. Type Ⅱ （blurry）： the histology showed that the edges were clear with no capsules and an MVD 〉30/ram2. Type Ⅲ （mixed）： the pathology was similar to that of types I and II, and an MVD 〉30/mm~. Hepatic blood flow, hepatic arterial fraction, hepatic arterial perfusion, and hepatic portal perfusion were significantly increased in the tumor edges of HCC patients compared to those of the controls （P〈0.05）. The correlation between CT perfusion parameters and MVD was higher in blurry tumor edges of type II than in those of types Ⅰ or Ⅲ. CONCLUSION： CT perfusion imaging of tumor edges may be helpful in revealing histopathological features, and indirectly reflect angiogenic changes of HCCs.

Features of Computed Tomography Perfusion of Mediastinal Lymphadenopathies:a Pathology-based Retrospective Study

Objective To explore the features of various mediastinal lymphadenopathies using computed tomography perfusion(CTP).Methods CTP parameters(CTPs) of the selected mediastinal nodes from 59 patients with pathology-proven malignant lymph nodes and of those from 29 patients with clinically diagnosed or pathology-proven inflammatory lymphadenopathies were collected.Patients were divided into subgroups by etiology and phase of primary disease,including different pathological malignant nodes and diverse inflammatory nodes.CTPs were defined as blood flow(BF),blood volume(BV),mean transit time(MTT),permeability(PMB),and time to peak(TTP).Differences of CTPs were compared between malignant and benign nodes,and among subgroups,respectively.Results In the mediastinum,no significant differences of CTPs were found between malignant and benign groups(all P>0.05),the same for subgroups of malignant nodes(all P>0.05).Acute lymphadenitis had higher BF and BV than chronic inflammatory,lymphoid tuberculosis,sarcoidosis and malignant nodes.The BF of malignant nodes was markedly slower than that of acute lymphadenitis(P=0.01),but faster than chronic inflammatory nodes(P=0.04) and sarcoidosis(P=0.03),with no significant difference compared with lymphoid tuberculosis.Pneumonia-complicated lymphoid tuberculosis showed the longest MTT while sarcoidosis displayed the shortest MTT,and inflammatory nodes,lymphoid tuberculosis without complicated pneumonia and malignant nodes had moderate MTT.Conclusion CTPs show promising potential in distinguishing various lymphadenopathies in the mediastinum,but more studies are needed to improve their specificity.

Computed tomography perfusion imaging evaluation of angiogenesis in patients with pancreatic adenocarcinoma

BACKGROUND Pancreatic adenocarcinoma is one of the most common malignant tumors of the digestive system.More than 80%of patients with pancreatic adenocarcinoma are not diagnosed until late stage and have distant or local metastases.AIM To investigate the value of computed tomography(CT)perfusion imaging in the evaluation of angiogenesis in pancreatic adenocarcinoma patients.METHODS This is a retrospective cohort study.Patients with pancreatic adenocarcinoma and volunteers without pancreatic diseases underwent CT perfusion imaging from December 2014 to August 2017 in Huashan Hospital,Fudan University Shanghai,China.RESULTS A total number of 35 pancreatic adenocarcinoma patients and 33 volunteers were enrolled.The relative blood flow(r BF),and relative blood volume(r BV)were significantly lower in patients with pancreatic adenocarcinoma than in the control group(P<0.05).Conversely,the relative permeability in patients with pancreatic adenocarcinoma was significantly higher than that in controls(P<0.05).In addition,r BF,r BV,and the vascular maturity index(VMI)were significantly lower in gradeⅢ-Ⅳpancreatic adenocarcinoma than in gradeⅠ-Ⅱpancreatic adenocarcinoma(P<0.05).Vascular endothelial growth factor(VEGF),CD105-MVD,CD34-MVD,and angiogenesis rate(AR)were significantly higher in gradeⅢ-Ⅳpancreatic adenocarcinoma than in gradeⅠ-Ⅱpancreatic adenocarcinoma(P<0.05).Significant correlations between r BF and VEGF,CD105-MVD,AR,and VMI(P<0.01)were observed.Moreover,the levels of r BV were statistically significantly correlated with those of VEGF,CD105-MVD,CD34-MVD,and VMI(P<0.01).CONCLUSION Perfusion CT imaging may be an appropriate approach for quantitative assessment of tumor angiogenesis in pancreatic adenocarcinoma.

Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample (I center dot 4.6 mm x 5.6 mm) was scanned using high-resolution X-ray computed tomography (HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 mu m. Combined with three-dimensional (3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.

Use of X-ray computed tomography to study structures and particle contacts of granite residual soil

A small problem about soil particle regularization and contacts but essential to geotechnical engineering was studied.The soils sourced from Guangzhou and Xiamen were sieved into five different particle scale ranges(d<0.075 mm,0.075 mm≤d<0.1 mm,0.1 mm≤d<0.2 mm,0.2 mm≤d<0.5 mm and 0.5 mm≤d<1.0 mm)to study the structures and particle contacts of granite residual soil.The X-ray micro computed tomography method was used to reconstruct the microstructure of granite residual soil.The particle was identified and regularized using principal component analysis(PCA).The particle contacts and geometrical characteristics in 3D space were analyzed and summarized using statistical analyses.The results demonstrate that the main types of contact among the particles are face-face,face-angle,face-edge,edge-edge,edge-angle and angle-angle contacts for particle sizes less than 0.2 mm.When the particle sizes are greater than 0.2 mm,the contacts are effectively summarized as face-face,face-angle,face-edge,edge-edge,edge-angle,angle-angle,sphere-sphere,sphere-face,sphere-edge and sphere-angle contacts.The differences in porosity among the original sample,reconstructed sample and regularized sample are closely related to the water-swelling and water-disintegrable characteristics of granite residual soil.