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.

Pulmonary lymphoma: computed tomography features with pathologic correlation

Objective: The aim of this study was to analyze the CT and pathology features of pulmonary lymphoma and to improve the understanding of this disease. Methods: The CT findings of 23 cases with pulmonary lymphoma were retrospectively analyzed and correlated with histopathology. Results: Of the 23 cases with pulmonary lymphoma, there were Hodgkin lymphoma (5 cases) and non-Hodgkin lymphoma (18 cases). Multiple lesions were assessed in 16 cases and single lesion in 7 cases. The imaging findings were classified into 3 types: lobar and segmental involvement type (9/23 cases, 39.13%), nodular or mass-like involvement type (8/23 cases, 34.78%) and mixed type (6/23 cases, 26.09%). Air bronchogram sign (14/23 cases, 60.8%), CT angiogram sign (12/23 cases, 52.17%), ground glass opacity nodules (3/23 cases, 13.04%) and lesion across pulmonary lobes (4/23,17.39%) were the characteristic features of pulmonary lymphoma. Conclusion: Relative characteristic CT features of pulmonary lymphoma could be revealed, which shows clinical significance in the diagnosis of the disease.

Reproducibility of perfusion CT derived CBV and rCBV measurements with different slice thickness in patients with brain neoplasms

Objective:To assess inter-and intraobserver reproducibility for measuring perfusion CT derived cerebral blood volume (CBV) and relative cerebral blood volume (rCBV) with different slice thickness in patients with brain neoplasms. Meth- ods: Three independent observers who were blinded to the histopathologic diagnosis performed perfusion derived CBV and rCBV measurements with 5 mm and 10 mm slice thickness in 52 patients with various cerebral neoplasms. The results of the measurements with different slice thickness were compared. Calculation of coefficient of variation (CV), and relative paired difference of the measurements were used to determine the levels of inter- and intraobserver reproducibility. Results: The differences of CBV and rCBV measurements between different slice thickness groups were statistically significant (P < 0.05) respectively in observer 2, and were not significant in the other two observers (P > 0.05). For the same slice thickness, both the difference of CBV and rCBV measurements among the three observers were not statistically significant. Interobserver CV and relative paired difference of the measurements with 10 mm slice thickness group were slightly lower than those of 5 mm slice thickness group. Interobserver CV and relative paired difference of CBV group were slightly lower than those of rCBV group. The intraobserver differences of CBV and rCBV in 10 mm slice thickness group were statistically significant for observer 2 respectively. No other intraobserver differences of measurements were statistically significant. CV and relative paired difference of intraobserver CBV and rCBV measurements for observer 2 were significantly higher than for the other two observers. Conclusion: High reproducibility of CBV and rCBV measurements was acquired with the two different slice thickness. Suitable training may be helpful to maintain a high level of consistency for measurements.

Preliminary Application of Perfusion Imaging in Neoplasm in the Brain and Body with Multi-slice Helical CT

Objective： To evaluate the clinical value of perfusion imaging in neoplasm in the brain and body with Multi-slice helical CT. Methods： Twenty-eight patients with neoplasm were subjected to perfusion imaging with multi-slice helical CT, including 22 patients with brain neoplasm and 6 patients with body neoplasm. At first, CT routine scan was preformed to localize central slices of neoplasm. Then perfusion imaging of 4 and identical slices in central slices of neoplasm was performed by using CT cine scan. Scanning images were transferred into ADW3.1 work-station to create and analyze perfusion images and parameters. Results： Perfusion parameters of cerebral neoplasm had a remarkable increase. But, CBF value of different cerebral neoplasms had partial overlap; CBV value was increased slightly; MTT value had no apparently clinical value; PS value was increased significantly, pituitary neoplasm〉meningoma〉cerebral glioma≈cerebral metastasis. PS value could reveal the characters of cerebral neoplasm and had apparently clinical value. Perfusion parameters of body neoplasms have a remarkable increase too. Body tumors were liable to be interfered by breath movement. Perfusion parameters were helpful to differentiation diagnosis of neoplasm in the brain and body. PS images of neoplasm in the brain and body were helpful to defining tumor outline and finding small tumor. Conclusion： MSCT perfusion imaging provided a precise and relative simple method to quantitatively estimate blood perfusion status in tumors in the brain and body. The technique can be easily implemented on clinical scanners.

Contrast-enhanced ultrasound and contrast-enhanced computed tomography for differentiating mass-forming pancreatitis from pancreatic ductal adenocarcinoma:a meta-analysis

Background:Patients with mass-forming pancreatitis(MFP)or pancreatic ductal adenocarcinoma(PDAC)presented similar clinical symptoms,but required different treatment approaches and had different survival outcomes.This meta-analysis aimed to compare the diagnostic performance of contrast-enhanced ultrasound(CEUS)and contrast-enhanced computed tomography(CECT)in differentiating MFP from PDAC.Methods:A literature search was performed in the PubMed,EMBASE(Ovid),Cochrane Library(CENTRAL),China National Knowledge Infrastructure(CNKI),Weipu(VIP),and WanFang databases to identify original studies published from inception to August 20,2021.Studies reporting the diagnostic performances of CEUS and CECT for differentiating MFP from PDAC were included.The meta-analysis was performed with Stata 15.0 software.The outcomes included the pooled sensitivity,specificity,positive likelihood ratio(+LR),negative likelihood ratio(-LR),diagnostic odds ratio(DOR),and summary receiver operating characteristic(SROC)curves of CEUS and CECT.Meta-regression was conducted to investigate heterogeneity.Bayesian network meta-analysis was conducted to indirectly compare the overall diagnostic performance.Results:Twenty-six studies with 2115 pancreatic masses were included.The pooled sensitivity and specificity of CEUS for MFP were 82%(95%confidence interval[CI],73%-88%;I^(2)=0.00%)and 95%(95%CI,90%-97%;I^(2)=63.44%),respectively;the overall+LR,-LR,and DOR values were 15.12(95%CI,7.61-30.01),0.19(95%CI,0.13-0.29),and 78.91(95%CI,30.94-201.27),respectively;and the area under the SROC curve(AUC)was 0.90(95%CI,0.87-92).However,the overall sensitivity and specificity of CECT were 81%(95%CI,75-85%;I^(2)=66.37%)and 94%(95%CI,90-96%;I^(2)=74.87%);the overall+LR,-LR,and DOR values were 12.91(95%CI,7.86-21.20),0.21(95%CI,0.16-0.27),and 62.53(95%CI,34.45-113.51),respectively;and,the SROC AUC was 0.92(95%CI,0.90-0.94).The overall diagnostic accuracy of CEUS was comparable to that of CECT for the differential diagnosis of MFP and PDAC(relative DOR 1.26,95%CI[0.42-3.83],P>0.05).Conclusions:CEUS and CECT have comparable diagnostic performance for differentiating MFP from PDAC,and should be considered as mutually complementary diagnostic tools for suspected focal pancreatic lesions.

Clinical study of stomach neoplasm CT perfusion imaging

Objection:The purpose of this study is preliminarily to discuss stomach perfusion imaging technique with Multi-slice CT and its clinical application value in stomach neoplasm.Methods:Fifteen patients with known stomach neoplasm performed perfusion imaging with 4 or 16 slice CT.Performing perfusion imaging in central slice of neoplasm,using CT cine scan,slice thick 10 mm/2i;with high pressure syringe,injecting quickly from right elbow-front vein,dosage 45-50 mL,injec-tion rate 3.5-4.0 mL/s,scanning delay time 5 s,scanning total time 45 s.We performed perfusion CT post-processing using pancreatic mode of perfusion CT software.Blood flow(BF),blood volume(BV),mean transit time(MTT),and permeability surface(PS) of gastric wall and tumor were computed for every case.Results:BF,BV,MTT and PS of gastric tumor were 116.68 ± 90.09 mL/(min·100 g),9.57 ± 8.12 mL/100 g,10.07 ± 7.74 s,20.78 ± 19.68 mL/(min·100g),respectively.The P values for each CT perfusion parameters between gastric tumor and normal gastric wall were 0.001,0.021,0.155 and 0.031,respectively.Conclusion:Perfusion CT can provide hemodynamics of gastric tumors and play a key role in the diagnosis of gastric tumors.It's clinical application prospect will be fully broad.

Evaluation of the dual vascular supply patterns in ground-glass nodules with a dynamic volume computed tomography

BACKGROUND In recent years,the detection rate of ground-glass nodules(GGNs)has been improved dramatically due to the popularization of low-dose computed tomography(CT)screening with high-resolution CT technique.This presents challenges for the characterization and management of the GGNs,which depends on a thorough investigation and sufficient diagnostic knowledge of the GGNs.In most diagnostic studies of the GGNs,morphological manifestations are used to differentiate benignancy and malignancy.In contrast,few studies are dedicated to the assessment of the hemodynamics,i.e.,perfusion parameters of the GGNs.AIM To assess the dual vascular supply patterns of GGNs on different histopathology and opacities.METHODS Forty-seven GGNs from 47 patients were prospectively included and underwent the dynamic volume CT.Histopathologic diagnoses were obtained within two weeks after the CT examination.Blood flow from the bronchial artery[bronchial flow(BF)]and pulmonary artery[pulmonary flow(PF)]as well as the perfusion index(PI)=[PF/(PF+BF)]were obtained using first-pass dual-input CT perfusion analysis and compared respectively between different histopathology and lesion types(pure or mixed GGNs)and correlated with the attenuation values of the lesions using one-way ANOVA,student’s t test and Pearson correlation analysis.RESULTS Of the 47 GGNs(mean diameter,8.17 mm;range,5.3-12.7 mm),30(64%)were carcinoma,6(13%)were atypical adenomatous hyperplasia and 11(23%)were organizing pneumonia.All perfusion parameters(BF,PF and PI)demonstrated no significant difference among the three conditions(all P>0.05).The PFs were higher than the BFs in all the three conditions(all P<0.001).Of the 30 GGN carcinomas,14 showed mixed GGNs and 16 pure GGNs with a higher PI in the latter(P<0.01).Of the 17 benign GGNs,4 showed mixed GGNs and 13 pure GGNs with no significant difference of the PI between the GGN types(P=0.21).A negative correlation(r=-0.76,P<0.001)was demonstrated between the CT attenuation values and the PIs in the 30 GGN carcinomas.CONCLUSION The GGNs are perfused dominantly by the PF regardless of its histopathology while the weight of the BF in the GGN carcinomas increases gradually during the progress of its opacification.

Progression of hepatic hyperperfusion disorders revealed during follow-up CT scan of digestive system neoplasm

Objective： The aim of this study was to investigate progression of hepatic hyperperfusion disorders revealed during follow-up contrast material-enhanced multi-slice spiral computed tomography （MSCT） scan of digestive system neoplasm. Methods： Three-phase contrast material-enhanced MSCT were performed during the follow-up in patients with digestive system malignant tumor confirmed histologically. The progression of hepatic hyperperfusion disorders revealed on contrast material-enhanced CT image were investigated at the 2 years follow-up with approximately 6 months interval. Results： The hepatic hyperperfusion disorders were showed in 39 patients on follow-up contrast material-enhanced MSCT scans. Among the 39 patients, initial hyperperfusion disorders were revealed in 6 （15.38%）, 26 （66.67%）, and 7 （17.95%） patients in 6, 12, and 18 months during follow-up respectively. The initial hyperperfusion disorders revealed in 12 months were more frequent than those revealed in 6 months （X2 = 14.82, P 〈 0.05） and 18 months （X2 = 15.02, P 〈 0.05）. Among the 39 patients, the hyperperfusion disorders progressed into liver metastasis based on typical CT findings in 37 （94.87%） patients, and were not obvious changes in 2 （5.13%） patients. Among the 37 patients, the hyperperfusion disorders progressed into metastasis in 10 （25.64%） patients in 6 months after the hyperperfusion disorders were revealed, and in 27（69.23%） patients in 12 months. The hyperperfusion disorders developing into metastasis were more in 12 months than those in 6 months （X2= 14.98, P 〈 0.05）. Conclusion： Most hepatic hyperperfusion disorders revealed at the follow-up of digestive system neoplasm may be early manifestations of liver metastasis. The careful follow-up of hepatic hyperperfusion disorders is necessary.

Utility of CT in differentiating liver metastases of well-differentiated gastroenteropancreatic neuroendocrine neoplasms from poorly-differentiated neuroendocrine neoplasms

Objective： To determine the capability of dynamic enhanced computed tomography（CT） to differentiate liver metastases（LMs） of well-differentiated from poorly-differentiated gastroenteropancreatic neuroendocrine neoplasms（GEP-NENs）.Methods： Patients with LMs of GEP-NENs who underwent dynamic enhanced CT examination in Peking University Cancer Hospital from January 2009 to October 2015 were included and data were retrospectively analyzed. We assessed the qualitative and quantitative CT features to identify the significant differentiating CT features of LMs of poorly-differentiated GEP-NENs from those of well-differentiated GEP-NENs using univariate analysis and a multivariate logistic regression model.Results： The study included 22 patients with LMs of well-differentiated GEP-NENs and 32 patients with LMs of poorly-differentiated GEP-NENs. Univariate analysis revealed statistically significant differences between the LMs of well-and poorly-differentiated GEP-NENs in terms of feeding arteries（36.4% vs. 75.0%, χ2=8.061,P=0.005）, intratumoral neovascularity（18.2% vs. 59.4%, χ2=9.047, P=0.003）, lymphadenopathy（27.3% vs. 81.2%,χ2=15.733, P〈0.001）, tumor-to-aortic ratio in the hepatic arterial and portal venous phase（T-A/AP： 0.297±0.080 vs.0.251±0.059, t=2.437, P=0.018; T-A/PVP： 0.639±0.138 vs. 0.529±0.117, t=3.163, P=0.003） and tumor-to-liver ratio in the hepatic arterial phase（T-L/AP： 1.108±0.267 vs. 0.907±0.240, t=2.882, P=0.006）. The LMs of poorlydifferentiated GEP-NENs showed more feeding arteries, more intratumoral neovascularity, more lymphadenopathy and a lower tumor-to-aortic ratio. Multivariate analysis suggested that intratumoral neovascularity [P=0.015, OR=0.108, 95% confidence interval（95% CI）, 0.018–0.646], lymphadenopathy（P=0.001,OR=0.055, 95% CI, 0.009–0.323） and T-A/PVP（P=0.004, OR=5.3 E–5, 95% CI, 0.000–0.044） were independent factors for differentiating LMs of poorly-differentiated from well-differentiated GEP-NENs.Conclusions： Dynamic enhanced CT features（intratumoral neovascularity, lymphadenopathy and T-A/PVP）are useful in the pathological classification of LMs of GEP-NENs.

Clinical application of hepatic CT perfusion

Complicated changes occur in hemodynamics of hepatic artery and vein, and portal vein under various kinds of pathologic status hepatic blood supply. This because of distinct double article reviews the clinical application of hepatic computed tomography perfusion in some liver diseases.

Detection and differentiation of early hepatocellular carcinoma from cirrhosis using CT perfusion in a rat liver model

BACKGROUND： Functional imaging such as CT perfusion can detect morphological and hemodynamic changes in he- patocellular carcinoma （HCC）. Pre-carcinoma and early HCC nodules are difficult to differentiate by observing only their hemodynamics changes. The present study aimed to investi- gate hemodynamic parameters and evaluate their differential diagnostic cut-off between pre-carcinoma and early HCC nodules using CT perfusion and receiver operating characteristic （ROC） curves. METHODS： Male Wistar rats were randomly divided into control （n=20） and experimental （n=70） groups. Diethylnitrosamine （DEN） was used to induce pre-carcinoma and early HCC nodules in the experimental group. Perfusion scanning was carried out on all survival rats discontinuously from 8 to 16 weeks. Hepatic portal perfusion （HPP）, hepatic arterial fraction （HAF）, hepatic arterial perfusion （HAP）, hepatic blood volume （HBV）, hepatic blood flow （HBF）, mean transit time （MTT） and permeability of capillary vessel surface （PS） data were provided by mathematical deconvolution model. The perfusion parameters were compared among the three groups of rats （control, pre-carcinoma and early HCC groups） using the Kruskal-Wallis test and analyzed with ROC curves. Histological examination of the liver tissues with hematoxylin and eosin staining was performed after CT scan.RESULTS： For HPP, HAF, HBV, HBF and MTT, there were significant differences among the three groups （P〈0.05）. HAF had the highest areas under the ROC curves： 0.80 （control vs pre-carcinoma groups） and 0.95 （control vs early HCC groups） with corresponding optimal cut-offs of 0.37 and 0.42, respectively. The areas under the ROC curves for HPP was 0.79 （control vs pre-carcinoma groups） and 0.92 （control vs early HCC groups） with corresponding optimal cut-offs of 136.60 mL/min/100 mg and 108.47 mL/min/100 mg, respectively. CONCLUSIONS： CT perfusion combined with ROC curve analysis is a new diagnosis model for distinguishing between pre-carcinoma and early HCC nodules. HAF and HPP are the ideal reference indices.

Perfusion CT findings in liver of patients with tumor during chemotherapy

AIM: To investigate the microcirculation changes in liver of patients with tumor during chemotherapy by perfusion computed tomography (CT). METHODS: Sixty patients with tumor and 20 controls were enrolled in this study. Perfusion CT parameters of patients and controls were compared, including hepatic perfusion index (HPI), mean transit time (MTT), and permeability-surface area product (PS). Correlation between perfusion CT parameters, treatment cycle and alanine aminotransferase (ALT) level was studied. RESULTS: No difference was found in HPI (25.68% ± 7.38% vs 26.82% ± 5.13%), MTT (19.67 ± 5.68 s vs21.70 ± 5.43 s) and PS (17.00 ± 4.56 mL/100 mL per min vs 19.92 ± 6.35 mL/100 mL per min) between pa- tients and controls. The HPI and MTT were significantly higher in patients undergoing 2 cycles of chemotherapy than in controls and those undergoing 1 cycle of che- motherapy (29.76% ± 5.87% vs 25.68% ± 7.38% and 25.35% ± 4.05%, and 25.61 ± 5.01 s vs 19.67 ± 5.68 s and 19.74 ± 4.54 s, respectively, P < 0.05). The HPI was higher in patients with hepatic steatosis than in controls and those without hepatic steatosis (30.85% ± 6.17% vs 25.68% ± 7.38% and 25.70% ± 4.24%, P < 0.05). Treatment cycle was well correlated with HPI and MTT (r = 0.40, r = 0.50, P < 0.01). ALT level was not correlated with perfusion CT parameters. CONCLUSION: HPI and MTT are significantly increased in patients with tumor during chemotherapy and well correlated with treatment cycle. Chemotherapy affects hepatic microcirculation in patients with tumor. Changes in hepatic microcirculation can be quantitatively assessed by perfusion CT.

Application of CT perfusion imaging in detection of tumor angiogenesis in osteosarcoma

Objective： The aim of the study was to explore the application of 64-slice spiral computed tomography perfusion imaging （CTPI） in evaluating angiogenesis in human osteosarcoma. Methods： Twenty-six patients （18 males and 8 females ranging from 9 to 56 years old, with an average of 19 years） with osteosarcoma underwent 64-slice spiral CTPI. We analyzed the correlations of CTPI parameters including blood flow （BF）, blood volume （BV）, time to peak （TTP）, and permeability surface （PS） with the expression of markers of angiogenesis. Statistical analysis was performed with paired-samples t test, and Pearson correlation analysis was employed to investigate the correlations of CTPI parameters with microvessel density （MVD）. Results： Mean BF, BV, TTP, and PS values of osteosarcoma group were （46.6 ± 25.1） mL/100 g/min, （61.8 ± 29.5） mL/100 g, （122.9 ± 26.2） seconds, and （44.5 ± 14.6） mL/100 g/min, respectively. Those in the normal muscle group were （5.2 ± 6.6） mL/100 g/min, （9.6 ± 7.3） mL/100 g, （115.5 ± 33.1） seconds and （17.0 ± 29.3） mL/100 g/min, respectively. Osteosarcoma group showed higher BF, BV and PS compared with the normal muscle group （P = 0.000, P = 0.000, and P = 0.000, respectively）. However, no significant difference was found in TTP between osteosarcoma tissue and normal adjacent muscle tissue （P = 0.273）. BF, BV, and PS were positively correlated with MVD （r = 0.83, P = 0.000; r = 0.87, P = 0.000; and r = 0.63, P = 0.001, respectively）. No correlation was found between TTP and MVD （r = –0.02, P = 0.93）. Conclusion： CTPI is useful for assessing tumor vascularity of osteosarcoma and CTPI parameters are positively correlated with MVD.

CT Perfusion Imaging Predicts One-Month Outcome in Patients with Acute Spontaneous Hypertensive Intracerebral Hemorrhage

Purpose: Little is known about the relationship between perihematomal perfusion parameters in acute spontaneous hypertensive intracerebral hemorrhage patients and recent outcome. The purpose of this study was to evaluate the relationship between the perfusion parameters of the perihematomal brain tissue and the recent prognosis of patients with acute spontaneous hypertensive intracerebral hemorrhage (shICH) using CT perfusion (CTP) imaging. Methods: Twenty-six patients with clinical and CT diagnosed supratentorial shICH received CTP scanning within 8 - 19 h after symptom onset. At the maximum levels of the hematoma, cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of perihematomal area (isodense within 1cm rim of perilesion area on plain CT) and contralateral mirrored hemisphere were measured, and rCBF, rCBV, rMTT were calculated (ipsilateral/contralateral). The one-month follow-up in accordance with daily living table (Barthel index, BI) by telephone was recorded. Results: The CBV, CBF, and MTT values of perihematoma area were (1.61 ± 1.53) ml·100 g-1, (16.48 ± 12.58) ml·100 g-1·min-1, and (9.12 ± 2.57) s, respectively. (For more information,please refer to the PDF)

Experimental study on angiogenesis in rabbit VX_2 brain tumor using perfusion CT

Objective： To study the perfusion CT features of rabbit VX2 brain tumor with correlation to MVD and VEGF, and to validate perfusion CT for reflection of tumor angiogenesis. Methods： Rabbit VX2 brain tumor model was established by injection of 100 μL viable tumor cells （10qmL） through a 2 mm-hole 5 mm to the right of the sagittal suture and 5 mm posterior to the coronal suture bored by dental drill. MRI was performed every 2 days after seven days of implantation to evaluate the growth of the tumor. Twenty New Zealand White rabbits with tumor size over 3 mm in diameter were randomly divided into 2 groups according to the tumor growth time with those less than 3 weeks as group 1 and those more than 3 weeks as group 2, and perfusion CT were performed accordingly. CT measurements of BV, BF and PS from tumor, peritumor and contralateral normal tissue regions were obtained. After that the animals were sacrificed and 2% Evans blue （2 mL/kg） was given intravenously in 16 of these animals 1 h prior to sacrifice to detect breakdown of the blood brain barrier. VEGF and MVD were evaluated in immunohistochemical examination of the specimens. Results： Tumor had significantly higher BV, BF and PS （P=0.000） than peritumor and normal tissue region. Tumor BV, BF and MVD in group 2 were significantly higher than that in group 1 （P〈0.01）. Significant linear correlation was found between MVD and BV （t=-0.915, P=-0.000）, MVD and BF （t=0.901, P=-0.000）, and MVD and PS （t=-0.459, P=0.042）. We also found a rank correlation between PS and blue stain of tumor （rs=0.861, P=0.000）. Conclusion： Perfusion CT can distinguish tumor from peritumor and normal tissue clearly, reflect tumor angiogenesis accurately, and provide useful information for the evaluation of brain tumor.

Subtraction Perfusion CT: A Technical Note

It is challenging to attempt to obtain CT perfusion (CTP) images of the hyperdense tissues, which could conceal the density of contrast material during perfusion study. We report a new technique of subtraction CTP (SCTP) to compensate the shortcomings. SCTP post-processed by perfusion software for the data of post-perfusion images subtracting pre-perfusion corresponding images slice by slice in CTP source images is technically feasible without any adverse effects on patients. It provides a new functional imaging with quantitatively hemodynamic indexes of tissue microcirculation and reflects accurately the change of blood flow in tissues and organs.

Artificial intelligence models based on non-contrast chest CT for measuring bone mineral density

Objective To observe the value of artificial intelligence(AI)models based on non-contrast chest CT for measuring bone mineral density(BMD).Methods Totally 380 subjects who underwent both non-contrast chest CT and quantitative CT(QCT)BMD examination were retrospectively enrolled and divided into training set(n=304)and test set(n=76)at a ratio of 8∶2.The mean BMD of L1—L3 vertebrae were measured based on QCT.Spongy bones of T5—T10 vertebrae were segmented as ROI,radiomics(Rad)features were extracted,and machine learning(ML),Rad and deep learning(DL)models were constructed for classification of osteoporosis(OP)and evaluating BMD,respectively.Receiver operating characteristic curves were drawn,and area under the curves(AUC)were calculated to evaluate the efficacy of each model for classification of OP.Bland-Altman analysis and Pearson correlation analysis were performed to explore the consistency and correlation of each model with QCT for measuring BMD.Results Among ML and Rad models,ML Bagging-OP and Rad Bagging-OP had the best performances for classification of OP.In test set,AUC of ML Bagging-OP,Rad Bagging-OP and DL OP for classification of OP was 0.943,0.944 and 0.947,respectively,with no significant difference(all P>0.05).BMD obtained with all the above models had good consistency with those measured with QCT(most of the differences were within the range of Ax-G±1.96 s),which were highly positively correlated(r=0.910—0.974,all P<0.001).Conclusion AI models based on non-contrast chest CT had high efficacy for classification of OP,and good consistency of BMD measurements were found between AI models and QCT.

Validation of quantitative computed tomography-derived areal bone mineral density with dual energy X-ray absorptiometry in an elderly Chinese population

Background The performance of computed tomography X-ray absorptiometry （CTXA） against the dual energy X-ray absorptiometry （DXA） as standard has not been studied in Chinese population. The aim of this study was to evaluate the precision of this measurement and validate the value of quantitative computed tomography （QCT） by comparing CTXA results with DXA results in an elderly Chinese population. Methods One hundred and three females of 46 to 76 years old and 49 males of 52 to 76 years old were recruited from the Prospective Urban Rural Epidemiology study. All subjects underwent hip scans by both QCT and DXA on the same day. For precision determination, 30 subjects had duplicate DXA hip scans. The hip QCT data of a subset of 27 subjects were separately analyzed by two observers and reanalyzed by one observer at a different time. The inter- and intra-observer variations of CTXA measurement were assessed, and the difference and correlation between CTXA and DXA results were analyzed. Results The inter- and intra-observer variations of CTXA were 0.070 and 0.024 g/cm^2 in the femoral neck （FN）, and 0.030 and 0.012 g/cm2 in the total hip （TH）, which were comparable to the DXA inter-scan variations （0.013 g/cm2 for FN and 0.014 g/cm2 for TH）. The results of CTXA bone mineral density （BMD） were highly correlated with those of DXA （R2 = 0.810 for FN and R2 = 0.878 for TH）. The BMD values of CTXA in FN and TH were lower than those of DXA by 21.0% and 17.8% （P〈0.05）, respectively. However, after appropriate transformation, the difference was eliminated and a comparable T score could be obtained. Conclusions CTXA shows good agreement with DXA for the measurement of BMD in the proximal femur, which makes QCT suitable for the quantification of bone mineral content in the hip and helpful for the diagnosis of osteoporosis.

Bone diseases in rabbits with hyperparathyroidism: computed tomography, magnetic resonance imaging and histopathology

Background Hyperparathyroidism （HPT） occurs at an early age and has a high disability rate. Unfortunately, confirmed diagnosis in most patients is done at a very late stage, when the patients have shown typical symptoms and signs, and when treatment does not produce any desirable effect. It has become urgent to find a method that would detect early bone diseases in HPT to obtain time for the ideal treatment. This study evaluated the accuracy of high field magnetic resonance imaging （MRI） combined with spiral computed tomography （SCT） scan in detecting early bone diseases in HPT, through imaging techniques and histopathological examinations on an animal model of HPT. Methods Eighty adult rabbits were randomly divided into two groups with forty in each. The control group was fed normal diet （Ca：P = 1：0.7）; the experimental group was fed high phosphate diet （Ca：P = 1：7） for 3, 4, 5, or 6-month intervals to establish the animal model of HPT. The staging and imaging findings of the early bone diseases in HPT were determined by high field MRI and SCT scan at the 3rd, 4th, 5th and 6th month. Each rabbit was sacrificed after high field MRI and SCT scan, and the parathyroid and bones were removed for pathological examination to evaluate the accuracy of imaging diagnosis. Results Parathyroid histopathological studies revealed hyperplasia, osteoporosis and early cortical bone resorption. The bone diseases in HPT displayed different levels of low signal intensity on T1WI and low to intermediate signal intensity on T2WI in bone of stage 0, Ⅰ, Ⅱ or Ⅲ, but showed correspondingly absent, probable, osteoporotic and subperiosteal cortical resorption on SCT scan. Conclusion High field MRI combined with SCT scan not only detects early bone diseases in HPT, but also indicates staging, and might be a reliable method of studying early bone diseases in HPT.

Imaging of bone metastasis: An update

Early detection of skeletal metastasis is critical for accurate staging and optimal treatment. This paper briefly reviews our current understanding of the biological mechanisms through which tumours metastasise to bone and describes the available imaging methods to diagnose bone metastasis and monitor response to treatment. Among the various imaging modalities currently available for imaging skeletal metastasis, hybrid techniques whichfuse morphological and functional data are the most sensitive and specific, and positron emission tomography(PET)/computed tomography and PET/magnetic resonance imaging will almost certainly continue to evolve and become increasingly important in this regard.