ABSTRACT
Objective To study the features and clinical value of 18F-fluorodeoxyglucose (FDG) PET/CT in prosthetic vascular graft infections (PVGIs) after endovascular aortic repair (EVAR).Methods Data of 27 patients (22 males and 5 females,age range:21-77 years,average age:42 years) who underwent PET/CT imaging after EVAR from October 2011 to January 2017 were studied retrospectively.A total of 11 cases were finally diagnosed as PVGIs (PVGIs group),and the remaining 16 cases were defined as the negative group.PET/CT imaging features were compared between two groups.The detection rates of PET/CT and aortic CT angiography (CTA) for PVGIs were calculated and compared.Two-sample t test and Fisher exact test were used for data analysis.Results Significant uptake of FDG around the stents was detected by PET/CT in all patients in PVGIs group.The maximum standardized uptake value (SUVmax) of 11 patients in early imaging was 14.9±3.3 (10.8-21.8) and that of 9 patients in delayed imaging was 13.8±3.4 (10.6-19.1).Six patients of the negative group underwent the delayed imaging.No uptake or mild uptake of FDG around the stents was observed in negative group,with the SUVmax of 1.7±0.8(1.0--2.9) in early imaging and 1.6±0.7(1.1-2.5) in delayed imaging.SUVmax in negative group was significantly lower than that in PVGIs group (t values:12.6 and 11.8,both P＜0.001).Five patients in PVGIs group were diagnosed as graft infections by the aortic CTA,while the remaining 6 cases showed no definitive infection signs on aortic CTA.The detection rate of aortic CTA was 5/11,which was significantly lower than that of PET/CT (P＜0.05).In negative group,6 patients had abnormal FDG uptakes in other areas and were finally confirmed as infectious lesions (n=3) or malignant tumors (n=3).Conclusion Compared with aortic CTA,18F-FDG PET/CT is more sensitive and accurate in detection and diagnosis of PVGIs after EVAR.
ABSTRACT
Autoimmune pancreatitis (AIP) is a unique subtype of chronic pancreatitis, which shares many clinical presentations with pancreatic ductal adenocarcinoma (PDA). The misdiagnosis of AIP often leads to unnecessary pancreatic resection. F-FDG positron emission tomography/ computed tomography (PET/CT) could provide comprehensive information on the morphology, density, and functional metabolism of the pancreas at the same time. It has been proved to be a promising modality for noninvasive differentiation between AIP and PDA. However, there is a lack of clinical analysis of PET/CT image texture features. Difficulty still remains in differentiating AIP and PDA based on commonly used diagnostic methods. Therefore, this paper studied the differentiation of AIP and PDA based on multi-modality texture features. We utilized multiple feature extraction algorithms to extract the texture features from CT and PET images at first. Then, the Fisher criterion and sequence forward floating selection algorithm (SFFS) combined with support vector machine (SVM) was employed to select the optimal multi-modality feature subset. Finally, the SVM classifier was used to differentiate AIP from PDA. The results prove that texture analysis of lesions helps to achieve accurate differentiation of AIP and PDA.
Subject(s)
Humans , Adenocarcinoma , Diagnostic Imaging , Algorithms , Autoimmune Diseases , Diagnostic Imaging , Diagnosis, Differential , Fluorodeoxyglucose F18 , Pancreatic Neoplasms , Diagnostic Imaging , Pancreatitis , Diagnostic Imaging , Positron Emission Tomography Computed Tomography , Support Vector MachineABSTRACT
Objective To investigate the clinical value of Fluorine-18-fluorodeoxyglucose (18 F-FDG)positron-emission temography/computed tomography (PET/CT) examination to predict microvascular invasion (MVI) of hepatocellular carcinoma (HCC).Methods The retrospective cohort study was conducted.The clinicopathological data of 51 HCC patients who were admitted to Changhai Hospital of the Second Military Medical University (32 patients) and Universal Medical Imaging Diagnostic Center (19 patients) from January 2013 to October 2017 were collected.Of 51 patients receiving postoperative pathological examination,21 diagnosed with positive MVI and 30 diagnosed with negative MVI were respectively allocated into the positive and negative MVI groups.All the patients received preoperative 1s F-FDG PET/CT examination and underwent surgery after related examinations.Two imaging doctors independently read films and made a semi-quantitative analysis.Observation indicators:(1) results of 18F-FDG PET/CT examination;(2) multivariate analysis and diagnostic value affecting MVI of HCC;(3) treatment and follow-up.Follow-up using outpatient examination and telephone interview was performed to detect the postoperative patients' survival up to November 2017.Measurement data with normal distribution were represented as (x)±s,and comparisons between groups were evaluated with the independent-sample t test.Measurement data with skewed distribution were described as M (Qn),and comparisons between groups were analyzed using the independent-sample rank sum test.Comparisons of count data were analyzed using the chisquare test.Logistic regression analysis was performed in variables with statistical significance.The inclusion criteria was 0.05 and exclusion criteria was 0.10 according to Backward (LR) method for screening variables.Receiver Operating Characeristic (ROC) curve analysis was used to evaluate the diagnostic value using MVI as a diagnostic standard.Results (1) Results of 18F-FDG PET/CT examination:of 51 HCC patients,tumors located in the right lobe,left lobe and caudate lobe of the liver were respectively detected in 37,12 and 2 patients.CT examinations of 51 HCC patients:HCCs showed the hypodense shadow or slightly hypodense shadow in liver and were round-like,and some of the larger lesions were irregularly conglomerate,with a relatively clear tumor-liver boundary;tumor necrosis area showed patchy and irregular lower density,with small lesions around the port of tumors.Of 51 patients,34 were positive on PET and 17 were negative on PET,and some necrotic areas showed no uptake and located in the center of tumors.There was no abnormal 18 F-FDG uptake in other parts of the whole body.The maximum diameter of tumor was (6± 3)cm.The maximum standardized uptake value (SUVmax),and ratio of SUVmax of tumor to SUVmax of liver (SUVmax T/L) in all the lesions were 6.38±4.91 and 2.42±1.93,respectively.The mean standardized uptake value (SUVmean),metabolism of volume (MTV),total lesion of glycolysis (TLG) of 40 patients were 4.30± 2.46,43.82 cm3 (8.97 cm3,219.13 cm3) and 165.73 (28.26,794.50),respectively,and software could not automatically delineate lesions in other 11 patients due to low metabolism.Delayed imaging was found in 21 patients,and the delayed SUVmax and retention index (RI) were 7.22±6.26,19.66％ (-7.10％,50.84％),respectively.The cases with positive and negative on PET were 18,3 in the positive MVI group and 16,14 in the negative MVI group,respectively,with a statistically significant difference between groups (x2=5.829,P＜0.05).The maximum diameter of tumor in the positive MVI group and negative MVI group was respectively (7.7±2.9)cm and (5.2±3.1)cm,with a statistically significant difference between groups (t=-2.930,P＜0.05).(2) Multivariate analysis and diagnostic value affecting MVI of HCC:the results of multivariate analysis showed that maximum diameter of tumor was an independent factor affecting MVI of HCC (OR=1.276,95％ confidence interval:1.028-1.585,P＜0.05).The area under the ROC curve of the maximum diameter of tumor was 0.723 using MVI as a diagnostic standard.The sensitivity,specificity and Youden index were respectively 90.5％,50.0％ and 0.405,with 4.55 cm as the critical value.(3) Treatment and followup:all 51 patients underwent tumor resection.Twenty-two patients were followed up for 25 months (range,12-46 months).The 1-and 2-year overall survival rates were 81.8％ (18/22) and 63.6％ (14/22),respectively.The 1-and 2-year tumor-free survival rates were 59.1％ (13/22) and 45.5％ (10/22),respectively.Conclusion The positive rate on PET of 18F-FDG PET/CT examination in HCC patients with positive MVI is higher than that in HCC patients with negative MVI,and the maximum diameter of tumor is an independent factor predicting MVI of HCC,with a certainly reference value.
ABSTRACT
Objective To investigate the inhibitory effect of 188 Re-labeled BaGdF5-poly ( ethylene glycol) ( PEG) nanoparticles ( NPs) on hepatoma cells, and explore the application of the radiolabeled NPs for SPECT imaging. Methods BaGdF5-PEG NPs were synthesized by hydrothermal method, and were fur-ther radiolabeled with 188Re using diethylene triamine pentaacetic acid (DTPA) as a coupling agent. The human hepatoma cells SMCC 7721 were treated with different concentrations of BaGdF5-PEG NPs, 188 ReO-4 or 188Re-DTPA-BaGdF5 NPs (14.8, 74.0, 370.0×104 Bq/ml) for 24 h, and then the cell proliferation rates were measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. 188ReO-4 and 188 Re-DTPA-BaGdF5 NPs were administrated into normal rabbits via the ear vein, respectively. For the former, static SPECT/CT imaging were performed at 30, 60 min post-injection, and for the latter, dynamic SPECT images were captured within 10 min, and static SPECT/CT images at 30, 60, 120 min post-injec-tion. The rabbit VX2 tumor model was established, and a microcatheter was inserted into hepatic artery via the rabbit femoral artery, and then the mixture of 188 Re-DTPA-BaGdF5 NPs and lipiodol was injected into the tumor region. SPECT/CT imaging for VX2 tumor was performed at 30 min later. Data were analyzed by two-sample t test. Results The BaGdF5-PEG NPs were nearly square and the particle size was about 10 nm. The labeling yield of 188 Re-DTPA-BaGdF5 was 94.1％ at the optimum conditions. Moreover, it showed high stability in vitro and in vivo. In vitro, BaGdF5-PEG NPs did not exhibit obvious cytotoxicity even at a high concentration. Both 188 ReO-4 and 188 Re-DTPA-BaGdF5 could inhibit the proliferation of SMCC 7721 cells, but 188 Re-DTPA-BaGdF5 showed a significantly stronger inhibitory effect at the doses of 74.0 and 370.0×104 Bq/ml ( t values:4.21,4.09, both P<0.01) . In vivo, 188 ReO-4 was absorbed by maxillary glands and was quickly elimi-nated from blood via the kidneys. The 188 Re-DTPA-BaGdF5 NPs mainly accumulated in the liver and spleen. In addition, retention and accumulation of 188 Re-DTPA-BaGdF5 NPs in the liver tumor could be achieved by using transarterial intervention technique for drug delivery. Conclusion 188Re-DTPA-BaGdF5 NPs have cer-tain killing effects on hepatoma cells in vitro, and with the help of transarterial intervention technique, the NPs can be aggregated within liver tumor, where they not only can be used for SPECT imaging, but also have potential therapeutic effects.
ABSTRACT
Objective To investigate the correlativity between elasticity modulus and pathological severity in chronic pancreatitis (CP).Methods Twenty-one pigs were divided randomly into experimental group (n=18) and control group (n=3) using random number method.The main pancreatic duct (MPD) was incompletely ligated to establish the CP model.In control group, MPD was not ligated.The animals were killed in batches at 4th, 8th and 12th week after surgery.The pancreatic tissue was taken for elasticity modulus test and pathological examination, and the pigs were classified into control, mild, moderate and severe groups based on the severity of fibrosis.Cell density, fat infiltration and extracellular edema were observed and classified into mild and severe.The difference of elasticity modulus among different groups were compared by Variance analysis, the correlation between pancreatic fibrosis and elastic modulus was analyzed with Spearman correlation analysis, and ROC curve was used to evaluate its efficacy of diagnosing CP.Results Sixteen CP models were established successfully expected for 2 deaths (mild, n=7;moderate, n=2 and severe, n=7).All of the control group (n=3) showed normal pancreas.The elasticity modulus of control, mild and moderate to severe group were 0.4268±0.0566, 0.3203±0.0518 and 0.2235±0.0685, respectively.The difference between the groups was statistically significant (F=13.658,P0.05).Conclusions The elasticity modulus can be used to detect the pathological changes of CP, and evaluate the CP pathologic grades.
ABSTRACT
Objective To evaluate the feasibility of dopamine D2 receptor imaging agent (s)-(-)-N-(1-allylpyrrolidine-2-N-methyl)-5-(3-18F)-2,3-dimethoxy Benzamide (18F-Fallypride) for targeting islet cell imaging.Methods (1) Cytology experiment:Islet cells of 15×103 cells/well were incubated with 3.70 kBq/well 18F-Fallypride for 1 h and the uptake rate of cells was calculated (cell counts/(supernatant counts + cell counts)× 100％).Under the same experiment conditions,6 inhibiting groups were administrated with different concentration of dopamine inhibitors droperidol (1.0× 10-6,4.0× 10-6,2.0× 10-5,1.0× 10-4,5.0× 10-4 and 1.0× 10-3 mol/L,respectively).After 30 min,3.70 kBq of 18F-Fallypride was added to each inhibiting group,and the inhibiting rate was calculated.(2) Autoradiography:18 normal ICR mice were divided into 6 groups.For group A,ICR mice were injected with 18F-Fallypride (55 ± 5) MBq/mice through tail vein.For the other 5 inhibiting groups (group B-F),ICR mice were injected with different doses of droperidol (0.2,0.4,0.6,0.8 and 1.0 mg/kg,respectively),and after 30 min 18F-Fallypride were injected through tail vein.Ten minutes later,pancreas of ICR mice was taken for preparation of tissue section autoradiography.The data were analyzed by one-way analysis of variance and the least significant difference t test.Results (1) The 18F-Fallypride uptake rate of control group was (18.40± 1.21) ％.The uptake rates of inhibiting groups were (16.11±1.37)％,(15.76±0.99)％,(13.90±1.02)％,(8.86±0.73)％,(7.26±0.62)％ and (6.92±0.58)％,respectively,which decreased with the decreasing concentration of droperidol (F=50.01,P＜0.01).When the concentration of droperidol was 1.0× 10-4 mol/L,the uptake rate reached the lowest with inhibiting rate of 51.85％.(2) The autoradiography showed that the pancreas gray scale value of group A was 1.21×106 digital light units (DLU)/mm2.The pancreas gray scale value of groups B to F decreased with increasing concentration of inhibitor:0.93× 106,0.77× 106,0.59× 106,0.32× 106 and 0.25×106 DLU/mm2,respectively.Conclusions 18F-Fallypride may specifically and efficiently bind to dopamine receptors of islet cells.It may be a potential tracer for islet cells imaging.
ABSTRACT
Objective To investigate the correlativity between secretin-stimulated magnetic resonance cholangiopancreatography (sMRCP) findings and pathological severity in a swine chronic pancreatitis (CP) model. Methods Thirty-nine swine were divided randomly into control group (n=12) and experimental group (n= 27). In experimental group, the main pancreatic duct (MPD) was incompletely ligated to establish the model of obstructive CP. In control group, laparotomy was performed but without ligating the MPD. At the 4th, 8th and 12th week after modeling, one third swine of each group were undergone a series of dynamic sMRCP scans before (0 min) and at 1, 3, 5, 7, 9, 11 min after administration of secretin (0.6 μg/kg). And the MPD diameter and duodenum filling (DF) degree were measured. All survivals were sacrificed to pathological examination including HE and Van Gieson staining for histopathological grading. According to pathological severity, swine were divided into normal group, mild CP group and moderate to severe CP group. MRI features and indexes, including baselined diameter (BD), end diameter (ED), maximum diameter (MD), the largest expansion rate (LER), time to peak (Tpeak) and end change rate of pancreatic duct and duodenal filling (DF) scores were measured. The relationships between pathological grading and sMPCP indexes were analysed. The comparison of sMRCP data among the 3 groups were used ariance analysis, χ2 test and U test. Correlations between sMPCP indexes and pathological severity were tested using Spearman rank correlation coefficients. The diagnostic efficiency of sMRCP indexes were evaluated by ROC method. Results (1) In experimental group, 22 CP models were established and 19 CP swine (mild CP, n= 8; moderate and severe CP, n=11) were performed sMRCP successfully. Eleven swine in normal group were obtained satisfactory MRCP images. (2) sMRCP results:BD of 3 groups were (1.56 ± 0.46),(2.95 ± 1.17),(7.41 ± 1.91) mm, respectively. ED were (1.49 ± 0.31),(2.96 ± 1.17) and (7.37±1.90) mm, respectively. MD were (2.39±0.43),(3.91±1.27) and (7.86±1.87)mm, respectively. The median of LER were 42.10%, 34.85% and 6.58%, respectively. The median of DF scores were 3, 3, 2, respectively. The differences of above indexes have statistically significance (P values were all0.05),and no correlation with pathological severity(P values were all>0.05).For differential diagnosis between normal and mild CP, the area under ROC of BD, ED, MD, LER and DFscores were 0.915, 0.977, 0.926, 0.778 and 0.472, respectively and differential diagnosis between mild CP and moderate to severe CP group, the area under ROC were 0.966,0.966,0.960,1.000 and 0.915, respectively. Conclusions sMRCP findings of CP have characteristics and could be used for in vivo evaluation on the CP pathologic grades.
ABSTRACT
Objective To investigate the diagnosis and differential diagnosis value of multisequences magnetic resonance imaging (MRI) in autoimmune pancreatitis (AIP).Methods The MRI data of twelve AIP patients were retrospectively analyzed.The sequences of MRI included T1 weighted imaging,T2-weighted imaging,magnetic resonance cholangiopancreatography (MRCP),diffusionweighted imaging (DWI) and dynamic enhancement images.The location and involving extent of lesions,signal,patterns of dynamic enhancement,changes of pancreatic and biliary duct,pseudo-capsule sign and other accompanying signs were observed.Twelve pancreatic cancer patients and twelve other patients with normal pancreas were set as controls.The imaging signs of AIP group and pancreatic cancer group were compared with Fisher's exact test.On the sequence of DWI,the apparent diffusion coefficient (ADC) values of pancreatic interested region of the three groups were tested and compared with least significant difference t test.At each period of enhanced MRI,the intensity ratios of pancreatic interested region to the left paraspinal muscle at the same level of the three groups were measured and compared with Pillai's Trace test.Results Among 12 patients with AIP,seven were diffused lesion,four were localized lesion,and one was multiple lesions.Among 12 pancreatic cancer patients,one was diffused lesion,and eleven were localized lesion.The difference of these two groups was statisfically significant (Fisher's exact test,P＜0.01).Among 12 AIP patients,on the T1-weighted image,intensity decreased in nine lesions,two cases without obvious intensity decreasing,and one case unevenly increased.On the T2 weighted image,intensity slightly increased in nine lesions,equal in one case,and slightly lowered in two cases.The ADC value of the lesions of AIP group ((1.011 ± 0.118) × 10 3 s/mm2) was lower than that of normal pancreas group ((1.489 ± 0.072) × 10 3 s/mm2) and pancreatic cancer group ((1.274 ± 0.120) × 10 3 s/mm2),and the differences were statistically significant (t=-11.793,-4.300; both P＜0.01).Among 12 AIP patients,the pancreatic duct of the lesions was irregular segmental sclerosis and stenosis in four patients.Pseudo-capsule sign around the lesions of pancreas was seen in seven patients.Among 12 pancreatic cancer patients,the pancreatic duct of the lesions was stenotic in two patients while the pseudo-capsule sign wasn't found.The differences of these two groups were statistically significant (Fisher's exact test,both P＜0.01).Dynamic enhanced MRI showed that enhancement patterns of the lesions of both AIP and pancreatic cancer presented progressive enhancement.However,during the balanced period,the signal intensity ratio of AIP group (3.34±1.40) was significantly higher than that of pancreatic cancer group (2.38 ± 0.18),and the difference was statistically significant (F =60.703,P ＜ 0.01).Conclusion Combination of a variety of sequences of MRI can help to fully reflect the pathological and biological characteristics of AIP and increase the accuracy of diagnosis.
ABSTRACT
Objective To compare the therapeutic effects of CT-guided ~(125)I seed implantation with simple Gemcitabine chemotherapy for the treatment of unresectable pancreatic carcinoma. Methods Forty-six untreated patients with unresectable advanced pancreatic carcinoma were randomly divided into two groups: group A (n = 22), treated with ~(125)I seed implantation and group B (n = 24), treated with intravenous chemotherapy using Gemcitabine only. The clinical benefit response (CBR), objective tumor response (OTR), safety and the improvement of living quality were evaluated and analyzed. Results Three months after the treatment, the OTR rate of group A and group B was 45.5% and 8.33% respectively (P < 0.05). The CBR rate of group A and group B was 47.1% and 25% respectively (P < 0.05). No significant difference in PFS between group A and group B (P > 0.05). And also, the incidence of hematological toxicity and complication between two groups were of no significant difference. Conclusion For the treatment of advanced unresectable pancreatic carcinoma, both simple Gemcitabine chemotherapy and ~(125)I seed implantation are able to obtain a moderate objective response, although ~(125)I seed implantation seems to be more effective than Gemcitabine in improving the living quality and survival rate.
ABSTRACT
Objective To investigate the feasibility and safety of percutaneous interstitial implantation of ~(125)I seeds into the pancreas of pig under CT-guidance. Methods Twelve healthy pigs were equally divided into 6 groups.~(125)I seed implantation into the pancreatic tail under CT-guidance was performed in pigs of study groups (group A-E), while ghost seeds that contained no radioactive materials were used in the control group (group F). Imaging examination and laboratory tests, including serum amylase, hepatic and renal functions, were conducted before and 1, 7, 15, 21, 30, 60 days after the procedure. Every two pigs (group A-E) were sacrificed each time at 15, 30, 45, 60, and 75 days after treatment, and specimens of pancreas, duodenum, liver, kidney, etc. were collected and sent for pathologic examination. Results The ~(125)I seeds were successfully implanted in all pigs. During the follow-up period, no severe complications occurred. Imaging and pathologic studies demonstrated that in study groups necrosis of pancreatic tissue appeared around the implanted ~(125)I seeds in 15 days, the necrosis area increased significantly in 45 and 60 days, and in 75 days the necrosis size remained quite the same as seen in 60 days. No necrosis was found in the control group (group F) 60 days after treatment. No serious complications, such as effusions, hemorrhage or necrosis of the adjacent duodenum, stomach, liver or kidney, occurred 75 days after the treatment. Conclusion Percutaneous interstitial implantation of ~(125)I seeds into the pig's pancreas under CT-guidance is safe and feasible.
ABSTRACT
Objective To establish a big animal model of secondary infection of acute necrotizing pancreatitis (ANP). Methods Thirty young pigs were allocated to experiment group ( n = 20 ) or control group (n = 10). The ANP model was induced by retrograde injection of a mixture solution of 5% sodium taurocholate and 5% trypsin (0. 5 ml/kg body weight) into the main pancreatic duct and ligation of the proximal end of the main pancreatic duct, and then the second step was injecting 3 ～ 4 ml living Escherichia coli (E coli) suspension (108/ml) to the necrotic area of the pancreas by fine needle aspiration technique under CT guidance in the experiment group, and by injecting 3 ～ 4 ml inactivated E coli in the control group using the same method. Multi-slice spiral CT dynamic enhanced scan was performed in both groups 1 day and 2 or 3 days after ANP modeling and 5 days after bacterial injection to calculate the CTSI score. Serum amylase, blood WBC count and blood bacterial culture was performed in both groups. 5 days later, the animals were scarified to observe the infected or necrosis foci, and perform smear, bacterial culture and pathologic examinations of the tissue around the infected or necrosis foci. Results The ANP secondary infection model was successfully established in 16 of the 20 animals in the study group, with a success rate of the 80.0% (16/20). There were 17 foci where the positive rate of bacterial culture was 100% (17/17 foci), and the success rate of blood bacterial culture was 68.8%(11/16). In the control group, the ANP model was established successfully in 7 of 10 animals (70%), except for one case of contamination, only one foci was identified;the positive rate of bacterial culture and the success rate of b|ood bacterial culture was 14.3% (1/7). Serum amylase and white blood WBC count increased with similar trends, WBC count in the study group was significantly higher than that in the control group (P<0.01). The mean CT severity index(CTSI) was all ≥4 in beth groups, indicating the severity was moderate to severe. Conclusions A stable and reliable model of secondary infection of ANP in big could be established satisfactorily by injecting active E. coli into the pancreatic necrosis tissue under CT guidance, which helps further pathogenic mechanism studies and clinical studies, especially imaging studies.