Objective To discuss the impact of an iterative reconstruction algorithm (True X) implemented with point spread function (PSF) on image quality and SUV in 18F-FDG PET, and compare with other reconstruction algorithms.Methods A total of 79 hypermetabolic lesions from 37 cancer patients (23 males, 14 females, age (63.38±15.25) years) were retrospectively studied.The PET images were reconstructed using the following six reconstruction algorithms, including FBP, FBP+TOF, iteration, iteration+TOF, True X, True X+TOF.Paired t test was used for statistical analysis.Results All six reconstruction algorithms showed significant difference in lesion SUVmax.The adoption of PSF increased SUVmax by 15%-16%, and decreased the dispersion of SUV in the liver parenchyma remarkably.Conclusions Lesion SUVmax calculated from different reconstruction algorithms has significant differences.Caution should be taken in using PSF, as it can improve image quality but may also increase lesion SUVmax.

Objective To investigate the feasibility and accuracy of enhanced magnetic resonance pulmonary perfusion imaging(MRPP) in the diagnosis and follow-up of pulmonary embolism(PE). Methods Sixty patients suspected of PE underwent MRPP. Twenty-seven patients also underwent radionuclide perfusion imaging. 22 patients repeated MRPP examination after 3 day to 1 month anticoagulation or thrombolytic therapy. The feasibility and accuracy of MRPP in the diagnosis and follow-up of PE were evaluated according to the transformation rate of signal (TROS), time-signal curve and some parameters of main pulmonary artery(such as peak value of flow,mean flow velocity and flow rate). The t test and rank sum test were used for the statistics. Results MRPP showed a high agreement with radionuclide perfusion imaging. TROS was (2. 86 ± 2. 48 ) vs ( 6. 72 ± 2. 54) ( t = 3. 370, P ＜ 0. 01 ), the peak time was ( 13.98 ±5.60) vs ( 12. 33 ± 3.63 ) s ( t = 3. 930, P ＜ 0. 01 ), the peak value of main pulmonary blood flow was (60.39 ± 15. 17) vs (69.93±13.22) cm/s(t=2.930, P＜0. 01) and mean flow velocity (11.68±5.46) vs ( 13.54 ± 4. 18 ) cm/s ( t = 2. 380, P ＜ 0. 05 ) before and after anticoagulation or thrombolytic therapy. The flow rate per unit was (80. 57 ± 24. 87) vs ( 85.48 ± 11.81 ) ml/s ( t = 0. 86,P ＞ 0. 05 ) . Conclusion MRPP shows a high agreement with radionuclide perfusion imaging and is a useful method for the diagnosis and follow-up of PE.

Objective To investigate the value of 99Tcm-Duramycin SPCET/CT in the detection of vulnerable plaque (VP) in atherosclerotic (AS) rabbit models.Methods Sixteen New Zealand male rabbits were randomly divided into three groups:group A (sham-operated group,n =4),group B (stable plaque group,n =4) and group C (VP group,n =8).Group A was fed on normal diet,and the other 2groups were fed on cholesterol diet for 12 weeks.Femoral artery dissection sham-operation was done in group A and group B,while balloon-induced abdominal aorta wall injury was produced in group C after 2 weeks'feeding.Animals were injected with 99Tcm-Duramycin (74 MBq/kg) and then SPECT/CT imaging was performed at the end of 4,8,and 12 weeks,respectively.Abdominal aortas were explanted for ex vivo imaging and histological characterization of plaque.The apoptosis index (AI) was calculated.One-way analysis of variance was used to analyze data.Results There was no radioactive uptake by the abdominal aorta in each group at the end of 4 weeks and no uptake in group A and group B at the end of 8 weeks.There was slightly uptake radioactive uptake by the abdominal aorta in group B at the end of 12 weeks and in group C at the end of 8 weeks.There was intense uptake at the lesions of AS rabbits in group C at the end of 12 weeks,and the T/NT value significantly higher than that of the other two groups (3.40±0.22 vs 2.12±0.65,2.68±0.18,F=198.775,P＜0.05).The result was confirmed in the ex vivo imaging of the explanted aorta.The AI of group C was significantly higher than that of group A and B ((25.4±6.32) ％ vs (0±0.02)％,(5.3± 1.97)％,F=70.260,P＜0.05).Conclusions 99Tcm-Duramycin scimigraphy could identify the apoptosis of VP in the rabbit AS models.It is a promising non-invasive method to diagnose AS plaques.

Objective To evaluate the cause of ischemia related to myocardial bridge (MB) by using SPECT/CT MPI and CTCA.Methods A total of 294 patients with chest pain,tightness or palpitation undergoing both CTCA and MPI were retrospectively enrolled in this study from March 2008 to March 2013.Among them,49 patients (26 males,23 females,age:32-85 (55.4± 16.6) years) had MB.Locations of MB and myocardial ischemia were recorded.Fused MPI/CTCA was analyzed.If there was no mural atherosclerotic plaque-related stenosis on CAG at the same location of coronary artery where ischemic myocardium was found,then MB was considered as the ischemic cause.Myocardial ischemia rates of different MB locations were compared by x2 test.Results Among 49 patients with MB,3 cases had MB in proximal segment of LAD,34 in mid LAD,4 in distal LAD,3 in septal branch,2 in distal LCX,1 in intermedius,and 2 in mid RCA.There were 41 cases with myocardial ischemia.Myocardial ischemia in 32 cases was caused by MB,including 23 caused by MB in mid LAD.The myocardial ischemia rates of the most common MB location (mid LAD,n =34) and other locations (n =15) were not significantly different (67.6％ (23/34) vs 60.0％ (9/15),x2 =0.27,P＞0.05).Conclusions MB is commonly found in the mid LAD.The myocardial ischemia rates caused by MB is not related the MB location.Hybrid MPI/CTCA could evaluate the sites of coronary MB and myocardial ischemia simultaneously and therefore may be useful to evaluate the relationship between MB and myocardial ischemia.

Objective To study the antitumor effects on human prostate cancer cell lines of a traditional Chinese medicine named atractylodes macrocephala koidz volatile oil in vitro.Methods LNCaP and DU145 cell lines were normally cultured and were divided into 4 control groups including:Blank culture without serum and without cell (group A),Blank culture with serum but without cell (group B),LNCaP cell culture with serum (group C),DU145 cell culture with serum (group D).In the meanwhile,there were 6 experimental groups:adding 50 μg/ml of atractylodes macrocephala koidz volatile oil in culture of group C1 and group D1,250ug/ml in group C2 and group D2,and 500ug/ml in group C3 and group D3.All of the 10 groups were simultaneously cultured in 24-well-plates for 48 hrs,and each group was repeatedly studied for three times.Forty-eight hours later,every 2 × 106 cells of LNCaP or DU145 was seeded into each well and atractylodes macrocephala koidz volatile oil was added in 6 experimental groups,and saline water was added into 4 control groups.Another 48 hrs later,the culture solutions of the 10 groups were separately collected for testosterone (T),estradiol (E2),progesterone (P),vascular endothelial growth factor (VEGF),basic fibroblast growth factor (b-FGF),total prostate specific antigen (tPSA) and free prostate specific antigen (fPSA) analysis with enzyme-linked immunoassay kits.The experiment was repeated for 3 times,and the mean data were statistically analyzed by SPSS One-way ANOVA.Results The growth of cultured cells was found to have been effectively inhibited in group C1 and group D2.The inhibition severity of LNCaP cells was positively related with the drug concentration and time,while DU145 cells could only be highly inhibited (60.96％) after 24hrs drug treatments.In group C and group D,we found that both T were in very low level (0 ng/ml) whereas both E2 were in high levels (269 pg/ml and 239.81 pg/ml,P ＜ 0.05),no distinct differences showed in P; In addition,VEGF,b-FGF and fPSA were all in high values,whose values were 102.96 pg/ml and 1763.40 pg/ml,0.26 ng/ml and 6.41 ng/ml,0.16 ng/ml and 0.44 ng/ml,respectively; DU145 cells had higher values than LNCaP cells (P ＜ 0.05).As regard to the 6 experimental groups,in the groups C1,C2,C3 and D3,we found that T had been unexpectedly increased from 0 to 0.37 ng/ml (P ＜ 0.05),E2 continuously elevated from 239.81 pg/ml to 649.90 pg/ml (P ＜0.05),surprisingly P were also increased from 0.98 ng/ml to 9.83 ng/ml (P ＜0.01).On the contrary,VEGF,b-FGF and fPSA levels were all graduallydecreased,dropping down to 47.79 pg/ml and 59.56pg/ml,0 and 1.79 ng/ml,0 and 0.11 ng/ml,respectively; nevertheless,in group C2 and group D2,fPSA values were surprisingly increased from 0 and 0.04 ng/ml up to 1.78 ng/ml and 0.23 ng/ml respectively.Conclusions Atractylodes macrocephala koidz volatile oil has certain anti-tumor effects on human prostate cancer.Compared with LNCaP cells,DU145 cells have many different characteristics in sex hormone,cytokine and PSA expressions.

Objective To investigate the diagnostic value of dual-energy CT pulmonary angiography (DE-CTPA) and dual-energy CT lung perfusion (DE-CTLP) in the assessment of pulmonary embolism comparing with pulmonary ventilation-perfusion scintigraphy. Methods Fifty patients suspected of PE (26 males, 24 females) underwent both DE-CTPA, DE-CTLP and pulmonary ventilation-perfusion scintigraphy. The results were compared and the correlation between the intravascular clots in DE-CTPA and the perfusion defects in DE-CTLP was analyzed. The sensitivity, specificity and accuracy of DE-CTLP for PE were assessed according to scintigraphic results which was considered as a "gold" standard. Result ( 1 ) Of 50 cases,920 segments in 46 cases were diagnostable, 4 cases were not included because of the poor image quality. lntravascular clots were found in 262 segments on DE-CTPA and perfusion defects in 266 segments were identified on DE-CTLP, while 268 segments were positive on scintigraphy. (2) The perfusion defects on DE-CTLP were correlated well with the clots on CTPA ( r = 0. 883, P < 0. 01 ). The Dual energy CT Lung perfusion imaging had a good consistence with scintigraphy (Kappa = 0. 940, P <0. 01 ). The sensitivity, specificity, positive and negative predictive value were 96. 2% (279/290), 98.0%(641/654), 95. 5% (279/292) and 98. 3% (641/652), respectively. (3)The radiation dose of DE-CTPA and CE-CTLP scan was(4. 37 ± 0. 47) mSv by using CareDose 4D technique. Conclusion DE-CTPA and CE-CTLP can provide pulmonary vascular morphology and parenchyma perfusion information which are useful and valuable for the diagnosis of PE.

Objective To investigate the feasibility of a novel molecular probe 99Tcm-3P4-RGD2 in evaluating arterial plaque stability after atorvastatin intervention in rabbits with SPECT/CT. Methods Eighteen male New Zealand rabbits were randomly divided into group A (stable plaque), group B (vulnerable plaque), and group C (vulnerable plaque with statin intervention). All rabbits were fed with high-fat food for 12 weeks. After high-fat feeding for two weeks, sham surgery was performed on group A. In the meantime, abdominal aorta injury was performed on group B and group C. After that, rabbits of group C were given oral atorvastatin (2.5 mg·kg-1·d-1). 99Tcm-3P4-RGD2 SPECT/CT imaging was performed on each group at the end of 4, 8 and 12 weeks. T/NT ratios were calculated. Animals were sacrificed at the end of 12 week after imaging studies. The abdominal aortas were collected, imaged with SPECT/CT, and evaluated by pathological HE staining and immunohistochemical analysis. MVD was calculated. Differences among 3 groups were analyzed using one-way analysis of variance. Results There was no significant radioactive uptake in the abdominal aortas of three groups on the 4th week′s imaging. The radioactive uptake in abdominal aortas increased slightly on the 8th week, with the highest radioactive uptake in group B. The radioactivity in abdominal aortas of the 3 groups maintained increasing on the 12th week, with T/NT ratios of 1.579±0.217, 1.873±0.226 and 1.524±0.237, respectively (F=8.984, P<0.05). In ex vivo abdominal aorta images, especially images of group B, radioactivity in lesion sites was higher than that in normal tissue. Accordingly, results of HE staining showed that artery plaques of group A and group C were grade Ⅱ and group B was grade Ⅳ. The MVD of group A, B and C was 8.17±1.17, 15.86±1.07 and 7.17±1.60, respectively (F=9036, P<0.05). Conclusion 99Tcm-3P4-RGD2 SPECT/CT imaging has a high sensitivity in the evaluation of arterial plaque stability after statin intervention in rabbits.

Objective:To evaluate the effect of remote ischemic conditioning (RIC) on left ventricular (LV) myocardial perfusion, myocardial viability, LV remodeling, regional and global LV function serially following acute myocardial infarction (AMI) in Chinese mini-pigs.Methods:AMI was established in 12 Chinese mini-pigs (8 males, 4 females; age: 6-8 months) and they were randomly divided into RIC group ( n=6) and non-RIC group ( n=6). RIC was performed in pigs by blood pressure inflation on the lower limbs for 5 min period and 4 cycles immediately after surgery. A series of myocardial perfusion imaging and gated 18F-fluorodeoxyglucose (FDG) myocardial metabolism PET/CT imaging were performed longitudinally at the 1st, 14th, 28th and 56th days after AMI, and parameters including total perfusion defect (TPD), hibernating myocardium (HM), Scar, left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), summed motion score (SMS), summed thickening score (STS) and changes of these parameters were obtained. Independent-samples t test and Mann-Whitney U test were used to analyze data. Results:Nine Chinese mini-pigs survived after surgery and were performed imaging. Compared to non-RIC group ( n=4), HM at the 28th ((6.0±2.4)% vs (17.0±4.6)%; t=-4.158), TPD 14th-1st ((-11.8±5.4)% vs 9.0%(4.5%, 15.0%); z=2.449), TPD 28th-1st ((-15.3±3.9)% vs (12.0±3.0)%; t=-10.071), TPD 56th-1st ((-18.0±6.5)% vs 9.0%(4.5%, 12.0%); z=2.449), HM 28th-1st ((-10.5±6.9)% vs (8.3±2.1)%; t=-4.507), HM 56th-1st (-15.0%(-17.5%, -8.5%) vs 2.0%(0%, 7.0%); z=2.449) and LVEDV 14th-1st (-0.5(-2.5, 0) ml vs (13.0±4.4) ml; z=2.470) were reduced in RIC group ( n=5; all P<0.05). Conclusion:RIC can improve myocardial perfusion, delay LV remodeling in the acute stage and salvage hibernating myocardium in the subacute stage and chronic stage.

Objective To evaluate the features of myocardial perfusion imaging (MPI) in patients with homozygous familial hypercholesterolemia (HoFH) and its influence factors.Methods Forty-two consecutive HoFH patients (21 males,21 females;average age:(14.8±8.4) years) were retrospectively enrolled in this study from June 2010 to November 2016.Diagnosis was proved by clinical and chromosome tests,and all patients underwent ATP stress and rest 99Tcm-methoxyisobutylisonitrile (MIBI) SPECT MPI with a two-day protocol.Summed stress score (SSS) and summed rest score (SRS) were acquired,and summed difference score (SDS;SSS-SRS) was calculated.Relations between SSS,SRS,SDS and age,lipid profile were analyzed.Two-sample t test,x2 test,multiple linear regression analysis and multivariate logistic regression were used to analyze the data.Results There were 24 patients with positive MPI results (SSS≥1),and females (76.2％,16/21) showed more positive MPI results than males (38.1％,8/21;x2=6.22,P＜0.05).Eighteen patients had negative MPI results.There were 6,8,10 patients with MPI positive results in ＜ 10 years group (n =14),10-18 years group (n =14) and ≥ 19 years group,respectively (x2=2.33,P＞0.05).Positive electrocardiograph (ECG) in ATP stress test was observed in 9 females (42.9％,9/21) and 3 males (14.3％,3/21;x2 =4.20,P＜0.05).Sixty-three (8.8％,63/714) abnormal myocardial perfusion segments (SSS≥ 1) were found,which was mainly (60.3％,38/63) distributed in myocardial regions supplied by left anterior descending branch (LAD).SSS was positively correlated with age and high density lipoprotein cholesterol (HDLC).SRS,SDS were positively correlated with HDLC and age respectively.Multivariate logistic regression analysis indicated that the female was the only independent risk factor to predict positive MPI (odds ratio=5.2,95％ CI:1.363-19.774).Conclusions In HoFH patients,abnormal myocardial perfusion had a rising trend with age increasing.Female patients are more likely to have abnormal MPI.Abnormal myocardial perfusion segments are mainly located in myocardial regions supplied by LAD.Age and gender are influence factors of abnormal MPI in HoFH patients.

Objective To evaluate 18F-fluorodeoxyglucose (FDG) PET/CT in the rabbit model of vulnerable plaques by correlation with 99Tcm-Arg-Gly-Asp (RGD) SPECT/CT imaging,lipid levels,pathological and immunohistochemical results.Methods Sixteen male New Zealand white rabbits were randomly divided into normal diet group (group A,n =4),stable plaque group (group B,n =4) and vulnerable plaque group (group C,n =8) using completely random grouping method.The animals were given abdominal aorta sham operation (groups A and B) or balloon injury of the abdominal aorta (group C) 2 weeks after feeding.Animals were injected with 18F-FDG and 99Tcm-RGD respectively at the end of 4,8 and 12 weeks.PET/CT was performed at 1,2 and 3 h post-injection.SPECT/CT was performed at 30 min post-injection.One rabbit was sacrificed at the end of 4 and 8 weeks after imaging studies,respectively.The others were sacrificed at the end of 12 weeks after imaging studies.All abdominal aortas were harvested.Pathology and immunohistochemistry analysis were performed.The data were analyzed by one-way analysis of variance and Pearson correlation analysis.Results There was no uptake in any group at 4th week and no uptake in group A or group B at 8th week.There was mild uptake in group B at 12th week and group C at 8th week.There was intense uptake in group C at 12th week,whereas both mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) were significantly higher than the other two groups (F values:7.952,14.279,both P＜0.05).In group C,SUVmax(0.43±0.08,0.68±0.06,1.74±0.63) and SUV (0.37±0.03,0.56±0.03,1.26+0.23) had significant difference at 3 h post-injection for imaging at 4th,8th and 12th week (F values:10.939,39.747,both P＜0.05).At 12th week,there was a strong correlation between the uptake of 18 F-FDG and target/non-target (T/NT) ratio of 99Tcm-RGD in all groups(r values:0.748,0.709,both P＜0.05).Histopathology results showed that the plaques had rich macrophages and a small amount of smooth muscle cells in group C,little macrophages in group B,while no macrophages in group A.Conclusion 18F-FDG PET/CT might be an effective noninvasive method for early assessment of aortic vulnerability to atherosclerotic plaque.