Atherosclerosis is a vascular inflammatory disease.Vulnerable atherosclerotic plaques mainly lead to severe cardiovascular and cerebrovascular diseases,such as myocardial infarction and stroke.The research on the early diagnosis of vulnerable plaques becomes currently urgent.As a noninvasive molecular modality,the nuclear medicine imaging (with specific radiolabeled probes) has been used for the detection of unstable plaques,and for the evaluation of therapeutic effect of anti-atherosclerotic drugs.Nuclear imaging techniques for detecting metabolic activity,inflammation,hypoxia,angiogenesis,apoptosis,and microcalcification in unstable plaques are summarized in this review.

Breast-specific gamma imaging (BSGI) and positron emission mammography (PEM) have the high resolution in diagnosing breast lesions with minimum diameter of 3 mm.Both BSGI and PEM are functional imaging modalities,which have no relation with breast tissue density,implanted prosthesis,scar formation and so on.This review elaborates the application of BSGI and PEM in the early diagnosis,treatment protocols and evaluation of efficacy for the patients with breast cancer.

ObjectiveTo evaluate left ventricular systolic synchrony in patients with coronary artery disease (CAD) by speckle tracking imaging (STI) and real-time three-dimensional echocardiography (RT3DE) and investigate the correlation with ECG-gated myocardial perfusion single-photon emission computed tomography (GMPS).MethodsA total of thirteen patients with CAD diagnosed by coronary angiography underwent STI and RT-3DE examinations.The data was analysed off-line using Qlab 8.0 software.STI systolic synchrony indexes included the standard deviation of times to peak strain in radial and circumferial direction in 12 left ventricular segments (Trs12-SD and Tcs12-SD),the standard deviation of times to peak longitudinal strain in 16 left ventricular segments (Tls16-SD).RT-3DE systolic synchrony indexes included the standard deviation of times to the minimum systolic volume in 16 and 12 left ventricular segments (Tmsv16-SD and Tmsv12-SD).GMPS was performed within one week before or after echocardiography.Phase analysis was performed offline using Emory Cardiac Toolbox software.Peak phase,phase SD,bandwidth,skewness and kurtosis were calculated.Results Trs12-SD derived from STI had a positive correlation with phase SD and bandwidth ( r =0.800,P ＜0.05 ; r =0.607,P ＜0.05).Tmsv16-SD derived from RT-3DE had a better positive correlation with phase SD and bandwidth ( r =0.847,P =0.001 ; r =0.890,P ＜0.001).ConclusionsTmsv16-SD derived from RT-3DE had a better correlation with GMPS parameters than STI parameters.RT-3DE assessment of left ventricular systolic parameters is expected to become the ideal synchronization indicator.

Objective To evaluate the role of SPECT cerebral perfusion imaging in assessing the stent implantation for cerebral artery stenosis.Methods A total of 35 patients (31 males,4 females,average age (63.9±10.8)years) with cerebral artery stenosis confirmed by DSA for cerebral artery stent implantation were retrospectively analyzed.99Tcm-ECD cerebral perfusion imaging was performed for all patients before and after stent implantation.The images were realigned and normalized by SPM 2.0 and then analyzed by Brain Search software for quantitative analysis.The brain was automatically separated to 210 functional areas according to Talarich map.The normalized averaged counts (NAC) of each area were calculated and compared with the data of 28 health controls (8 males,20 females,average age (35.8± 9.4) years).Less than 1.96s was defined as low perfusion lesions.The NAC values before and after stent implantation were compared for classifying improved from non-improved group.The mean number of lesions and Essen stroke risk score (ESRS) were analyzed between the two groups.The mean number of lesions and postoperative improvement rate of the internal carotid artery (ICA) occlusion and stenosis were compared.Paired rank sum test,two-sample t test,two-sample rank sum test and x2 test were used for statistical analysis.Results In 35 patients with low perfusion areas,20 were significantly improved after stent implantation.The mean number of lesions in the improved group (34.05± 14.41)was significantly higher than that in the non-improved group (22.93±17.24; t=2.067,P＜0.05).The mean ESRS of the improved patients (14.8)was significantly lower than that of the non-improved patients (22.3,Z=2.24,P＜0.05).The improvement rate of 28 cases with ICA stent implantation was (60.7％,17/28)higher than that of 7 cases with middle cerebral artery (MCA) stent implantation (3/7; P＞0.05).The mean number of the ICA occlusion lesions (34.36± 14.31)was higher than that of the ICA stenosis lesions(31.35± 16.37),but the difference was not statistically significant(t=0.498,P＞0.05).The improvement rate of the ICA occlusion was higher than that of the ICA stenosis (7/11 vs 10/17),but the difference was not statistically significant (P＞0.05).Conclusion SPECT cerebral perfusion imaging and its quantitative analysis can evaluate the low perfusion lesions before stent implantation and predict the perfusion improvement after stent implantation.

Objective To evaluate the diagnostic value of 18F-FDG PET/CT in patients with pancreatic neoplasm.Methods Fifty-three patients (36 males,17 females; age:(60.3±8.9) years) who underwent 18F-FDG PET/CT examination for suspected pancreatic tumor were retrospectively analyzed.Thirtytwo of them underwent dual-time point imaging.The characteristics of PET/CT images and serum CA19-9 were reviewed.Pathological results were used as a gold standard for evaluating the diagnostic value of PET/CT.Two-sample t test,paired t test and ROC curve analysis were used for data analysis.Results Thirtynine patients were finally diagnosed with pancreatic cancer and the other fourteen patients with benign disease.With SUVmax cutoff value of 3.13,the sensitivity and specificity of single-time point 18F-FDG PET/CT for diagnosis of pancreatic cancer were 92.3％ (36/39) and 9/14,respectively.The SUVmax was significant different between pancreatic cancer group and benign disease group (6.16±2.89 vs 3.37± 1.58; t =4.46,P＜0.01).Combined with the level of CA19-9,the diagnostic sensitivity and specificity were 69.2％ (27/39)and 13/14,respectively.The SUVmax of the early scan (5.45±2.43) was significantly different from that of the delayed scan (6.87±2.93) in pancreatic cancer group (t =8.25,P＜0.01),whereas no difference could be found in the benign group (3.18±1.28 vs 4.18±2.49; t=2.24,P＞0.05).With the SUVmax cutoff value of 3.3,the sensitivity,specificity and accuracy in the early scan were 87.0％ (20/23),6/9 and 81.2％ (26/32),respectively.While with the SUVmax cutoff value of 3.0,the sensitivity,specificity and accuracy in the delayed scan were 95.7％ (22/23),5/9 and 84.4％ (27/32),respectively.Conclusion 18 F-FDG PET/CT is a useful tool in the differential diagnosis of benign from malignant pancreatic diseases.

Objective To identify the effect of blood pool 18F-FDG activity on liver SUV and to investigate the optimal normalization method.Methods PET/CT and common serological examination items from 1 018 subjects were retrospectively collected.Mean SUV of liver and blood were recorded as SUVmean(L) and SUVmean (B),respectively.The difference and quotient of SUVmean(L) and SUV mean (B) were calculated as SUVmean (L-B) and SUVmean (L/B),respectively.CV of SUVmean (L),SUVmean (L-B) and SUVmean(L/B) were calculated to assess their inter-individual variations.Pearson correlation analysis was used to evaluate the relationship of SUVmean(L),SUVmean(L-B),SUVmean(L/B) with SUVmean(B).Multiple linear stepwise regression was performed to identify their vulnerability to common serological examination items.Results CV of SUVmean(L/B) (15.1％) was less than that of SUmean(L) (23.2％) and SUVmean(L-B) (40.6％).Correlation between SUVmean(L) and SUVmean(B) (r =0.820,P＜0.001) was more significant than that between SUVmean(L-B) and SUVmean(B) (r =0.205,P＜0.001) as well as between SUVmean (L/B) and SUVmean (B) (r=-0.376,P＜0.001).Blood glucose and BMI correlated with SUVmean(L) and SUVmean(L/B),but not with SUV (B).Age and HDL correlated with SUVmean(L) and SUVmean(B),but not with SUV (L/B).Fatty liver was significantly associated with SUV mean (L/B) (β =-0.047,P ＜0.001),but not with SUVmean(L) and SUVmean (B).Conclusions 18 F-FDG activity of blood pool affects liver SUV.SUV mean (L/B) is a simple and reliable normalization method since its inter-individual variation and vulnerability to common serological examination items are relatively lower than liver SUV.

Objective To identify impacts of infection status of chronic hepatitis viruses and biochemical parameters of liver function on hepatic FDG uptake.Methods The results of 18F-FDG PET/CT,liver function biochemical tests and hepatic virus tests of 713 healthy adults (504 males,209 females,age 24-74 years) were retrospectively analyzed.Two-sample t test,correlation analysis,partial correlation analysis and multiple linear regression were performed to identify correlations of liver SUV with the biochemical parameters and hepatic viral infection status.Results HBsAg tests were performed in 449 subjects,with the results of 65 (14.5％) positive and 384 (85.5％) negative.HCV antibody tests were performed in 477 subjects,with 53 (11.1％) positive and 424 (88.9％) negative.The average SUV of the total subjects was 1.86±0.38.There was no significant difference of SUV between HBsAg positive group and negative group (t=1.042,P＞0.05),or between HCV antibody positive group and negative group (t=1.283,P＞ 0.05).Serum conjugated bilirubin,globulin and AST were significantly correlated with liver SUVmean(r'=-0.191,-0.087 and 0.132,all P＜0.05).These parameters were independent variables on predicting variance of liver SUV with globulin showing the largest predicting value (standardizedβ' =-0.112,P＜0.05).Conclusions Functional status of liver may affect liver 18F-FDG uptake.Serum conjugated bilirubin,globulin and AST may be the independent variables on predicting variance of liver SUV.Liver functional test results should be taken into consideration when hepatic 18F-FDG uptake is interpreted.

18 F?FDG PET/CT has been increasingly used in diagnosis, staging, treatment response assessment and prognosis prediction of malignant tumors. As the main organ of carbohydrate metabolism, liv?er is commonly taken as reference organ in disease diagnosis and imaging quality control. Hepatic FDG up?take in healthy people is affected by various physiological, potential pathological and imaging technical fac?tors, as well as inter?individual variation. Besides, variation of SUV caused by different calibrating methods cannot be neglected. The factors that affecting hepatic FDG uptake based on findings in recent studies are summarized in this review.

Objective To evaluate the combined impacts of blood glucose and its related metabolic factors on 18F-FDG uptake by liver.Methods A total of 544 subjects (384 males and 160 females, age range 24-73 years) undergoing 18F-FDG PET/CT were recruited in this retrospective study.SUVmean of the right lobe of liver was calculated.Two-sample t test and one-way analysis of variance were performed to compare SUVmean between patients with different genders and BMI levels.Linear correlation analysis, partial correlation analysis and multiple linear regression analysis were conducted to evaluate the relationship between age, injected 18F-FDG dose, blood glucose, serum T3, T4, FT3, FT4, BMR, BMI and liver SUVmean.Results The SUVmean of the liver in males and females were 1.89±0.42 and 1.92±0.38 (t=0.693, P>0.05), but it was significantly different among BMI groups (F=3.056, P<0.05).Age, blood glucose and FT3 were significantly associated with liver SUVmean (r′ values: 0.108, 0.140 and 0.105, all P<0.05) and were independent factors that indicated variation of liver SUVmean (β values: 0.006, 0.070 and 0.088, all P<0.05).Blood glucose was the strongest powerful predicting variable of liver SUVmean (β′=0.154, P<0.001).Conclusions Blood glucose and its related metabolic factors can affect the liver 18F-FDG uptake.Age, FT3, blood glucose are independent factors predicting variation of liver SUVmean.The impact of glucose metabolism status should be considered when assessing liver 18F-FDG uptake.

Carcinoma, Hepatocellular ; blood supply ; diagnostic imaging ; Humans ; Liver Neoplasms ; blood supply ; diagnostic imaging ; Microvessels ; diagnostic imaging ; Neovascularization, Pathologic ; diagnostic imaging ; Tomography, X-Ray Computed ; methods