ObjectiveTo conduct a meta-analysis comparing the accuracy of artificial intelligence (AI)-assisted diagnostic systems based on 18F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT) and structural MRI (sMRI) in the diagnosis of Alzheimer's disease (AD). MethodsOriginal studies dedicated to the development or validation of AI-assisted diagnostic systems based on 18F-FDG PET/CT or sMRI for AD diagnosis were retrieved from the Web of Science, PubMed, and Embase databases. Studies meeting the inclusion criteria were collected, and the risk of bias and clinical applicability of the included studies were assessed using the PROBAST checklist. The pooled sensitivity, specificity, and area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated using a bivariate random-effects model. ResultsTwenty-six studies met the inclusion criteria, yielding a total of 38 2×2 contingency tables related to diagnostic performance. Specifically, 24 contingency tables were based on 18F-FDG PET/CT to distinguish AD patients from normal cognitive (NC) controls, and 14 contingency tables were based on sMRI for the same purpose. The meta-analysis results showed that for 18F-FDG PET/CT, the AI-assisted diagnostic systems had a pooled sensitivity, specificity, and SROC-AUC of 89% (95%CI 88% to 91%), 93% (95%CI 91% to 94%), and 0.96 (95%CI 0.93 to 0.97), respectively. For sMRI, the AI-assisted diagnostic systems had a pooled sensitivity, specificity, and SROC-AUC of 88% (95%CI 85% to 90%), 90% (95%CI 87% to 92%), and 0.94 (95%CI 0.92 to 0.96), respectively. ConclusionAI-assisted diagnostic systems based on either 18F-FDG PET/CT or sMRI demonstrated similar performance in the diagnosis of AD, with both showing high accuracy.
With the in-depth study of the pathophysiological changes of ischemic myocardium, some experimental studies have found that in many patients with coronary heart disease, severe lesions and long duration of diseases which do not recover due to revascularization, are mainly related to the viable myocardium in the affected area. Survival myocardium refers to those perfusion defect-induced dysfunctional but not dead cardiomyocytes, including stunned myocardium and hibernating myocardium. Therefore, accurate assessment of viable myocardium is important for the development of clinical treatment options and prognosis assessment of such patients. Positron emission tomography/computed tomography (PET/CT) can evaluate the survival of hibernating myocardium and quantitatively analyze it. Thus PET/CT can provide useful information for the possibility of myocardial function recovery after revascularization, treatment options and prognosis evaluation.
Solitary pulmonary nodule (SPN) is defined as a rounded opacity≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients' age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered.
Objective To introduce the current study on 18F-fluorodexyglucose positron emission tomography (18F-FDG PET) scanning in diagnosis and treatment of carcinoma of large intestine. Methods The literatures about 18F-FDG PET scanning in diagnosis and treatment of carcinoma of large intestine in recent years were reviewed. Results 18F-FDG PET scanning is superior to CT and MRI in identificating carcinoma of large intestine recurrence, metastasis in the early stage after operation and staging carcinoma of large intestine. Conclusion 18F-FDG PET scanning may be one of the accessory examinations in carcinoma of large intestine and may be helpful for the choice of treatment.
Objective To investigate the characteristic of the expression of facilitative glucose transporter 1 （Glut1） in bronchial aveolar carcinoma （BAC） and the relationship between expression of Glutl and fluorine-18 fluorodeoxyglucose （18F-FDG） uptake. Methods Twenty patients with BAC were imaged with 18F-FDG positron emission tomography （PET） before surgery. Maximum standard uptake value （SUVmax） and mean standard uptake value （SUVmean ） of tumor and standard uptake value of normal lung （SUVIung） were measured. The expression of Glutl was studied in paraffin sections by streptavidin peroxidase （SP） immunohistochemistry. Results All tumors of the patients could be detected by ^18F-FDG-PET. 18F-FDG uptake of tumor was higher than that of normal lung （SUV SUV and SUVlong were 3.09± 1.35, 2.37±1.03 and 0.39±0.09 respectively）. The expression of Glutl were positive in all tumors （73. 8%± 14. 8% of positive cell rate, 2. 8 ± 0. 9 grade of staining intensity）. Predominantly cytoplasm positive with weak staining intensity were observed in many tumors. Glutl negtive were observed in normal bronchial and lung parenchyma. Positive correlations were found among 18F-FDG uptake, Glut1 expression and tumor size （P〈0. 01）. Conclusion Glutl expression with peculiarity in BAC is correlate with 18F-FDG uptake.
ObjectiveTo analyze the influencing factors for image quality of 18F-deoxyglucose (FDG) positron emission tomography (PET)/CT systemic tumor imaging and explore the method of control in order to improve the PET/CT image quality.
MethodsRetrospective analysis of image data from March to June 2011 collected from 1 000 18F-FDG whole body tumor imaging patients was carried out. We separated standard films from non-standard films according to PET/CT image quality criteria. Related factors for non-standard films were analyzed to explore the entire process quality control.
ResultsThere were 158 cases of standard films (15.80%), and 842 of non-standard films (84.20%). Artifact was a major factor for non-standard films (93.00%, 783/842) followed by patients’ injection information recording error (2.49%, 21/842), the instrument factor (1.90%, 16/842), incomplete scanning (0.95%, 8/842), muscle and soft tissue uptake (0.83%, 7/842), radionuclide contamination (0.59%, 5/842), and drug injection (0.24%, 2/842). The waste film rate was 5.80% (58/1 000), and the redoing rate was 2.20% (22/1 000).
ConclusionComplex and diverse factors affect PET/CT image quality throughout the entire process, but most of them can be controlled if doctors, nurses and technicians coordinate and cooperate with each other. The rigorous routine quality control of equipment and maintenance, patients’ full preparation, appropriate position and scan field, proper parameter settings, and post-processing technology are important factors affecting the image quality.
ObjectiveTo systematically review the diagnostic value of FDG-PET, Aβ-PET and tau-PET for Alzheimer ’s disease (AD).MethodsPubMed, EMbase, The Cochrane Library, CNKI, WanFang Data, VIP and CBM databases were electronically searched to collect diagnostic tests of FDG-PET, Aβ-PET and tau-PET for AD from January 2000 to February 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies; then, meta-analysis was performed by Meta-Disc 1.4 and Stata 14.0 software.ResultsA total of 31 studies involving 3 718 subjects were included. The results of meta-analysis showed that, using normal population as control, the sensitivity/specificity of FDG-PET and Aβ-PET in diagnosing AD were 0.853/0.734 and 0.824/0.771, respectively. Only 2 studies were included for tau-PET and meta-analysis was not performed.ConclusionsFDG-PET and Aβ-PET can provide good diagnostic accuracy for AD, and their diagnostic efficacy is similar. Due to limited quality and quantity of the included studies, more high quality studies are required to verify the above conclusions.
There are some problems in positron emission tomography/ computed tomography (PET/CT) lung images, such as little information of feature pixels in lesion regions, complex and diverse shapes, and blurred boundaries between lesions and surrounding tissues, which lead to inadequate extraction of tumor lesion features by the model. To solve the above problems, this paper proposes a dense interactive feature fusion Mask RCNN (DIF-Mask RCNN) model. Firstly, a feature extraction network with cross-scale backbone and auxiliary structures was designed to extract the features of lesions at different scales. Then, a dense interactive feature enhancement network was designed to enhance the lesion detail information in the deep feature map by interactively fusing the shallowest lesion features with neighboring features and current features in the form of dense connections. Finally, a dense interactive feature fusion feature pyramid network (FPN) network was constructed, and the shallow information was added to the deep features one by one in the bottom-up path with dense connections to further enhance the model’s perception of weak features in the lesion region. The ablation and comparison experiments were conducted on the clinical PET/CT lung image dataset. The results showed that the APdet, APseg, APdet_s and APseg_s indexes of the proposed model were 67.16%, 68.12%, 34.97% and 37.68%, respectively. Compared with Mask RCNN (ResNet50), APdet and APseg indexes increased by 7.11% and 5.14%, respectively. DIF-Mask RCNN model can effectively detect and segment tumor lesions. It provides important reference value and evaluation basis for computer-aided diagnosis of lung cancer.
Positron emission tomography (PET) is a highly sensitive and low invasive technology for cancer biological imaging. Integrated PET/computed tomography (PET/CT) cameras combine functional and anatomical information in a synergistic manner that improves diagnostic interpretation. The role of 18F FDG PET/CT in differentiated thyroid cancer (DTC) is well established, particularly in patients presenting with elevated thyroglobulin (Tg) levels and negative radioactive iodine scan. This review presents the evidence supporting the use of 18F FDG PET/CT throughout the diagnosis and management of thyroid cancer, and provides suggestions for its clinical uses.
Epilepsy is a clinical syndrome characterized by recurrent epileptic seizures caused by various etiologies. Etiological diagnosis and localization of the epileptogenic focus are of great importance in the treatment of epilepsy. Positron emission tomography-computed tomography (PET-CT) technology plays a significant role in the etiological diagnosis and localization of the epileptogenic focus in epilepsy. It also guides the treatment of epilepsy, predicts the prognosis, and helps physicians intervene earlier and improve the quality of life of patients. With the continuous development of PET-CT technology, more hope and better treatment options will be provided for epilepsy patients. This article will review the guiding role of PET-CT technology in the diagnosis and treatment of epilepsy, providing insights into its application in etiological diagnosis, preoperative assessment of the condition, selection of treatment plans, and prognosis of epilepsy.
