The image quality, lesion detectability, and acquisition time of 18F-FDG total-body PET/CT in oncological patients.

PURPOSE: The purpose was to investigate the effects of short acquisition time on the image quality and the lesion detectability of oncological 18F-FDG total-body PET/CT. METHODS: Nineteen oncological patients (6/13 women/men, age 65.6 ± 9.4 years) underwent total-body PET/CT on uEXPLORER scanner using 3D list mode. The administration of 18F-FDG was weight-based (4.4 MBq/kg). The acquisition time was 900 s, and PET data were reconstructed into 900-, 180-, 120-, 60-, 30-, and 18-s duration groups. The subjective PET image quality was scored using a 5-point scale (5, excellent; 1, poor) in 3 perspectives: overall quality, noise, and lesion conspicuity. The objective image quality was evaluated by SUVmax and standard deviation (SD) of the liver, SUVmax of the tumor, and tumor-to-background ratio (TBR). The lesion detectability was the percentage of identifiable lesions in the groups of 180 to 18 s using the group 900 s as reference. RESULTS: Our results showed that sufficient and acceptable subjective image quality could be achieved with 60- and 30-s groups, and good image quality scores were given to 180- and 120-s groups without significant difference. For shortened acquisition time, SD was increased, while SUVmax of tumor and TBR remained unchanged. The lesion detectability was decreased with shorter acquisition time, but the detection performance could be maintained until the 60-s group compared with the 900-s group, although the image quality degraded. CONCLUSION: The total-body PET/CT can significantly shorten the acquisition time with maintained lesion detectability and image quality.

Low Dose and Low Contrast Medium Coronary CT Angiography Using Dual-Layer Spectral Detector CT.

The aim of the present study was to investigate the performance of low keV mono-energetic reconstructions in spectral coronary computed tomography angiography (CCTA) using spectral detector CT (SDCT) with reduced contrast media and radiation dose.Sixty patients were randomly assigned to Groups A and B (both n = 30) to undergo CCTA on a dual-layer SDCT with tube voltage 120 kVp and 100 kVp (average tube current: 108.5 and 73.8 mAs, respectively), with contrast media volume of 36 mL used in both groups. The mono-energetic 40-80 keV and conventional 120 kVp images in Group A and conventional 100 kVp images in Group B were reconstructed. Quantitative and qualitative image quality (IQ) were evaluated in the aortic root and distal segments of the coronary arteries.The patient characteristics were not significantly different between the two groups (all P≥ 0.47), nor was the effective radiation dose (1.5 ± 0.3 and 1.4 ± 0.3 mSv, P = 0.20). The quantitative IQ in aorta and coronary arteries of mono-energetic 40-60 keV was superior to conventional 120 kVp and 100 kVp images (all P < 0.05). The noise in spectral images was lower compared to conventional images (all P < 0.01). The subjective IQ score of 40-50 keV images was not significantly different from that of 100 kVp images (P > 0.8).The mono-energetic 40-50 keV reconstructions from spectral CCTA using SDCT provide improved IQ compared to conventional techniques while facilitating reduced radiation dose and contrast media.

Evaluation of a respiratory motion-corrected image reconstruction algorithm in 2-[18F]FDG and [68Ga]Ga-DOTA-NOC PET/CT: impacts on image quality and tumor quantification.

Background: Respiratory motions may cause artifacts on positron emission tomography (PET) images that degrade image quality and quantification accuracy. This study aimed to evaluate the effect of a respiratory motion-corrected image reconstruction (MCIR) algorithm on image quality and tumor quantification compared with nongated/nonmotion-corrected reconstruction. Methods: We used a phantom consisting of 5 motion spheres immersed in a chamber driven by a motor. The spheres and the background chamber were filled with 18F solution at a sphere-to-background ratio of 5:1. We enrolled 42 and 16 patients undergoing 2-deoxy-2-[18F]fluoro-D-glucose {2-[18F]FDG} and 68Ga-labeled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-Nal3-octreotide {[68Ga]Ga-DOTA-NOC} PET/computed tomography (CT) from whom 74 and 30 lesions were segmented, respectively. Three reconstructions were performed: data-driven gating-based motion correction (DDGMC), external vital signal module-based motion correction (VSMMC), and noncorrection reconstruction. The standardized uptake values (SUVs) and the volume of the spheres and the lesions were measured and compared among the 3 reconstruction groups. The image noise in the liver was measured, and the visual image quality of motion artifacts was scored by radiologists in the patient study. Results: In the phantom study, the spheres' SUVs increased by 26-36%, and the volumes decreased by 35-38% in DDGMC and VSMMC compared with the noncorrection group. In the 2-[18F]FDG PET patient study, the lesions' SUVs had a median increase of 10.87-12.65% while the volumes had a median decrease of 14.88-15.18% in DDGMC and VSMMC compared with those of noncorrection. In the [68Ga]Ga-DOTA-NOC PET patient study, the lesions' SUVs increased by 14.23-15.45%, and the volumes decreased by 19.11-20.94% in DDGMC and VSMMC. The image noise in the liver was equal between the DDGMC, VSMMC, and noncorrection groups. Radiologists found improved image quality in more than 45% of the cases in DDGMC and VSMMC compared with the noncorrection group. There was no statistically significant difference in SUVs, volumes, or visual image quality scores between DDGMC and VSMMC. Conclusions: MCIR improves tumor quantification accuracy and visual image quality by reducing respiratory motion artifacts without compromised image noise performance or elongated acquisition time in 2-[18F]FDG and [68Ga]Ga-DOTA-NOC PET/CT tumor imaging. The performance of DDG-driven MCIR is as good as that of the external device-driven solution.

Determining Factors Affecting the Users' Participation of Online Health Communities: An Integrated Framework of Social Capital and Social Support.

As the national awareness of health keeps deepening, online health communities (OHCs) have achieved rapid development. Users' participation is critically important to the sustainable development of OHCs. Nevertheless, users usually lack the motive for participation. Based on the social capital theory, this research examines factors influencing users' participation in OHCs. The purpose of this research is to find out decisive factors that influence users' participation in OHCs, enrich the understanding of users' participation in OHCs, and help OHCs address the issue of sustainable development. The research model was empirically tested using 1277 responses from an online survey conducted in China. Data was analyzed using the structural equation modeling (SEM). We found informational support and emotional support to have significant direct effects over the structural capital, relational capital and cognitive capital of OHCs. Meanwhile, it is observed that relational capital and cognitive capital degree have a significant influence on knowledge acquisition and knowledge contribution of OHCs. For researchers this study provides a basis for further refinement of individual models of users' participation. For practitioners, understanding the social capital is crucial to users' knowledge acquisition and knowledge contribution that achieve high participation in OHCs.

Determinants of the Mobile Health Continuance Intention of Elders with Chronic Diseases: An Integrated Framework of ECM-ISC and UTAUT.

With the deepening of population aging in China, chronic diseases are a major public health concern that threatens the life and health of nationals. Mobile health or mHealth can effectively monitor chronic diseases, which holds vital significance to the alleviation of social pressure caused by aging. To patients with chronic diseases, mHealth cannot give full play to its value, only when it is used in the long term. However, there is not yet research exploring mHealth continuance intention from the perspective of elders with chronic diseases. So, this research represents the first attempt to empirically analyze mHealth continuance intention from the perspective of elders with chronic diseases. The purpose of this research is to make up the research gap of the mHealth field and to put forward theoretical and practical implications based on research results. To obtain research data, a questionnaire was conducted. A total of 926 copies were collected online and 527 copies were collected offline. The structural equation model (SEM) was used for data analysis. Research results suggest that confirmation can significantly influence satisfaction, performance expectancy and effort expectancy. Meanwhile, confirmation and performance expectancy can significantly influence satisfaction. Additionally, effort expectancy, performance expectancy, social influence and facilitating conditions can directly and significantly influence continuance intention. Among them, performance expectancy can directly influence continuance intention in the most significant way. This research provides solid evidence for the validity of the integrated model of ECM-ISC and UTAUT in the mHealth field, which can be a theoretical basis for mHealth operators' product R&D.

Well entrapped platinum-iron nanoparticles on three-dimensional nitrogen-doped ordered mesoporous carbon as highly efficient and durable catalyst for oxygen reduction and zinc-air battery.

The high-performance and durable oxygen reduction reaction (ORR) catalyst on air cathode is a key component in assembly of Zn-air batteries. Herein, three-dimensional N-doped ordered mesoporous carbon (3D N-OMC) was first prepared with silica as a template via pyrolysis with assistance of dicyandiamide as a N-doping agent, combined by full adsorption of platinum (II) acetylacetonate (Pt(acac)2) and iron (II) phthalocyanine (FePc) via π-π interactions. After further pyrolysis of the resulting mixture, many PtFe nanoparticles were efficiently incorporated in 3D N-OMC (termed as PtFe@3D N-OMC for simplicity). Control experiments were certificated the important role of the pyrolysis temperature played in this synthesis. The resultant composite synergistically combines advantages of hierarchically accessible surfaces, highly open structure, and well-dispersed PtFe particles, which endow the PtFe@3D N-OMC with onset and half-wave potentials of 0.98 and 0.86 V in alkaline media, respectively, showing appealing catalytic activity for the ORR. Most significantly, the PtFe@3D N-OMC based Zn-air battery has a high power density of 80.57 mW cm-2 and long-term durability (220 h, 660 cycles). This work opens a new avenue for design of high-efficiency and durable ORR electrocatalysts in energy conversion and storage systems.

Small lesion depiction and quantification accuracy of oncological 18F-FDG PET/CT with small voxel and Bayesian penalized likelihood reconstruction.

BACKGROUND: To investigate the influence of small voxel Bayesian penalized likelihood (SVB) reconstruction on small lesion detection compared to ordered subset expectation maximization (OSEM) reconstruction using a clinical trials network (CTN) chest phantom and the patients with 18F-FDG-avid small lung tumors, and determine the optimal penalty factor for the lesion depiction and quantification. METHODS: The CTN phantom was filled with 18F solution with a sphere-to-background ratio of 3.81:1. Twenty-four patients with 18F-FDG-avid lung lesions (diameter < 2 cm) were enrolled. Six groups of PET images were reconstructed: routine voxel OSEM (RVOSEM), small voxel OSEM (SVOSEM), and SVB reconstructions with four penalty factors: 0.6, 0.8, 0.9, and 1.0 (SVB0.6, SVB0.8, SVB0.9, and SVB1.0). The routine and small voxel sizes are 4 × 4 × 4 and 2 × 2 × 2 mm3. The recovery coefficient (RC) was calculated by dividing the measured activity by the injected activity of the hot spheres in the phantom study. The SUVmax, target-to-liver ratio (TLR), contrast-to-noise ratio (CNR), the volume of the lesions, and the image noise of the liver were measured and calculated in the patient study. Visual image quality of the patient image was scored by two radiologists using a 5-point scale. RESULTS: In the phantom study, SVB0.6, SVB0.8, and SVB0.9 achieved higher RCs than SVOSEM. The RC was higher in SVOSEM than RVOSEM and SVB1.0. In the patient study, the SUVmax, TLR, and visual image quality scores of SVB0.6 to SVB0.9 were higher than those of RVOSEM, while the image noise of SVB0.8 to SVB1.0 was equivalent to or lower than that of RVOSEM. All SVB groups had higher CNRs than RVOSEM, but there was no difference between RVOSEM and SVOSEM. The lesion volumes derived from SVB0.6 to SVB0.9 were accurate, but over-estimated by RVOSEM, SVOSEM, and SVB1.0, using the CT measurement as the standard reference. CONCLUSIONS: The SVB reconstruction improved lesion contrast, TLR, CNR, and volumetric quantification accuracy for small lesions compared to RVOSEM reconstruction without image noise degradation or the need of longer emission time. A penalty factor of 0.8-0.9 was optimal for SVB reconstruction for the small tumor detection with 18F-FDG PET/CT.

Diagnostic accuracy of dual-source CT coronary angiography with prospective ECG-triggering on different heart rate patients.

OBJECTIVE: To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR). METHODS: 103 patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR (≤60 bpm, n = 34); medium HR (60 < HR ≤ 70 bpm, n = 36) and high HR (>70 bpm, n = 33). The sensitivity and specificity of DSCT in detecting ≥50% stenosis were compared among subgroups where ICA was the gold standard. Image quality was scored using a 4-point scale. RESULTS: A total of 1,580 (95.9%) coronary artery segments were evaluable. Sensitivity and specificity were 82.8% and 98.4%, 88.3% and 98.7%, and 80.3% and 98.6% for different subgroups (all p > 0.05). The overall area under the curve of the receiver-operating characteristic analysis was 0.94. The image quality scores were 3.1 ± 0.3, 3.1 ± 0.3 and 3.0 ± 0.4 for subgroups (p > 0.05). The overall average effective radiation dose was 3.60 ± 1.60 mSv. CONCLUSION: DSCT coronary angiography with prospective ECG-triggering could be just as accurate in patients with medium to high HR compared to those with low HR.

An Empirical Study on the Dairy Product Consumers' Intention to Adopt the Food Traceability's Technology: Push-Pull-Mooring Model Integrated by D&M ISS Model and TPB With ITM.

Against the backdrop of frequent food safety problems, the importance of establishing food traceability systems has become increasingly important and urgent to address the contradiction between consumer information on safe food choices and the proliferation of problematic foods. The purpose of this study is to empirically study the influencing factors of Chinese consumers on the food traceability system in the food safety field (hereinafter referred to as FTS). In this study, multiple models-push factor (information system success model), pull factor (ITM theory), mooring factor (TPB), and switching intention-were integrated into the push-pulling-mooring theory (PPM) to form a conceptual PPM comprehensive model framework to study the switching intentions of two-dimensional code traceability technology for dairy products of Chinese consumers. By collecting the questionnaire survey, 305 valid questionnaires were collected from the consumers of middle- and high-end dairy products in China, and the influencing factors of thrust, pull, and mooring force were identified. The results showed that 10 of the 11 hypotheses were positive, but the impact of perceived risk on user satisfaction was negative. The important value of this study is to conduct a comprehensive empirical analysis of the key factors influencing consumer choice of traceable safe food through an integrated multi-model framework to help identify ways to establish and improve consumer willingness to use QR code traceable system products, to increase consumer confidence in the use of traceable and safe food choices.

Dual-layer spectral detector CT monoenergetic reconstruction improves image quality of non-contrast cerebral CT as compared with conventional single energy CT.

PURPOSE: To investigate and compare image quality of monoenergetic reconstructions from spectral NCCT to conventional 120 kVp images acquired at a similar dose. MATERIALS AND METHODS: Patients undergoing NCCT on a dual-layer spectral detector CT (n = 30) and a conventional CT (n = 30) were enrolled in the study. The spectral detector CT data was reconstructed at monoenergetic images from 40 to 140 keV in 5-keV increments and 65-70 keV in 1-keV increments (Group A1) and using single energy CT equivalent reconstruction (Group A2). The reference conventional 120kVp images (Group B) were acquired using a standard-of-care protocol with the same radiation dose. We evaluated the image quality of monoenergetic images and determined the optimal keV level using HU attenuation, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), artifact evaluation in posterior fossa by placing region-of-interest (ROI) and subjective image score by 2 radiologists independently using a 4-point scale (1-excellent, 4-undiagnostic). RESULTS: The SNR and subjective image score were optimal at 66-70keV, while monoenergetic 68 keV images with a higher SNR (18.48 ±â€¯1.94, 15.55 ±â€¯1.56 and 14.33 ±â€¯1.38 for Group 68keV, A2 and B respectively, p < 0.001), CNR (4.09 ±â€¯0.65, 3.43 ±â€¯0.56 and 3.52 ±â€¯0.55 for Group 68keV, A2 and B respectively, p < 0.001) and a lower noise (1.80 ±â€¯0.19, 2.11 ±â€¯0.19 and 2.25 ±â€¯0.25 for Group 68keV, A2 and B respectively, p < 0.001). CONCLUSION: Spectral NCCT monoenergetic reconstructions at 68 keV improve image quality and reduce artifact compared to conventional single energy CT without radiation dose penalty.

Iterative reconstruction to preserve image quality and diagnostic accuracy at reduced radiation dose in coronary CT angiography: an intraindividual comparison.

OBJECTIVES: This study sought to determine whether a 50%-reduced radiation dose protocol using iterative reconstruction (IR) preserves image quality and diagnostic accuracy at coronary computed tomography angiography (CTA) as compared with a routine dose protocol using traditional filtered back projection (FBP). BACKGROUND: IR techniques show promise to decrease radiation requirements at coronary CTA. No study has performed a direct head-to-head, intraindividual comparison of IR algorithms with FBP vis-à-vis diagnostic accuracy and radiation dose at coronary CTA. METHODS: Sixty consecutive subjects (45 men, 53.3 ± 9.4 years of age) prospectively underwent coronary catheter angiography (CCA) and 2 coronary CTA scans. One coronary CTA acquisition used routine radiation dose settings and was reconstructed with FBP. For another scan, the tube current-time product was reduced by 50%, and data were reconstructed with IR. Studies were blindly and randomly interpreted. Image quality, radiation dose, and diagnostic accuracy were compared using CCA as the reference standard. RESULTS: Sensitivity and specificity for diagnosing ≥50% coronary artery stenosis on a per-segment level were 88.5% and 92.1% with FBP and 84.2% and 93.4% with IR, respectively. On a per-patient level, sensitivity and specificity were 100% and 93.1% with FBP and 96.8% and 89.7% with IR, respectively (all p > 0.05). With FBP versus IR, the area under the receiver-operating characteristic curve was 0.903 (95% confidence interval [CI]: 0.881 to 0.922) and 0.888 (95% CI: 0.864 to 0.909) on a per-segment level, and 0.966 (95% CI: 0.883 to 0.996) and 0.932 (95% CI: 0.836 to 0.981) on a per-patient level, respectively (p = 0.290 and 0.330). Compared with FBP, the iterative series showed no significant (p > 0.05) differences in image quality analyses. Median dose-length product was 52% lower for the IR protocol compared with the FBP protocol (109.00 [interquartile range: 82.00 to 172.50] mGy·cm vs. 52.00 [interquartile range: 39.00 to 84.00] mGy·cm, p < 0.001). CONCLUSIONS: Compared with a routine radiation dose FBP protocol, 50% reduced dose acquisition using IR preserves image quality and diagnostic accuracy at coronary CTA.

Image quality and dose performance of 80 kV low dose scan protocol in high-pitch spiral coronary CT angiography: feasibility study.

To investigate the image quality and dose performance of 80 kV high-pitch spiral (HPS) coronary CT angiography (CCTA). 106 patients consecutively enrolled into prospectively ECG-triggering HPS CCTA (pitch = 3.4) exam using kV/ref. mAs = 80/400, 100/370, and 120/370 when patient BMI was ≤22.5 (n = 40), between 22.5 and 27.5 (n = 53) and >27.5 kg/m² (n = 13). Image quality was assessed per-segment by two observers independently using a 4-point scale (1-excellent, 4-non-diagnosable). Image noise and signal-to-noise ratio (SNR), contrast-to-noise ratio were measured. Diagnostic image quality was obtained in 503 of 507, 687 of 693, 164 of 167 coronary segments in 80, 100, 120 kV groups without significant difference (P = 0.482). The proportions of segments with score 1-4 were not significantly different among three kV groups (all P > 0.05). Image noise were significantly higher in 80 kV group than 100 and 120 groups (P < 0.001), while SNR was not (P = 0.097). The effective dose of 80 kV group (0.36 ± 0.03 mSv) was significantly lower than that of 100 kV group (0.86 ± 0.08 mSv) and 120 kV group (1.77 ± 0.18 mSv). The mean ± SD of HR in all patients was 54.8 ± 5.1 bpm. 80 kV HPS CCTA is feasible for patient with BMI ≤ 22.5 kg/m² which can save 58% dose than 100 kV group, while maintain diagnosable image quality.

Quantitative analysis of pulmonary artery and pulmonary collaterals in preoperative patients with pulmonary artery atresia using dual-source computed tomography.

OBJECTIVE: To evaluate the value of dual-source computed tomography (DSCT) in quantitatively measuring pulmonary arteries and major aortopulmonary collateral vessels in comparison with conventional angiographic (CA) on preoperative patients with pulmonary artery atresia and ventricular septal defect (PAA-VSD). MATERIALS AND METHODS: Twenty PAA-VSD patients who had complete imaging data of DSCT, CA and echocardiography (ECHO) studies were retrospectively analyzed. Using final clinical diagnosis as the standard, results of DSCT, CA and ECHO on the detection of cardiac malformations, measurement of diameters of pulmonary artery and collateral vessel, as well as the values of McGoon ratio, pulmonary arterial index (PAI) and total neopulmonary arterial index (TNPAI) were derived and compared. RESULTS: In 20 patients, 51 of 54 (94.4%) cardiac malformations were visualized by DSCT, whereas 42 (77.8%) by ECHO (p = 0.027). Fourteen cases with aortopulmonary collateral vessels were all (100%) detected by DSCT, whereas 5 cases (35.7%) by ECHO (p = 0.001), and 13 cases (92.9%) by CA (p = 0.995). Sixteen cases with confluence of native pulmonary arteries were diagnosed by DSCT, whereas 10 cases by CA (p = 0.024). Measurement of the diameters of pulmonary arteries, collateral vessels, and descending aorta at the level of diaphragm were correlated well between DSCT and CA (r = 0.95-0.99). McGoon ratio (DSCT=1.18 ± 0.60, CA = 1.23 ± 0.64), PAI (DSCT=130.96 ± 99.38 mm²/m², CA = 140.91 ± 107.87 mm²/m²) and TNPAI (DSCT=160.31 ± 125.62 mm²/m², CA = 169.14 ± 122.81 mm²/m²) were calculated respectively, without significant differences between DSCT and CA by paired t-tests (all p > 0.05). CONCLUSION: DSCT was efficient for evaluating and measuring native pulmonary artery and aortopulmonary collateral vessels prior to surgical procedures in PAA-VSD patients. Combined with echocardiography, DSCT showed potential to replace CA for evaluating pulmonary artery atresia noninvasively.

Comparison of diagnostic accuracy and radiation dose between prospective triggering and retrospective gated coronary angiography by dual-source computed tomography.

The purpose of this study was to evaluate and compare the diagnostic accuracy and radiation dose of dual-source computed tomographic (DSCT) coronary angiography for assessment of coronary artery disease using prospective electrocardiographic triggering and retrospective electrocardiographically (ECG) gated spiral scans. One hundred sixteen patients who had undergone dual-source computed tomography and conventional coronary angiography were enrolled in this study. Fifty-four patients were scanned using retrospective ECG-gated protocols (group 1) and 62 patients using prospective ECG-triggered protocols (group 2). Diagnostic accuracy, image quality, and effective dose were compared between groups 1 and 2. Conventional coronary angiography was used as the reference standard. In total 1,709 (98.2%) coronary segments in the 116 patients were assessable with adequate image quality. Sensitivities and specificities of diagnosing coronary heart disease (≥50% stenosis) in a patient-based analysis of DSCT data were 93.3% and 88.9% in group 1 and 96.4% and 85.7% in group 2, respectively (p=0.973 and 0.761). In vessel-based analysis, sensitivities and specificities were 77.4% and 94.1% in group 1 and 79.6% and 92.3% in group 2 (p=0.983 and 0.985). Overall averaged image quality scores (using 1- to 4-point scale) in groups 1 and 2 were 3.3 ± 0.4 and 3.5 ± 0.9, respectively (p=0.268). Prevalence of good (score 3.0) and excellent (score 4.0) image qualities of coronary vessels were 95.4% in group 1 and 92.4% in group 2 (p = 0.861). Effective doses were 8.82 ± 3.50 mSv (range 3.92 to 15.36) in group 1 and 2.95 ± 1.39 mSv (range 0.99 to 6.06) in group 2 (p<0.001). In conclusion, DSCT prospective ECG-triggered coronary angiography has equivalent image quality and diagnostic value compared to that of retrospective ECG-gated scans. Radiation dose was significantly decreased using prospective electrocardiographic triggering.