Objective:To investigate the feasibility of the combination of free breathing with the high-threshold, short-delay technique in reducing radiation dose and the volumes of iodinated contrast agent in coronary computed tomography angiography (CCTA) for obese patients.Methods:The data of 73 obese patients with weights > 85 kg and body mass indices (BMIs) > 30 kg/m 2 who received CCTA in the Radiology Department of the Peking University Third Hospital from February 2023 to May 2024 were prospectively collected. These patients were divided into a control group (31 patients) and an experimental group (42 patients). Data were collected from the control group and experimental groups under breath-holding and free-breathing conditions, respectively. The bolus tracking thresholds, delay times, and ICA injection durations were set at 100 HU, 7 s, and 12 s for the control group and at 250 HU, 2 s, and 8 s for the experimental group, respectively. Other scanning and reconstruction parameters of both groups were consistent. The CT values and their standard deviations ( SD) of both groups were assessed and compared, with the CT values involving the lumens of the aorta (AO) root, left anterior descending (LAD), left circumflex artery (LCX), and right coronary artery (RCA). The signal-to-noise ratios (SNR) and contrast-to-noise ratio (CNR) were also calculated. The subjective assessment of image quality was performed for the 18 coronary artery segments using a 4-point scale. The effective radiation doses ( E) and the volumes of iodinated contrast agent of both groups were recorded and compared. The statistical differences in the aforementioned parameters between the groups were tested and analyzed using the analysis of variance (ANOVA), the Mann-Whitney U test, or the χ 2 test. With the results of the ICA as the gold standard, the diagnostic performance of the combination of free-breathing with the high-threshold, short-delay technique in CCTA for obese patients was assessed. Results:There was no statistically significant difference ( P > 0.05) in coronary artery images between both groups, specifically regarding the CT, SNR, and CNR values of the lumens of the AO roots, LAD, LCX, and RCA, as well as the SD values of the AO roots. Both groups received subjective scores of ≥ 3 for coronary artery images, meeting the diagnostic criteria, with no statistically significant differences ( P > 0.05). Compared with the results of the ICA, the analyses of the coronary artery segments of 23 patients from the experimental group, revealed that the accuracy, sensitivity, and specificity of CCTA in the diagnosis of > 50% stenosis were 89%, 86%, and 97%, respectively. Compared to that (45 ml) of the control group, the volume (30 ml) of iodinated contrast agent of the experimental group decreased by 33.3%, with no statistically significant difference in the effective radiation dose ( E) between both groups ( P > 0.05). Conclusions:The combination of free breathing with the high-threshold, short-delay technique can further reduce the volume of the ICA for obese patients while maintaining high CCTA image quality and diagnostic performance.

Objective:To conduct a systematic review of risk prediction models for enteral feeding intolerance in ICU patients.Methods:Relevant literature was searched in China National Knowledge Infrastructure, Wanfang Data, China Biology Medicine disc, VIP, PubMed, Web of Science, Cochrane Library, Embase, CINAHL, and Scopus, with search limits from the establishment of the databases up to July 24, 2024. Two researchers independently screened the literature and extracted data, using Prediction model Risk Of Bias ASsessment Tool to evaluate the quality of the included studies.Results:A total of 12 studies were included, which included 20 prediction models. The area under the receiver operating characteristic curve or C-index for these models ranged from 0.70 to 0.94. The overall bias risk of the 12 studies was high, with three studies having good applicability. The bias risk primarily stemmed from issues such as measurement of prediction factors, variable handling, sample size, outcome definition, and model performance evaluation.Conclusions:Existing risk prediction models for enteral feeding intolerance in ICU patients exhibit a high risk of bias. Further validation, optimization, or development of new models is required in the future.

Objective:To investigate the feasibility of the combination of free breathing with the high-threshold, short-delay technique in reducing radiation dose and the volumes of iodinated contrast agent in coronary computed tomography angiography (CCTA) for obese patients.Methods:The data of 73 obese patients with weights > 85 kg and body mass indices (BMIs) > 30 kg/m 2 who received CCTA in the Radiology Department of the Peking University Third Hospital from February 2023 to May 2024 were prospectively collected. These patients were divided into a control group (31 patients) and an experimental group (42 patients). Data were collected from the control group and experimental groups under breath-holding and free-breathing conditions, respectively. The bolus tracking thresholds, delay times, and ICA injection durations were set at 100 HU, 7 s, and 12 s for the control group and at 250 HU, 2 s, and 8 s for the experimental group, respectively. Other scanning and reconstruction parameters of both groups were consistent. The CT values and their standard deviations ( SD) of both groups were assessed and compared, with the CT values involving the lumens of the aorta (AO) root, left anterior descending (LAD), left circumflex artery (LCX), and right coronary artery (RCA). The signal-to-noise ratios (SNR) and contrast-to-noise ratio (CNR) were also calculated. The subjective assessment of image quality was performed for the 18 coronary artery segments using a 4-point scale. The effective radiation doses ( E) and the volumes of iodinated contrast agent of both groups were recorded and compared. The statistical differences in the aforementioned parameters between the groups were tested and analyzed using the analysis of variance (ANOVA), the Mann-Whitney U test, or the χ 2 test. With the results of the ICA as the gold standard, the diagnostic performance of the combination of free-breathing with the high-threshold, short-delay technique in CCTA for obese patients was assessed. Results:There was no statistically significant difference ( P > 0.05) in coronary artery images between both groups, specifically regarding the CT, SNR, and CNR values of the lumens of the AO roots, LAD, LCX, and RCA, as well as the SD values of the AO roots. Both groups received subjective scores of ≥ 3 for coronary artery images, meeting the diagnostic criteria, with no statistically significant differences ( P > 0.05). Compared with the results of the ICA, the analyses of the coronary artery segments of 23 patients from the experimental group, revealed that the accuracy, sensitivity, and specificity of CCTA in the diagnosis of > 50% stenosis were 89%, 86%, and 97%, respectively. Compared to that (45 ml) of the control group, the volume (30 ml) of iodinated contrast agent of the experimental group decreased by 33.3%, with no statistically significant difference in the effective radiation dose ( E) between both groups ( P > 0.05). Conclusions:The combination of free breathing with the high-threshold, short-delay technique can further reduce the volume of the ICA for obese patients while maintaining high CCTA image quality and diagnostic performance.

Objective:To conduct a systematic review of risk prediction models for enteral feeding intolerance in ICU patients.Methods:Relevant literature was searched in China National Knowledge Infrastructure, Wanfang Data, China Biology Medicine disc, VIP, PubMed, Web of Science, Cochrane Library, Embase, CINAHL, and Scopus, with search limits from the establishment of the databases up to July 24, 2024. Two researchers independently screened the literature and extracted data, using Prediction model Risk Of Bias ASsessment Tool to evaluate the quality of the included studies.Results:A total of 12 studies were included, which included 20 prediction models. The area under the receiver operating characteristic curve or C-index for these models ranged from 0.70 to 0.94. The overall bias risk of the 12 studies was high, with three studies having good applicability. The bias risk primarily stemmed from issues such as measurement of prediction factors, variable handling, sample size, outcome definition, and model performance evaluation.Conclusions:Existing risk prediction models for enteral feeding intolerance in ICU patients exhibit a high risk of bias. Further validation, optimization, or development of new models is required in the future.

Objective:To evaluate the feasibility of low radiation dose and low contrast dosage in coronary CT angiography (CCTA) of class I obese patients.Methods:This prospective study enrolled 57 patients (male/female, 50/7, age, 25-77 years) with body mass index (BMI) of 30-38 kg/m 2 and body weight of 85-119 kg scheduled for CCTA from August 2022 to March 2023 in our hospital. The patients were divided into two groups: control group (group A, n = 20) and low-dose group (group B, n = 37). Group A employed a standard-dose protocol: tube voltage 120 kVp and IDR 2.2 g I/s, while group B were scanned using the low-dose protocol: tube voltage 100 kVp and IDR 1.5 g I/s. Images in Group A and Group B were reconstructed with hybrid iterative reconstruction (HIR) at strength 4 and 8, respectively. Other scanning and reconstruction parameters were the same in two groups. Methods:The image quality was assessed by measuring the CT values and noise in the aortic root, left anterior descending artery and right coronary artery, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was evaluated for vessels according to the 18-segment classification system using a 4-point scale (1. poor, 4. excellent). The effective dose E and contrast dosage were compared. Statistical analysis was performed using independent samples t-test, Mann-Whitney U test or χ 2 test. Results:The BMI of groups A and B were 31.89 (30.77, 33.81) and 31.22 (30.46, 32.83) kg/m 2, respectively ( P>0.05). No statistically significant differences in CT values, noise, SNR, CNR were noticed between the two groups (all P>0.05). The mean subjective score of all coronary artery segments in the two groups were not less than 3, meeting the requirement of clinical diagnosis. There was no statistically significant difference in the overall subjective image quality between the two groups ( P>0.05). The radiation dose E in groups A and B were 7.58 and 4.49 mSv, respectively ( Z=-5.46, P<0.05). The contrast dosage in groups A and B were 66 and 45 ml, respectively. The radiation dose E and contrast dosage in group B were 41% and 32% lower than that in group A, respectively. Conclusions:For class I obese patients, it was feasible to use a low tube voltage (100 kVp) and low IDR (1.5 gI/s) protocol in CCTA. Radiation dose and contrast dosage can be reduced reasonably without compromising the CCTA image quality.