Objective To investigate the diagnostic value of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters for cognitive dysfunction in first-episode stroke,thereby providing reference for the early clinical assessment of the risk of cognitive dysfunction in stroke and formulation of intervention programs.Methods A total of 122 patients with first-episode stroke were enrolled and divided into occurrence group(n=53)and non-occurrence group(n=69)according to whether they had cognitive dysfunction.Additionally,53 patients with non-cerebrovascular cognitive dysfunction were selected as control group.All patients underwent DCE-MRI examination after admission.The 3 groups and patients with different degrees of cognitive dysfunction were compared for DCE-MRI parameters,including interstitium-to-plasma rate constant(Kep),volume transfer constant(Ktrans),volume fraction of extravascular extracellular space(Ve),and volume fraction of plasma(Vp).The correlations of DCE-MRI parameters with the degree of cognitive dysfunction were analyzed,along with their diagnostic value for cognitive dysfunction and evaluation value for the risk of cognitive dysfunction after first-episode stroke.Results Both occurrence group and non-occurrence group had higher levels of Ktrans,Ve and Vp than control group,and these parameters were higher in occurrence group than non-occurrence group(P<0.05).Ktrans,Ve and Vp of patients with different degrees of cognitive dysfunction differed significantly(P<0.05),and they were increased significantly with the aggravation of cognitive dysfunction.Ktrans,Ve and Vp were all positively correlated with the degree of cognitive dysfunction (P<0.05). The AUC for the combined diagnosis using Ktrans, Ve and Vp was 0.921, significantly higher than single index (P<0.05). The risks of cognitive dysfunction in first-episode stroke patients with higher levels of Ktrans, Ve and Vp were 3.077, 1.944 and 2.313 times of the low-level, respectively. Conclusion DCE-MRI can be used to diagnose cognitive dysfunction in first-episode stroke, providing reference for early clinical prediction of cognitive dysfunction after stroke.

Objective To assess the effects of “dual low” scanning technology in conjunction with an individualized injection protocol in enhancing the quality of abdominal contrast-enhanced CT images. Methods A total of 200 patients who underwent abdominal contrast-enhanced CT examinations at the Hainan Western Central Hospital between January 2022 and January 2024 were selected for the study. Using a random number table, participants were randomly assigned to either a control group (n = 100, sub-hypertonic contrast agent + conventional tube voltage + individualized injection protocol) or an observation group (n = 100, isotonic contrast agent + tube voltage of 100 kV + individualized injection protocol). The study compared the impact of these two methodologies on the quality of abdominal contrast-enhanced CT images. Results During the arterial phase, the CT value of the abdominal aorta was significantly higher in the observation group than that in the control group (P < 0.05), suggesting that isotonic contrast agent and low tube voltage more effectively enhanced vascular signal. During the portal vein phase, the CT value was higher and the liver parenchymal noise was lower in the observation group those in the control group (P < 0.05), further validating the advantages of the “dual low” approach during the portal venous phase. The radiation dose was significantly lower in the observation group than that in the control group (P < 0.05), indicating that the “dual low” protocol effectively reduced radiation dose while enhancing patient safety. During the arterial phase, both the abdominal aorta noise and liver parenchymal noise were lower in the observation group than those in the control group (P < 0.05), demonstrating that the “dual low” strategy effectively reduced image noise and enhanced image clarity. The image quality scores were significantly higher in the observation group than in the control group (P < 0.05), indicating that high image quality could be achieved even at reduced radiation doses and contrast agent concentrations. Conclusion The “dual low” scanning technology, combined with an individualized injection protocol, not only effectively enhances the contrast of arteries and veins, reduces image noise, and improves the overall image quality, but also decreases radiation dose and enhances patient safety. Therefore, this technology is worth being widely promoted.