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 explore diagnostic value of magnetic resonance apparent diffusion coefficient(ADC)combined with dynamic enhanced magnetic resonance imaging(DCE-MRI)for parotid lymphoma of parotid gland.Methods:Clinical data of 74 patients with tumors of parotid gland who admitted to Hainan Western Central Hospital from September 2021 to September 2023 were selected to carry out retrospective analysis,and they were divided into malignant tumor group(15 cases)and benign tumor group(59 cases)according to the diagnosis of surgical pathology.And then,the benign tumor group was further divided into two subgroups according to the result of surgical pathology,which included pleomorphic adenoma group(35 cases)and"parotid lymphoma of parotid gland"group(24 cases).The differences in ADC values and DCE-MRI parameters(Ve,Kep,Ktrans)were compared between malignant tumors and benign tumors,and between pleomorphic adenoma and parotid lymphoma of parotid gland.The efficacies of ADC values and DCE-MRI parameters in diagnosing malignant tumors were analyzed by means of the receiver operating characteristics(ROC)curve.Results:The ADC value,Ve value and Kep of benign tumor group were respectively(1.17±0.41)×10-3 mm2/s,(0.46±0.15)and(1.56±0.57)min,which were significantly higher than those[0.86±0.19× 103mm2/s,0.35±0.08,and 0.80±0.27 min]of malignant tumor group(t=2.841,2.733,5.004,P＜0.05),respectively.Results of binary logistic regression analysis showed that ADC,Ve and Kep were respectively influence factors on benign and malignant parotid tumors(OR=0.045,0.001,0.004,P＜0.05).ROC curve analysis showed that the AUC values of single ADC,Ve,Kep,and the combination of them were respectively 0.726,0.715,0.903 and 0.915 in diagnosing benign and malignant parotid tumors.There was not significant difference in Ktrans value between pleomorphic adenoma group and"parotid lymphoma of parotid gland"group(P＞0.05).The ADC value and Ve value of"parotid lymphoma of parotid gland"group were lower than those of pleomorphic adenoma group,while Kep value of"parotid lymphoma of parotid gland"group was higher than that of pleomorphic adenoma group,and the differences of them between two groups were significant(t=4.568,4.897,4.805,P＜0.05),respectively.Binary logistic regression analysis showed that ADC,Ve and Kep were influential factors of occurring parotid lymphoma of parotid gland(OR=0.042,0.000,13.452,P＜0.05),respectively.ROC curve analysis showed that the AUC values of single ADC,Ve and Kep,and the combined diagnosis of them were respectively 0.742,0.784,0.763 and 0.959 for parotid lymphoma of parotid gland.Conclusion:Magnetic resonance ADC value and DCE-MRI parameter have favorable value in identifying benign and malignant parotid tumors,and in identifying and diagnosing parotid lymphoma of parotid gland and pleomorphic adenoma,and the combined diagnosis has higher diagnostic value.

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.