高b值弥散加权成像在缺血性中风超急性期诊断中的价值

Value of high b-value diffusion-weighted imaging in the diagnosis of hyperacute phase of acute ischemic stroke

目的探讨高b值磁共振弥散加权成像(DWI)及表观弥散系数(ADC)值在缺血性中风(AIS)超急性期(发病时间<6 h)诊断中的应用价值,以期为临床治疗提供参考。方法选取2020年6月—2023年2月在重庆市北碚区中医院经临床确诊和治疗痊愈或好转的AIS超急性期患者34例为研究对象。34例患者均完成高b值(b值=2000 s/mm^(2))、常规b值(b值=1000 s/mm^(2))DWI扫描,将2组DWI图像分为高b值组和常规b值组,分析2组图像的DWI影像特点,并对ADC图进行定量分析。结果高、常规b值组显示病灶分别为98、74个。所研究病例T1WI均呈等或稍低信号、T2WI和T2-Flair呈等或稍高信号,无特异性;高b值组病灶DWI呈中等、明显高信号,常规b值组病灶DWI呈轻度、中等高信号,且高b值组病灶边界显示更清楚。高、常规b值组图像的ADC值比较,病变区ADC值在高b值组更低,2组差异有统计学意义(P<0.05),健侧对称区ADC值也在高b值组更低,2组差异也具有统计学意义(P<0.05);同一b值下的ADC值比较,病变区与健侧对称区ADC值差异均具有统计学意义(P<0.05)。高b值组图像敏感度为100.0%,特异度为82.4%;常规b值组,敏感度为100.0%,特异度为76.5%。高b值组图像SNR、CNR均高于常规b值组,差异均有统计学意义(P<0.05)。结论在临床工作中,采用高b值DWI扫描可以提高AIS超急性期病灶的检出率,并且能使病灶影像质量达到更佳的效果。所以,高b值DWI对超急性期AIS的诊断价值优于常规b值DWI,可能值得临床运用推广。

Objective To explore the application value of high b-value diffusion-weighted imaging(DWI)and apparent diffu-sion coefficient(ADC)in the diagnosis of hyperacute phase of acute ischemic stroke(AIS),and provide a reference for clini-cal treatment.Methods A total of 34 patients with AIS in the hyperacute phase(onset time<6 hours)who were clinically diagnosed and treated with recovery or improvement from June 2020 to February 2023 at the Beibei Hospital of Traditional Chinese Medicine were selected as the study participants.All 34 patients underwent high b-value(b-value=2000 s/mm^(2))and conventional b-value(b-value=1000 s/mm^(2))DWI scans.The DWI images were divided into a high b-value group and a conventional b-value group,and the DWI imaging features of the two groups were analyzed.Quantitative analysis was per-formed on the ADC maps.Results The number of lesions detected in the high b-value and conventional b-value groups was 98 and 74,respectively.T1-weighted images showed equal or slightly low signal,and T2-weighted images and T2-Flair im-ages showed equal or slightly high signal,with no specificity.The DWI images of the lesions in the high b-value group showed a moderate to high signal,while those in the conventional b-value group showed a mild to moderate high signal.Mo-reover,the lesion boundaries were clearer in the high b-value group.The comparison of ADC values between the high b-val-ue and conventional b-value groups showed that the ADC values in the lesion area were significantly lower in the high b-value group(P<0.05).The ADC values in the symmetrical area of the unaffected side were also significantly lower in the high b-value group(P<0.05).The comparison of ADC values at the same b-value showed statistically significant differences in ADC values between the lesion area and the symmetrical area of the unaffected side in both groups(P<0.05).The sensitiv-ity of the high b-value group was 100.0%,while the specificity was 82.4%.In the conventional b-value group,the sensitiv-ity was 100.0%,while the specificity was 76.5%.The signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were significantly higher in the high b-value group than in the conventional b-value group(P<0.05).Conclusion In clinical practice,the use of high b-value DWI scanning can raise the detection rate of AIS lesions in the hyperacute phase and pro-mote the quality of lesion imaging.Therefore,high b-value DWI has a higher diagnostic value for hyperacute phase AIS than conventional b-value DWI,which may hold promise for a wider clinical application.