Abstract：
OBJECTIVE: Detection of lower gastrointestinal bleeding (LGIB) through noninvasive modalities is very important in the successful management of LGIB. RBC scintigraphy and CT have a role in the detection of LGIB and guiding the management of patient by localization of the bleeding site. However, only a small number of studies have evaluated the role of RBC scintigraphy and CT in the diagnosis of LGIB. This systematic review was conducted to evaluate the diagnostic performance of RBC scintigraphy and CT in the detection of LGIB in patients with clinical or biochemical findings suspicious of LGIB.
METHODS: This systematic review followed PRISMA guidelines. Searches in PubMed, Scopus, and Embase were conducted using relevant keywords, and articles published through 30 April 2022, were included. Using endoscopy or surgical outcomes as the reference standard, the numbers of true and false positives and true and false negatives were extracted. Pooled estimates of diagnostic test accuracy - including sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and summary ROC (SROC) curve - were generated using bivariate random-effects meta-analysis.
RESULTS: Three studies comprising 171 patients were included in the systematic review and meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for the detection of LGIB using RBC scintigraphy were 0.787 (95% CI, 0.643-0.893), 0.289 (95% CI, 0.164-0.443), 1.214 (95% CI, 0.923-1.597) and 0.576 (95% CI, 0.296-1.121) respectively. The area under the SROC curve was 0.73. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for the detection of LGIB using CT were 0.931 (95% CI, 0.772-0.992), 0.870 (95% CI, 0.737-0.951), 6.085 (95% CI, 0.840-44.097), 0.126 (95% CI, 0.006-2.509) respectively. The area under the SROC curve was 0.095.
CONCLUSIONS: RBC scintigraphy has overall good sensitivity and CTA has excellent sensitivity specificity, positive and negative likelihood ratio in the detection of LGIB in patients with clinical or biochemical findings suspicious for LGIB.CTA along with RBC scintigraphy can be used algorithmically to rule out patients who do not have a localization for the site of LGIB thereby helping these patients to avoid invasive procedures like endoscopy or surgical explorations.
METHODS: This systematic review followed PRISMA guidelines. Searches in PubMed, Scopus, and Embase were conducted using relevant keywords, and articles published through 30 April 2022, were included. Using endoscopy or surgical outcomes as the reference standard, the numbers of true and false positives and true and false negatives were extracted. Pooled estimates of diagnostic test accuracy - including sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and summary ROC (SROC) curve - were generated using bivariate random-effects meta-analysis.
RESULTS: Three studies comprising 171 patients were included in the systematic review and meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for the detection of LGIB using RBC scintigraphy were 0.787 (95% CI, 0.643-0.893), 0.289 (95% CI, 0.164-0.443), 1.214 (95% CI, 0.923-1.597) and 0.576 (95% CI, 0.296-1.121) respectively. The area under the SROC curve was 0.73. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for the detection of LGIB using CT were 0.931 (95% CI, 0.772-0.992), 0.870 (95% CI, 0.737-0.951), 6.085 (95% CI, 0.840-44.097), 0.126 (95% CI, 0.006-2.509) respectively. The area under the SROC curve was 0.095.
CONCLUSIONS: RBC scintigraphy has overall good sensitivity and CTA has excellent sensitivity specificity, positive and negative likelihood ratio in the detection of LGIB in patients with clinical or biochemical findings suspicious for LGIB.CTA along with RBC scintigraphy can be used algorithmically to rule out patients who do not have a localization for the site of LGIB thereby helping these patients to avoid invasive procedures like endoscopy or surgical explorations.
摘要：
目的：通过无创方式检测下消化道出血（LGIB）对于LGIB的成功治疗非常重要。红细胞闪烁显像和CT在检测LGIB和通过定位出血部位指导患者管理方面具有作用。然而,只有少数研究评估了RBC闪烁显像和CT在LGIB诊断中的作用.进行了这项系统评价，以评估RBC闪烁显像和CT在临床或生化发现可疑LGIB的患者中检测LGIB的诊断性能。
方法：本系统综述遵循PRISMA指南。在PubMed中搜索,Scopus,Embase是使用相关关键词进行的，和截至2022年4月30日发表的文章都包括在内。使用内窥镜或手术结果作为参考标准，提取真假阳性和真假阴性的数量。诊断测试准确性的汇总估计-包括灵敏度，特异性，正似然比，负似然比，和总结ROC（SROC）曲线-使用双变量随机效应荟萃分析生成。
结果：包括171例患者的三项研究纳入了系统评价和荟萃分析。汇集的敏感性，特异性，正似然比，使用RBC闪烁显像检测LGIB的阴性似然比为0.787（95％CI，0.643-0.893），0.289（95%CI，0.164-0.443），分别为1.214（95%CI，0.923-1.597）和0.576（95%CI，0.296-1.121）。SROC曲线下面积为0.73。汇集的敏感性，特异性，正似然比，使用CT检测LGIB的阴性似然比为0.931（95％CI，0.772-0.992），0.870（95%CI，0.737-0.951），6.085（95%CI，0.840-44.097），分别为0.126（95%CI，0.006-2.509）。SROC曲线下面积为0.095。
结论：红细胞闪烁显像具有良好的整体敏感性，CTA具有极好的敏感性特异性，在临床或生化结果可疑的患者中，LGIB检测的阳性和阴性似然比。可以在算法上使用CTA和RBC闪烁显像来排除对LGIB部位没有定位的患者，从而帮助这些患者避免内窥镜检查或手术探查等侵入性程序。
方法：本系统综述遵循PRISMA指南。在PubMed中搜索,Scopus,Embase是使用相关关键词进行的，和截至2022年4月30日发表的文章都包括在内。使用内窥镜或手术结果作为参考标准，提取真假阳性和真假阴性的数量。诊断测试准确性的汇总估计-包括灵敏度，特异性，正似然比，负似然比，和总结ROC（SROC）曲线-使用双变量随机效应荟萃分析生成。
结果：包括171例患者的三项研究纳入了系统评价和荟萃分析。汇集的敏感性，特异性，正似然比，使用RBC闪烁显像检测LGIB的阴性似然比为0.787（95％CI，0.643-0.893），0.289（95%CI，0.164-0.443），分别为1.214（95%CI，0.923-1.597）和0.576（95%CI，0.296-1.121）。SROC曲线下面积为0.73。汇集的敏感性，特异性，正似然比，使用CT检测LGIB的阴性似然比为0.931（95％CI，0.772-0.992），0.870（95%CI，0.737-0.951），6.085（95%CI，0.840-44.097），分别为0.126（95%CI，0.006-2.509）。SROC曲线下面积为0.095。
结论：红细胞闪烁显像具有良好的整体敏感性，CTA具有极好的敏感性特异性，在临床或生化结果可疑的患者中，LGIB检测的阳性和阴性似然比。可以在算法上使用CTA和RBC闪烁显像来排除对LGIB部位没有定位的患者，从而帮助这些患者避免内窥镜检查或手术探查等侵入性程序。
