ObjectiveTo systematically review the diagnostic value of contrast transthoracic echocardiography (C-TTE) and contrast transcranial Doppler bubble test (C-TCD) for patent foramen ovale (PFO). MethodsComputer searches were conducted in PubMed, Embase, Web of Science, CNKI, WanFang Data, and CBM databases to collect studies on the diagnostic value of C-TTE and C-TCD for PFO. The retrieval time limit was from the establishment of the databases to September 30, 2024. Two ultrasound diagnostic physicians independently screened the literature, extracted data, and evaluated the risk of bias in the included studies using the QUADAS-2 and QUADAS-C tools. Then, Meta-analysis was performed using Meta-DiSc version 1.4 and R 4.4.3 software. ResultsA total of 22 studies including 2 487 patients were included. The results of the meta-analysis showed that for C-TCD in diagnosing PFO, the sensitivity (SEN), specificity (SPE), positive likelihood ratio (+LR), negative likelihood ratio (–LR), and diagnostic odds ratio (DOR) were (0.86, 95%CI 0.81 to 0.90), (0.85, 95%CI 0.78 to 0.91), (5.80, 95%CI 3.80 to 9.50), (0.17, 95%CI 0.12 to 0.23), and (34, 95%CI 18.00 to 68.00) respectively; for C - TTE in diagnosing PFO, the SEN, SPE, +LR, –LR, and DOR were (0.81, 95%CI 0.74 to 0.86), (0.92, 95%CI 0.87 to 0.96), (10.2, 95%CI 6.10 to 19.20), (0.21, 95%CI 0.15 to 0.28), and (50, 95%CI 26.00 to 101.00) respectively. The areas under the summary receiver - operating characteristic (SROC) curves (AUC) of C-TCD and C-TTE for diagnosing PFO were 0.90 and 0.85 respectively. The sensitivity difference and specificity difference between C-TCD and C-TTE were 0.05, 95%CI ?0.03 to 0.12 and ?0.07, 95%CI ?0.15 to 0.01, respectively. The DOR of C-TCD/C-TTE was 0.69, 95%CI 0.27 to 1.76. ConclusionBoth C-TCD and C-TTE have good sensitivity and specificity in the diagnosis of PFO and can be used as powerful tools for the examination of right-to-left shunt in PFO. Moreover, the diagnostic performance of the two methods is comparable. Limited by the number and quality of the included studies, the above conclusions need to be verified by more studies.
