Abstract：Objective：To systematically evaluate the diagnostic efficacy of transperineal ultrasound （TPUS），transrectal endoscopic ultrasound （TRUS），three-dimensional ultrasound （3D-TRUS），and their combined schemes for Crohn's disease（CD）complicated with anal fistula （PF），and to provide evidence-based guidance for the selection of imaging pathways in clinical practice. Methods：Through computer retrieval of CNKI，Wanfang Data，and VIP databases，studieson the assessment of Crohn's disease complicated with anal fistula using ultrasound methods （such as transperineal ultrasound，transrectal ultrasound，three-dimensional ultrasound，etc.）published from the establishment of the database to March 2025 were collected. Two researchers independently screened the literature，extracted data，and evaluated the methodological quality using the QUADAS-2 tool. Using Stata 18.0 software，meta-analysis was conducted to combine the effect sizes of diagnostic odds ratio （DOR），sensitivity，specificity，and their 95% confidence intervals. Results： A total of 9 studies were included，involving 1126 patients and 1532 fistula lesions. The meta-analysis results showed that the combined diagnostic efficacy of transperineal ultrasound and transrectal ultrasound was the highest，with a combined sensitivity of 0.91（95% CI：0.85-0.95），specificity of 0.89（95% CI：0.82-0.94），and DOR of 85.42（95% CI：42.17-173.05）. The sensitivity of simple transrectal ultrasound was 0.87（95% CI：0.80-0.92），and the specificity was 0.83 （95% CI：0.76-0.89）. Three-dimensional ultrasound had advantages in the display of fistula tract and internal orifice. There was moderate heterogeneity（I2= 67.3%）among the studies，and subgroup analysis suggested that heterogeneity was related to ultrasound technique type，reference standard，and patient disease activity. Publication bias test did not show significant bias. Conclusion：Current evidence indicates that transperineal ultrasound combined with transrectal ultrasound has high accuracy in the diagnosis of Crohn's disease complicated with anal fistula，especially for the assessment of complex fistulas. Three-dimensional ultrasound can be used as a supplementary method to improve the display of anatomical details. It is recommended to combine clinical to comprehensively select ultrasound examination strategies to optimize the diagnosis and treatment process.
Duan et al. (2025) studied this question.