Abstract
Background
In China, ultrasound equipment is widely used, with shear wave elastography (SWE) being a popular method for assessing muscle stiffness. This study aims to establish a reference model value for perianal tissue using SWE, enhancing diagnostic capabilities for perianal conditions.
Method
Between 1st January, 2022 and 30th April, 2023, 92 patients with single-site simple anal fistula who underwent anal fistulectomy were assessed using ultrasonic SWE. Statistical methods including kernel density function, logistic regression, and ROC curve and AUC analysis were employed to establish reference values of ultrasonic SWE for perianal tissues.
Result
92 patients completed perianal normal tissue and fistula tissue detection, while 91 completed scar tissue detection. Specific critical values were identified for differentiating between perianal normal tissue and fistula tissue, with ranges varying by anatomical position. Specifically, it was 23.09 kPa (1 o'clock, 2 o'clock, 3 o'clock, 9 o'clock, 10 o'clock, and 12 o'clock positions), 38.41 kPa (5 o'clock position), 45.57 kPa (6 o'clock position), 52.99 kPa (7 o'clock position), and 41.56 kPa (11 o'clock position), respectively. The initial critical value for distinguishing scar tissue from fistula tissue was 87.28 kPa. And a range from 52.99 kPa to 87.28 kPa was deemed clinically significant for indicating fistula recurrence or residue.
Conclusion
Establishing a reference model value for perianal ultrasonic SWE enhances the diagnosis and evaluation of anal fistulae and contributes to understanding perianal tissue physiology and pathology.