The beads-on-a-string sign is used to refer to the classic morphologic changes in the Fallopian tubes as a result of chronic salpingitis.
The "string" alludes to the notably thin salpingeal wall, while the hyperechoic mural nodules constitute the "beads" 1.
Chronic inflammation and fibrosis of the involved salpinx results in fimbrial or ostial occlusion; lack of outflow results in fluid accumulation, leading to tubal distension and progressive mural distension and effacement. The endosalpingeal folds are also involved, flattening and eventually fibrosing. These fibrotic, irregular structures appear as 2–3 mm, echogenic mural nodules protruding into the tubal lumen 1.
The ultrasound finding of a distended, thin-walled tubular salpinx with hyperechoic mural nodules protruding at irregular intervals into a fluid-filled lumen is highly suggestive of chronic salpingitis 2.
- 1. Timor-Tritsch IE, Lerner JP, Monteagudo A, Murphy KE, Heller DS. Transvaginal sonographic markers of tubal inflammatory disease. (1998) Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 12 (1): 56-66. doi:10.1046/j.1469-0705.1998.12010056.x - Pubmed
- 2. Coremans L, de Clerck F. Fitz-Hugh-Curtis syndrome associated with tuberculous salpingitis and peritonitis: a case presentation and review of literature. (2018) BMC gastroenterology. 18 (1): 42. doi:10.1186/s12876-018-0768-0 - Pubmed