WU, Jingping; CHEN, Xinyu; WU, Qiong; WEI, Na; AN, Guifang; YU, Hairong; WANG, Ning. Contrast enhanced ultrasound - a useful method for diagnosing tubal ectopic pregnancy with low level β-HCG. The Ultrasound Journal, Fidenza (PR), Italy, v. 17, n. 1, p. 33, 2025. DOI: 10.1186/s13089-025-00438-0. Disponível em: https://www.mattioli1885journals.com/index.php/theultrasoundjournal/article/view/18152. Acesso em: 23 apr. 2026.