PIT-000790 (sō″nō-hĭs″tĕ-rŏg′ră-fē, sŏ″) [L. sonus, sound + ″] Instillation of 10 to 20 ml of saline into the uterus to enhance ultrasonic imaging and help determine the cause of abnormal uterine bleeding, female infertility, or to identify uterine masses.