What is the term for fluid accumulation in the abdominal cavity observed on ultrasound?

The term for fluid accumulation in the abdominal cavity observed on ultrasound is ascites. Ascites refers specifically to an abnormal collection of fluid in the peritoneal cavity, which can be caused by various underlying conditions, including liver cirrhosis, heart failure, malignancies, or infections. When performing an ultrasound, areas of anechoic (dark) fluid can typically be identified, which helps in diagnosing the presence of ascites.

Understanding that ascites specifically refers to fluid in the abdominal cavity is crucial, as it distinguishes this condition from others that may involve fluid accumulation. For instance, hydronephrosis pertains to fluid buildup in the renal pelvis due to obstruction, pleural effusion describes fluid around the lungs in the pleural space, and peritonitis refers to inflammation of the peritoneum, which is not primarily defined by fluid accumulation but can result from it. Recognizing these distinctions is essential in imaging and clinical practice.