Additionally, the sonographer can make an estimation of the amount of ascitic fluid, and difficult-to-drain ascites may be drained under ultrasound guidance. An abdominal CT scan is a more accurate alternate to reveal abdominal organ structure and morphology. Classification
Ascites exists in three grades:
Grade 1: mild, only visible on ultrasound and CT
Grade 2: detectable with flank bulging and shifting dullness
Grade 3: directly visible, confirmed with the fluid wave/thrill test

Pathophysiology
Ascitic fluid can accumulate as a transudate or an exudate. Amounts of up to 35 liters are possible. Roughly, transudates are a result of increased pressure in the hepatic portal vein (>8 mmHg, usually around 20 mmHg (e.g., due to cirrhosis), while exudates are actively secreted fluid due to inflammation or malignancy. As a result, exudates are high in protein and lactate dehydrogenase and have a low pH (<7.30), a low glucose level, and more white blood cells. Transudates have low protein (<30 g/L), low LDH, high pH, normal glucose, and fewer than 1 white cell per 1000 mm3. Clinically, the most useful measure is the difference between ascitic and serum albumin concentrations. A difference of less than 1 g/dl (10 g/L) implies an exudate.Portal hypertension plays an important role in the production of ascites by raising capillary hydrostatic pressure within the splanchnic bed. Regardless of the cause, sequestration of fluid within the abdomen leads to additional fluid retention by the kidneys due to stimulatory effect on blood pressure hormones, notably aldosterone.
Clinical use
DES was first marketed for medical use in 1939. It was approved by the United States Food and Drug Administration (FDA) on September 19, 1941, in tablets up to 5 mg for four indications: gonorrheal vaginitis, atrophic vaginitis, menopausal symptoms, and postpartum lactation suppression to prevent breast engorgement. The gonorrheal vaginitis indication was dropped when the antibiotic penicillin became available. From its very inception, the drug was highly controversial.In 1941, Charles Huggins and Clarence Hodges at the University of Chicago found estradiol benzoate and DES to be the first effective drugs for the treatment of metastatic prostate cancer. DES was the first cancer drug.Orchiectomy or DES or both were the standard initial treatment for symptomatic advanced prostate cancer for over 40 years, until the GnRH agonist leuprorelin was found to have efficacy similar to DES without estrogenic effects and was approved in 1985.From the 1940s until the late 1980s, DES was FDA-approved as estrogen replacement therapy for estrogen deficiency states such as ovarian dysgenesis, premature ovarian failure, and after oophorectomy. In the 1940s, DES was used off-label to prevent adverse pregnancy outcomes in women with a history of miscarriage. On July 1, 1947, the FDA approved the use of DES for this indication. The first such approval was granted to Bristol-Myers Squibb, allowing use of 25 mg (and later 100 mg) tablets of DES during pregnancy. Approvals were granted to other pharmaceutical companies later in the same year.