In addition to gathering information about patients' general and health characteristics, the researchers did blood tests of patients' liver function both before they began the intravenous feeding and again 3, 6, and 12 months later. After 12 months, they did blood tests and ultrasound studies (πctures taken by using sound waves) of the liver yearly or if complications occurred. If the results suggested liver problems, the patients had a liver biopsy. A liver biopsy involves taking a small sample of liver tissue through a needle inserted into the abdomen. Experts then examine the tissue under a microscope. The researchers also collected information on the nutritional content of each patient's intravenous feeding.