Focal Nodular Hyperplasia: Solitary or multiple benign hepatic vascular tumors, usually occurring in women of 20-50 years of age. The nodule, poorly encapsulated, consists of a central stellate fibrous scar and normal liver elements such as HEPATOCYTES, small BILE DUCTS, and KUPFFER CELLS among the intervening fibrous septa. The pale colored central scar represents large blood vessels with hyperplastic fibromuscular layer and narrowing lumen.Adenoma, Liver Cell: A benign epithelial tumor of the LIVER.Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Liver Neoplasms: Tumors or cancer of the LIVER.Hemangioma: A vascular anomaly due to proliferation of BLOOD VESSELS that forms a tumor-like mass. The common types involve CAPILLARIES and VEINS. It can occur anywhere in the body but is most frequently noticed in the SKIN and SUBCUTANEOUS TISSUE. (from Stedman, 27th ed, 2000)Liver Diseases: Pathological processes of the LIVER.Contrast Media: Substances used to allow enhanced visualization of tissues.Sulfur Hexafluoride: Sulfur hexafluoride. An inert gas used mainly as a test gas in respiratory physiology. Other uses include its injection in vitreoretinal surgery to restore the vitreous chamber and as a tracer in monitoring the dispersion and deposition of air pollutants.Keratin-7: A type II keratin found associated with KERATIN-19 in ductal epithelia and gastrointestinal epithelia.Carcinoma, Hepatocellular: A primary malignant neoplasm of epithelial liver cells. It ranges from a well-differentiated tumor with EPITHELIAL CELLS indistinguishable from normal HEPATOCYTES to a poorly differentiated neoplasm. The cells may be uniform or markedly pleomorphic, or form GIANT CELLS. Several classification schemes have been suggested.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Contraceptives, Oral: Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally estrogen or progesterone or both.Tomography, Spiral Computed: Computed tomography where there is continuous X-ray exposure to the patient while being transported in a spiral or helical pattern through the beam of irradiation. This provides improved three-dimensional contrast and spatial resolution compared to conventional computed tomography, where data is obtained and computed from individual sequential exposures.Keratin-19: A type I keratin found associated with KERATIN-7 in ductal epithelia and gastrointestinal epithelia.Image Enhancement: Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.Gadolinium DTPA: A complex of gadolinium with a chelating agent, diethylenetriamine penta-acetic acid (DTPA see PENTETIC ACID), that is given to enhance the image in cranial and spinal MRIs. (From Martindale, The Extra Pharmacopoeia, 30th ed, p706)Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Prostatic Hyperplasia: Increase in constituent cells in the PROSTATE, leading to enlargement of the organ (hypertrophy) and adverse impact on the lower urinary tract function. This can be caused by increased rate of cell proliferation, reduced rate of cell death, or both.Hepatectomy: Excision of all or part of the liver. (Dorland, 28th ed)Angiography: Radiography of blood vessels after injection of a contrast medium.PolysaccharidesParathyroid Glands: Two pairs of small oval-shaped glands located in the front and the base of the NECK and adjacent to the two lobes of THYROID GLAND. They secrete PARATHYROID HORMONE that regulates the balance of CALCIUM; PHOSPHORUS; and MAGNESIUM in the body.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Hyperparathyroidism, Secondary: Abnormally elevated PARATHYROID HORMONE secretion as a response to HYPOCALCEMIA. It is caused by chronic KIDNEY FAILURE or other abnormalities in the controls of bone and mineral metabolism, leading to various BONE DISEASES, such as RENAL OSTEODYSTROPHY.Brunner Glands: The abundant submucosal mucous glands in the DUODENUM. These glands secrete BICARBONATE IONS; GLYCOPROTEINS; and PEPSINOGEN II.