Petrosal sinus sampling with and without corticotropin-releasing hormone for the differential diagnosis of Cushing's syndrome

Article Abstract:

Cushing's syndrome is a condition characterized by excessive levels of the hormone cortisol. The syndrome has many causes, one of which is a tumor (microadenoma) of the pituitary gland that secretes adrenocorticotropin, the hormone that stimulates the adrenal gland to produce cortisol. Patients with microademonas of this sort are said to have Cushing's disease. To evaluate the effectiveness of one method of diagnosing Cushing's disease, a study was carried out of 278 patients with this disorder. Investigators sampled blood from the inferior petrosal sinus (IPS), the contents of which include adrenocorticotropin, and compared these results with those obtained from sampling peripheral blood (P; distant from the brain). (The IPS is one of the many blood-filled venous cavities in the brain.) This comparison, as well as comparisons of measurements from the petrosal sinuses on both sides of the brain, could show whether an adrenocorticotropin-producing microadenoma was present in the pituitary on one side. In 262 cases, corticotropin releasing hormone (CRH), which stimulates the pituitary to secrete adrenocorticotropin, was also sampled. A total of 215 patients were found to have Cushing's disease: of these, 205 had an IPS/P ratio of 2 or greater (established as diagnostic for Cushing's disease in earlier research). All 203 patients who received CRH had IPS/P ratios of 3 or more (another criterion diagnostic level). The accuracy and reliability of the basic test and the CRH test were between 95 and 100 percent. Twenty patients had ectopic adrenocorticotropin syndrome (in which the hormone is secreted by a tumor located somewhere other than the pituitary), and 11 had disease of the adrenal gland. The standard test for Cushing's disease, the dexamethasone suppression test, failed to detect 19 percent of the patients who actually had the disease, and falsely identified 21 percent of the patients with ectopic adrenocorticotropin secretion as having Cushing's disease. A discussion is presented of the safety and recommended use of petrosal sinus sampling. (Consumer Summary produced by Reliance Medical Information, Inc.)

Measurement, Adrenocortical hormones, Corticotropin releasing hormone, Corticotropin-releasing hormone, Pituitary gland tumors, Pituitary tumors, Adrenal gland diseases

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Cushing syndrome due to primary pigmented nodular adrenocortical disease: Findings at CT and MR imaging

Article Abstract:

A rare cause of Cushing syndrome, a disease of the adrenal cortex that disrupts the normal secretion of adrenalin, is primary pigmented nodular adrenocortical disease (PPNAD). PPNAD occurs in infants, young chidden, and young adults. The symptoms of PPNAD are often mild, and a long interval between the onset of symptoms and the diagnosis is common. Osteoporosis may be an unusually severe component of the syndrome associated with PPNAD. Upon examination, the adrenal glands in persons suffering from PPNAD, range from small to slightly enlarged and contain multiple dark brown or black nodules that vary from microscopic to six millimeters in diameter. The cause of the disease is not known, although PPNAD may be hereditary. Because of the rarity of the disease, PPNAD imaging studies have been reported in only a few patients. The use of computed tomography (CT) scanning to observe the adrenal gland is important, since adrenal glands in these patients show nodule growth. Magnetic resonance (MR) images of the adrenal glands were also used by the researchers to look for the presence of nodules associated with PPNAD. It was concluded that the adrenal glands had normal dimensions, but a knobby or irregular contour in young patients who have Cushing syndrome should suggest the diagnosis of PPNAD.

Causes of, Osteoporosis, Adrenal glands

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Gastrinomas: comparison of MR imaging with CT, angiography, and US

Article Abstract:

Magnetic resonance (MR) imaging was tested preoperatively to identify gastrinoma in 24 patients with Zollinger-Ellison Syndrome (ZES). ZES involves the growth and spread of gastrin hypersecreting tumors of the pancreas. ZES patients suffer from gastric acid damage to the liver, gallbladder, small intestines, stomach, and pancreas. The study compared MR imaging of ZES gastrinomas to images obtained using computed tomography (CT) scanning, ultrasound (US), and angiography (blood vessel imaging by x-ray). The study's conclusion showed MR imaging to be as effective as US, while CT was the best technique, overall, for evaluating ZES gastrinomas. MR failed to detect small gastrinomas lying outside the liver (extrahepatic), while CT and angiography were able to detect these small lesions. The study suggests, however, that MR may be superior to CT in examination of patients with spreading gastrinomas (metastasizing). Frequent CT or angiographic scanning to assess patient response to therapy in metastatic gastrinoma lesions (abnormal tissue growth) may be difficult. Frequent MR exams may be particularly useful for showing the outline and size of liver gastrinomas. The results of this study show that MR imaging is generally not useful in the first attempts at locating gastrinomas in a patient.

Comparative analysis, Magnetic resonance imaging, Angiography, Medical imaging equipment, Diagnosis, Ultrasonic, Diagnostic ultrasonography, Zollinger-Ellison syndrome

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