Pituitary adenoma: correlation of half-dose gadolinium-enhanced MR imaging with surgical findings in 26 patients

Article Abstract:

Magnetic resonance (MR) imaging is a diagnostic imaging technique that uses the varying magnetic properties of cells and tissues to produce images of them. Contrast agents are often administered to patients who are undergoing MR imaging to obtain images with better differentiation of the organs and tissues being examined. MR imaging is used to detect tumors in the pituitary gland with varying degrees of success. When contrast agents are used at normal levels during MR imaging, the tumors and the surrounding normal tissue are often equally enhanced by the agents and the resulting images are nondiagnostic. This study examined if using reduced amounts of the contrast agent, with a resulting decrease in enhancement, would result in better detection of pituitary tumors on MR images. The MR imaging results of 26 patients who underwent surgery for suspected pituitary tumors were compared with surgical results. All 26 patients underwent MR imaging with a half dose of the contrast agent gadopentetate dimeglumine (gadolinium). Surgical results revealed that 11 patients had microadenoma tumors in the pituitary gland, 12 had macroadenoma tumors in the pituitary gland, and 1 had pituitary tissue necrosis (death). MR results prior to surgery detected 10 of the 11 microadenomas and closely predicted the sizes of the tumors. All 12 macroadenomas were detected by MR imaging. Contrast enhancement was essential for diagnosis in five cases of microadenoma and four cases of macroadenoma; it was helpful in two cases of microadenoma and three cases of macroadenoma; contrast was unnecessary in two cases of microadenoma and in five cases of macroadenoma. The effectiveness of the half-dose contrast enhancement was comparable to full-dose enhancement. Even if half-dose enhancement is only equally as effective as full-dose enhancement, it is an important finding because contrast agents are very expensive and smaller dosages would result in considerable cost savings. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods, Usage, Gadolinium, Paramagnetic contrast media

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Pituitary microadenomas: a PET study

Article Abstract:

The pituitary gland is sometimes afflicted with microadenomas, small benign tumors found in epithelial tissue. Noninvasive assessment of these tumors is required. Presently, computed tomography (CT) and magnetic resonance (MR) imaging are the two diagnostic techniques used for this purpose. Positron emission tomography (PET) is currently used to measure metabolic and physiological functions in the brain. Some have suggested that it may be of use in tumor detection. PET uses a computer to form images; the computer uses data transmitted from radioactive materials that have been incorporated into the brain's biochemistry. Fluorine-18-2-flurodeoxyglucose (FDG) is one of the materials used in PET. By detecting the uptake of FDG, PET may reveal the presence of a tumor. This study assessed results of PET-FDG from 20 patients with pituitary microadenomas, and compared them with CT and MR results. FDG uptake was also measured in healthy volunteers. Little uptake of FDG was observed in the healthy volunteers. Of the 18 patients studied with CT, only 7 were correctly diagnosed. MR results were better; 13 patients were correctly diagnosed, 2 patients' results were inconclusive, and 4 patients' results were false-negatives (indicated normal results when tumors were actually present). PET was able to correctly diagnose 12 patients, but there were 7 false-negative results. However, PET detected tumors in four cases that MR had not detected and revealed a 2 millimeter lesion that was questionable according to MR. These results indicate that PET can be useful in diagnosing pituitary microadenomas. It is more reliable when used as a complement to MR imaging. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, PET imaging, Positron emission tomography, Contrast media, Contrast media (Chemicals), Brain tumors, Pituitary gland tumors, Pituitary tumors

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Multiple endocrine neoplasia type 1: clinical and genetic topics

Article Abstract:

The gene for multiple endocrine neoplasia type 1 (MEN1) has been discovered, leading to the possibility of screening for this condition. MEN1 is characterized by the development of many different kinds of tumors at an early age. Some are benign, some are malignant, and they affect endocrine glands as well as neuroendocrine glands in the gastrointestinal system. Skin tumors are also common. The MEN1 gene is probably a tumor suppressor gene. MEN1 gene mutations are found in most people with spontaneous MEN1 as well as hereditary MEN1.

Health aspects, Gene mutations, Gene mutation, Genetic aspects, Tumor suppressor genes, Endocrine gland cancer

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