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Visual fields associated with chiasmal syndrome usually leads to an MRI. Contrast can delineate arterial aneurysms and will enhance most intrinsic chiasmal lesions. [1] If a mass is confirmed on MRI, an endocrine panel can help determine if a pituitary adenoma is involved.
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. [1] Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms, with an estimated prevalence rate in the general population of approximately 17%. [1] [2]
Many pituitary tumors (25%) are found to have areas of hemorrhagic infarction on MRI scans, but apoplexy is not said to exist unless it is accompanied by symptoms. [ 1 ] [ 4 ] In some instances, lumbar puncture may be required if there is a suspicion that the symptoms might be caused by other problems ( meningitis or subarachnoid hemorrhage ).
A CT or MRI of the pituitary may also show the ACTH-secreting tumor if present. However, in 40% of Cushing's disease patients MRI is unable to detect a tumor. [8] In one study of 261 patients with confirmed pituitary Cushing's disease, only 48% of pituitary lesions were identified using MRI prior to surgery.
The first MR images of a human brain were obtained in 1978 by two groups of researchers at EMI Laboratories led by Ian Robert Young and Hugh Clow. [1] In 1986, Charles L. Dumoulin and Howard R. Hart at General Electric developed MR angiography, [2] and Denis Le Bihan obtained the first images and later patented diffusion MRI. [3]
A prolactinoma is a tumor of the pituitary gland that produces the hormone prolactin.It is the most common type of functioning pituitary tumor. [1] Symptoms of prolactinoma are due to abnormally high levels of prolactin in the blood (hyperprolactinemia), or due to pressure of the tumor on surrounding brain tissue and/or the optic nerves.
A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue [1] that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence rates are childhood-onset at 5–14 years and adult-onset at 50–74 years. [2]
Empty sella syndrome is the condition when the pituitary gland shrinks or becomes flattened, filling the sella turcica with cerebrospinal fluid instead of the normal pituitary. [2] It can be discovered as part of the diagnostic workup of pituitary disorders, or as an incidental finding when imaging the brain.