Wa. Hall et al., PITUITARY MAGNETIC-RESONANCE-IMAGING IN NORMAL HUMAN VOLUNTEERS - OCCULT ADENOMAS IN THE GENERAL-POPULATION, Annals of internal medicine, 120(10), 1994, pp. 817-820
Objective: To determine the prevalence of focal lesions of the pituita
ry gland that suggest the presence of a pituitary adenoma in asymptoma
tic persons. Design: 100 normal volunteers (70 women, 30 men; age rang
e, 18 to 60 years old) were studied by high-resolution magnetic resona
nce imaging (MRI) of the pituitary gland before and after administrati
on of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). Setting
: Occult pituitary adenomas are identified at autopsy in 3% to 27% of
unselected asymptomatic patients. The frequency of incidental pituitar
y adenomas detected by MRI in normal persons is unknown. Measurements:
The MRI scans from volunteers were randomly mixed with scans of 57 pa
tients with Cushing disease and interpreted independently by three bli
nded reviewers. Results: Seven women (10%) and three men (10%) had foc
al areas of decreased signal intensity in the pituitary gland after ad
ministration of Gd-DTPA. The lesions ranged from 3 to 6 mm in greatest
diameter and were diagnosed as pituitary adenomas by at least two of
the three reviewers. When similar lesions were detected on MRI scans i
n patients with Cushing disease, the positive predictive value for ide
ntification of an adenoma at that site was 86%. Conclusions: About 10%
of the normal adult population have pituitary abnormalities on MRI sc
ans that are compatible with the diagnosis of asymptomatic pituitary a
denomas. Most pituitary adenomas remain asymptomatic and do not requir
e treatment.