Visual field defects in patients with pituitary adenomas.
BACKGROUND
The most common objective manifestations of pituitary adenoma are visual, including impairment of a visual field and loss of acuity. The characteristic visual field defect caused by pituitary adenomas with suprasellar extension is bitemporal hemianopsia. The present study was undertaken to determine the relationship between a visual field defect and the chiasma compression caused by pituitary adenomas.


METHODS
Between January 1994 and December 1996 within the Department of Neurosurgery at the Neurological Institute of Veterans General Hospital-Taipei, 70 patients with pituitary adenoma were selected. Their medical records and radiological films were reviewed. The qualified visual field scores were compared with the chiasma compression levels measured from computed tomography, sagittal and coronal magnetic resonance (MR) imaging. The relationships of pathological diagnosis as well as history of prior operations with visual field defect score were also evaluated.


RESULTS
patients with a pathological diagnosis of a non-functional pituitary adenoma or with a history of prior operation for the pituitary adenoma had the more severe visual field defect. The chiasma compression level, no matter measured from computed tomography, sagittal MR or coronal MR imaging, was correlated significantly with the visual field defect. The correlation coefficient was 0.764 from computed tomography, 0.688 from sagittal MR imaging, and 0.717 from coronal MR imaging. The visual field defect was present mostly when the chiasma compression exceeded a certain level when measured from computed tomography, sagittal MR and coronal MR imaging. On the other hand, variation in chiasma type had little effect on the appearance and degree of a visual field defect.


CONCLUSIONS
There was a linear correlation between a visual field defect and the chiasma compression no matter whether measured from computed tomography or from MR imaging. The visual field defect occurred mostly when the chiasma compression exceeded a certain level. A more severe visual field defect appeared in patients with nonfunctional pituitary adenoma or those with a prior operation history for the pituitary adenoma.
Huang
W C
WC
Department of Neurosurgery, Veterans General Hospital-Taipei, Taiwan, R.O.C.
Lee
L S
LS
D000236:Adenoma / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009897:Optic Chiasm; D010911:Pituitary Neoplasms / Q000503:physiopathology*; D014794:Visual Fields