DETECTION OF PITUITARY MICROADENOMAS - COMPARISON OF DYNAMIC KEYHOLE FAST SPIN-ECHO, UNENHANCED, AND CONVENTIONAL CONTRAST-ENHANCED MR-IMAGING

OBJECTIVE. Pituitary microadenomas may not be detected on conventional MR images. We supplemented conventional unenhanced and contrast-enhan ced MR imaging with a dynamic keyhole fast spin-echo (kFSE) method in order to compare how frequently a microadenoma could be detected with the three different methods. SUBJECTS AND METHODS. Eighteen consecutiv e patients with clinical and laboratory evidence of pituitary microade nomas had unenhanced, dynamic kFSE, and conventional contrast-enhanced MR imaging of the pituitary gland. A control group of 13 subjects wit hout pituitary disease also had dynamic kFSE MR imaging. Hard copies o f all the studies were obtained in an identical fashion, and then the MR images of the patients and control subjects were randomly mixed. Th e studies were reviewed by a neuroradiologist who had no knowledge of the clinical status of the subjects. The presence or absence of any pi tuitary focal hypointensity consistent with the appearance of a microa denoma was noted. RESULTS. A pituitary lesion consistent in appearance with a microadenoma was detected on dynamic kFSE images in 13 of the 18 patients, on unenhanced images in nine patients, and on conventiona l contrast-enhanced images in 10 patients. In four patients, a microad enoma was detected on dynamic kFSE images only. Dynamic kFSE images sh owed a lesion in four of the 13 control subjects. CONCLUSION. Dynamic kFSE MR imaging is a useful supplemental sequence in patients undergoi ng MR imaging because of pituitary endocrinopathy. It may show lesions that would otherwise escape detection.