Clinical implications of dynamic MRI for pituitary adenomas: clinical and histologic analysis

To determine the clinical significance of dynamic magnetic resonance imaging (MRI) for pituitary adenomas, we analyzed sequential enhancement patterns of pituitary adenomas and factors contributing to these sequential patterns. Dynamic MRI was performed in 67 patients with pituitary adenomas and compared to conventional imaging. Subjects were classified into four categories according to the sequential enhancement patterns of the adenomas. Factors supposed to correlate with enhancement pattern, such as secreting hormone, tumor size, microscopically examined vascularity and arterial involvement, and intraoperatively observed texture of the adenomas, were examined among the groups. Adenomas inclined to have late enhancement patterns were relatively small compared to those with early patterns. Tumors with very early enhancement patterns were significantly more fibrous than those with the other three patterns. The factors that contribute to sequential enhancement patterns remain unclear. None the less, scrutinizing the dynamic sequential pattern may provide useful information about the probable texture of the tumor.