PITUITARY MICROADENOMAS - EARLY ENHANCEMENT WITH DYNAMIC CT - IMPLICATIONS OF ARTERIAL BLOOD-SUPPLY AND POTENTIAL IMPORTANCE

In a search for early contrast medium enhancement, which can indicate the presence of direct arterial supply, a retrospective review of dyna mic computed tomographic (CT) scans was performed in 260 patients with a pituitary microadenoma smaller than 10 mm in diameter. Fifty patien ts underwent examination with dynamic CT for nonendocrinologic disease as a control group to establish the normal pattern of pituitary gland enhancement. One hundred seventy microadenomas (65.4%) displayed the usual dynamic CT pattern (ie, they did not show early enhancement befo re that of the portal system of the pituitary gland: those pituitary m icroadenomas appeared less enhanced than the normal pituitary gland du ring the entire examination). On the other hand, in 90 microadenomas ( 34.6%), early partial or complete enhancement was seen within the micr oadenoma before the normal portal enhancement of the gland. Therefore, analysis with dynamic CT yields two groups of pituitary microadenomas separable on the basis of blood supply: those with portal blood suppl y only and those with partial or predominantly direct arterial blood s upply; in theory, the second group avoids hypothalamic control.