CT of pituitary microadenomas.

In reading the well documented article by Davis et al. [1] in the November/December 1984 issue of AJNR, we found the title of the article to be perhaps a bit provoking and the authors' conclusion rather severe for high-resolution computed tomography (CT) of pituitary microadenomas. Two points should be emphasized: 1. The authors are correct in stating that "gland height greater than 8 mm and an abnormal diaphragma sellae configuration are neither sensitive nor specific findings of microadenoma" [1]. This is why we are convinced that demonstration of the pituitary "tuft" sign by dynamic CT is essential for microadenoma diagnosis [2] . 2. Some false-positive images, such as figure 1 A in the article by Davis et al. [1] , must be considered with caution. We have demonstrated [3] that partial-volume averaging can create a low-density image simulating an intrasellar hypodense lesion beneath a pseudobulging of the diaphragma sellae at the tuberculum sellae level , even in thin coronal sections (fig. 1 )-the "tuberculum" sign. We believe this confusing image should be considered in the presence of any hypodense image within the sella.