Changes in vascular supply pattern associated with growth of nonfunctioning pituitary adenomas

BACKGROUND: The vascular supply to nonfunctioning pituitary adenomas (NFPAs) differs compared with that of the anterior lobe of the normal pituitary gland. In this study, we aimed to identify feeding arteries and flow dynamics using 3.0 T magnetic resonance imaging (MRI) in NFPAs. METHODS: We divided 77 cases of NFPA into three groups according to the time-intensity curve (TIC) pattern by dynamic MRI. We also investigated the presence of feeder arteries as a flow void signal on T2-weighted imaging (T2WI). RESULTS: According to the TIC, 39 cases demonstrated an ascending pattern, 10 cases demonstrated a descending pattern, and 28 cases demonstrated a monophasic pattern. Tumor size in the ascending group was larger compared with the descending group (P = 0.0036). Flow void signals were identified in 51 of 77 cases (66.2%) on T2WI. Tumor size was larger in tumors with a flow void signal compared with those without (P < 0.0001). Flow void signals were more frequently observed in the group of ascending pattern compared with the group of monophasic and descending pattern (P = 0.032 and P = 0.003, respectively). Particularly on the caudal side, the difference between the ascending group and the monophasic and descending groups was remarkable (P = 0.0035 and P < 0.0001, respectively). CONCLUSION: We successfully evaluated the blood supply pattern by the TIC analysis and identified flow voids using 3.0 T MRI. Blood supply pattern was significantly associated with NFPA size. These results suggested that NFPA hemodynamics changes during tumor growth.