Differentiation of silent corticotroph pituitary neuroendocrine tumors (PitNETs) from non-functioning PitNETs using kinetic analysis of dynamic MRI

PURPOSE: Silent corticotroph pituitary adenomas (SCAs)/pituitary neuroendocrine tumors (PitNETs) are common non-functioning pituitary adenomas (NFAs)/PitNETs with a clinically aggressive course. This study aimed to investigate the ability of time-intensity analysis of dynamic magnetic resonance imaging (MRI) for distinguishing adrenocorticotropic hormone (ACTH)-positive SCAs and ACTH-negative SCAs from other NFAs. MATERIALS AND METHODS: We retrospectively evaluated the dynamic MRI findings of patients with NFAs. The initial slope of the kinetic curve (slope(ini)) obtained by dynamic MRI for each tumor was analyzed using a modified empirical mathematical model. The maximum slope of the kinetic curve (slope(max)) was obtained by geometric calculation. RESULTS: A total of 106 patients with NFAs (11 ACTH-positive SCAs, 5 ACTH-negative SCAs, and 90 other NFAs) were evaluated. The kinetic curves of ACTH-positive SCAs had significantly lesser slope(ini) and slope(max) compared with ACTH-negative SCAs (P = 0.040 and P = 0.001, respectively) and other NFAs (P = 0.018 and P = 0.035, respectively). Conversely, the slope(ini) and slope(max) were significantly greater in ACTH-negative SCAs than in NFAs other than ACTH-negative SCAs (P = 0.033 and P = 0.044, respectively). In receiver operating characteristic analysis of ACTH-positive SCAs and other NFAs, the area under the curve (AUC) values for slope(ini) and slope(max) were 0.762 and 0748, respectively. In predicting ACTH-negative SCAs, the AUC values for slope(ini) and slope(max) were 0.784 and 0.846, respectively. CONCLUSIONS: Dynamic MRI can distinguish ACTH-positive SCAs and ACTH-negative SCAs from other NFAs.