Evaluation of Consistency of Pituitary Macroadenoma Using Diffusion-weighted Imaging in Correlation With Surgical Findings

Abstract

Objective: The consistency of pituitary macroadenomas can be a confounding factor during transnasal transsphenoidal decompression, often necessitating incomplete removal and need for a transcranial approach for complete tumor excision. Very few studies have evaluated preoperative tumor consistency in relation to imaging findings. Our objective was to determine whether conventional magnetic resonance images and diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps are predictive of the consistency of pituitary macroadenomas. Methods: A retrospective study of 31 patients who had undergone surgery for pituitary macroadenoma in our hospital. Preoperative magnetic resonance images were reviewed and regions of interest were drawn on the macroadenoma and normal white matter on DW images independently by 2 neuroradiologists. Consistency of macroadenomas was determined from the surgical records and was classified into soft, intermediate, or hard. Mean ADC values, signal intensity ratio of tumor to white matter within regions of interest on conventional and DW images, and degree of enhancement were compared with tumor consistency using analysis of variance. Results: The mean ADC values in the soft group was 0.754×10−3 mm2/s, in the intermediate group was 0.963×10−3 mm2/s, and in the hard group was 1.312×10−3 mm/s. Statistical analysis revealed a significant correlation between consistency and ADC values (P<0.004). There was no significant association between tumor consistency and signal intensity or degree of contrast enhancement. Conclusions: The findings in this study suggest that DW images with ADC maps are useful for preoperative prediction of consistency of pituitary macroadenomas.