Prediction of the consistency of pituitary adenoma: A comparative study on diffusion-weighted imaging and pathological results.

Objectives: This study aims to evaluate the role of BLADE magnetic resonance (MR) diffusion-weighted imaging (DWI) and other traditional MRI parameters to predict pituitary adenoma consistency in combination with pathological results.

Methods: Thirty-four patients with surgery and pathological diagnosis of pituitary adenomas were included in this study. All exams were performed at 3.0T with traditional MRI sequences and BLADE DWI to acquire MRI parameters, then the consistency and collagen content of pituitary adenomas were evaluated at and after surgery respectively to explore the capacity of MRI technique to predict consistency or its correlation with collagen content.

Results: According to consistency evaluated at surgery, 29 pituitary adenomas were categorised as soft while others were regarded as hard. SI ratio of pre- or post-enhanced T1-weighted images, T2-weighted images or ADC values exhibited no significant relationship with adenoma consistency. To some extent, the ADC ratio had diagnostic value to predict hard consistency for ADC<1.077, while the AUC was 0.7724 for the ROC curve. H.E. staining and Masson staining were used to assess collagen content qualitatively and quantitatively. Adenoma consistency was relevant to collagen content while the cut-off value for collagen content between soft and hard tumours was 15.39%; the ADC ratio exhibited close relationship with collagen content, showing a lower ADC ratio for increasing collagen content.

Conclusions: This study revealed that the ADC ratio decreased with increasing collagen content and predicted hard consistency of tumours for ADC<1.077. Correlation between ADC ratio and tumour consistency needs further exploration.