This study aimed to investigate the role of diffusion-weighted imaging (DWI) in predicting tumor consistency, extent of surgical resection, and recurrence in pituitary adenoma (PA). We reviewed a prospectively collected database of surgically treated PA between March 2016 and October 2017. Predictors for extent of resection and recurrence/progression were assessed with logistic and Cox regression analysis. Of the 183 patients, the tumor consistency was found soft in 107 (58.5%) patients, intermediate in 41 (22.4%) patients, and hard in 35 (19.1%) patients. The mean of ADC ratio was 0.92 ± 0.22 for hard tumor, 1.03 ± 0.22 for intermediate tumor, and 1.41 ± 0.62 for soft tumor (P < 0.001). The mean collagen content was 25.86% ± 15.00% for hard tumor, 16.05% ± 9.90% for intermediate tumor, and 5.00% ± 6.00% for soft tumor (P < 0.001). Spearman analysis showed a significant correlation between ADC ratio and collagen content (ρ = ? 0.367; P < 0.001). Gross-total resection (GTR) was obtained in 68.3% of patients, and multivariable logistic regression analysis showed that ADC ratio (OR, 12.135; 95% CI, 4.001–36.804; P < 0.001), giant PA (OR, 0.233; 95% CI, 0.105–0.520; P < 0.001), and invasion (OR, 0.459; 95% CI, 0.220–0.960; P = 0.039) were significantly predictive of GTR. Twenty-seven (14.8%) patients suffered recurrence/progression in the mean follow-up of 35.14 months. Invasion (HR, 2.728; 95% CI, 1.262–5.899; P = 0.011) was identified as independent predictors of recurrence/progression. ADC ratio of DWI could be used for preoperative assessment of tumor consistency, tumor collagen content, and extent of surgical resection, which might be useful in preoperative planning for patients with PA.
