NGHIÊN CỨU VAI TRÒ CỦA HỆ SỐ KHUẾCH TÁN BIỂU KIẾN TRONG ĐÁNH GIÁ MẬT ĐỘ U TUYẾN TUYẾN YÊN KÍCH THƯỚC LỚN TƯƠNG QUAN VỚI PHẪU THUẬT

Abstract

Objective: To determine the sensitivity and specificity of apparent diffusion coefficient (ADC) in differentiating tumor consistency in pituitary macroadenomas (PMA). Methods: A retrospective descriptive case series was conducted at People's Hospital 115 from September 1st, 2019, to June 30th, 2025. Forty-three patients with pituitary macroadenomas, who underwent magnetic resonance imaging (MRI) and surgical treatment were included, comprising 21 soft consistency and 22 fibrous consistency tumors. ADC values were measured in the tumor area, normal temporal lobe white matter, and normal brainstem. Ratios of tumor ADC to white matter (rADCtr) and to brainstem (rADCtn) were calculated. ROC curve analysis was performed to determine optimal cut-off values for differentiating tumor consistency. Results: The minimum and mean ADC values of the tumor center (ADCumin, ADCutb), as well as rADCtr and rADCtn were significantly higher in soft consistency tumors compared with fibrous consistency tumors (p < 0.01). With cutoff points for ADCumin and ADCutb of 0.622 × 10⁻³ mm²/s (sensitivity 90.48%, specificity 54.55%) and 0.661 × 10⁻³ mm²/s (sensitivity 80.95%, specificity 63.64%) for  differentiating the two PMA consistency groups. Similarly, a cutoff of 0.900 for the rADCtr ratio differentiated soft tumor consistency with sensitivity 76.19% and specificity 72.73%, and a cutoff of 0.833 for rADCtn (with sensitivity and specificity of 90.48% and 59.09%, respectively) also differentiated the two tumor consistency groups. Conclusion: ADC values of the tumor and their ratios to normal white matter or brainstem demonstrate relatively high diagnostic accuracy for differentiating tumor consistency in pituitary macroadenomas.