Non-Invasive Assessment of SMAD4 Expression Status in Pancreatic Ductal Adenocarcinoma: Diagnostic Value of T1ρ-Weighted Imaging Combined with Clinical Parameters

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a malignancy with poor prognosis, where SMAD4 protein loss is closely associated with increased tumor aggressiveness and metastatic potential. Current assessment of SMAD4 expression relies on IHC of tumor tissue obtained by biopsy or resection, in which limited sampling may not represent intratumoral heterogeneity. T1ρ-weighted imaging, an emerging functional MRI technique, shows promise in characterizing tumor microstructural properties. This study aimed to evaluate the value of T1ρ imaging combined with conventional MRI sequences and clinical parameters for non-invasive prediction of SMAD4 protein expression status in PDAC.

Methods

This retrospective single-center study included 57 patients with histologically confirmed PDAC who underwent pretreatment MRI with T1ρ imaging between September 2024 and May 2025. Immunohistochemical analysis revealed SMAD4 intact in 28 tumors (49.1%) and SMAD4 loss in 29 tumors (50.9%). T1ρ values were measured and compared between SMAD4 intact and SMAD4 loss tumors. A multiparametric predictive model incorporating T1ρ values, lymph node metastasis status, and carbohydrate antigen 19-9 (CA19-9) levels was developed.