Predictive value of preoperative MRI features for the Ki-67 index in well-differentiated G1/G2 pancreatic neuroendocrine tumors

BackgroundThe accurate estimation of the Ki-67 index of well-differentiated pancreatic neuroendocrine tumors (PanNET) not only guides curative management but also avoids unnecessary treatment.PurposeTo investigate whether magnetic resonance imaging (MRI) features could preoperatively discriminate the Ki-67 index of well-differentiated G1/G2 PanNETs and to construct an individualized predictive model through developing a MRI-based nomogram.Material and MethodsNinety-nine patients with G1/G2 PanNETs were divided into Ki-67 index <5% (n = 58) and Ki-67 index ≥5% groups (n = 41). Multiparametric MRI features of two groups were assessed via uni- and multivariate logistic regression models. The MRI-based nomogram was then developed based on multivariable logistic analysis; the effectivity of the nomogram was validated according to the C-index, calibrations, and a decision curve analysis.ResultsMRI features, including tumor size (odds risk [OR] = 7.791; P = 0.003) and the ADC values (OR = 0.245, P = 0.018) were ...