Evaluation of Occult Liver Metastases in Pancreatic Adenocarcinoma by Diffusion‐Weighted Related Magnetic Resonance Imaging

Occult liver metastases in patients with pancreatic ductal adenocarcinoma (PDAC) affects treatment strategies and prognosis. Diffusion-weighted imaging (DWI), including non-Gaussian DWI may help to evaluate tumor biological behavior. To evaluate the diagnostic value of DWI parameters in predicting occult liver metastases in patients with PDAC. Prospective. 115 participants with pathologically confirmed PDAC (male = 71, mean age = 59.8 ± 9.9 years). Occult liver metastasis was defined as those detected by CT or MRI within 6 months of pancreatectomy. DWI, intravoxel incoherent motion (IVIM) imaging and diffusion kurtosis imaging (DKI) echo planar imaging sequences at 1.5 T. Apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), mean apparent diffusion (MD) and mean kurtosis (MK) were measured. In addition, age, sex, body mass index, neutrophil-to-lymphocyte ratio (NLR) and carbohydrate antigen 19-9 (CA 19-9) level were recorded. Logistic regression analysis, area under the receiver operating characteristic curve (AUC), DeLong test. Two tailed P value < 0.05 was considered significant. Results 23 of 115 (20%) participants had occult liver metastases. Multivariable analysis revealed D [odds ratio (OR) = 0.220], NLR (OR = 1.391) and CA19-9 level (OR = 1.002) were independent risk factors for occult liver metastases. The AUCs were 0.772 for the combination of NLR and CA19-9 level, and 0.848 for the combination of D, NLR and CA19-9 level, without significant difference between the two models (P = 0.055). A combination of D, NLR and CA19-9 level may be useful in the prediction of occult liver metastases in patients with PDAC. 2. Stage 2.