Liver metastases in pancreatic ductal adenocarcinoma: a predictive model based on CT texture analysis.

PURPOSE: To develop a predictive model for liver metastases in patients with pancreatic ductal adenocarcinoma (PDAC) based on textural features of the primary tumor extracted by computed tomography (CT) images. MATERIALS AND METHODS: Patients with a pathologically proved PDAC who underwent CT between December 2020 and January 2022 were retrospectively identified. Treatment-naïve patients were included. Sex, age, tumor size, vascular infiltration and 39 arterial and portal phase textural features were analyzed. The variables significantly correlated to tumor size according to the Pearson's product-moment correlation test were excluded from analysis; the remaining variables were compared between metastatic (M +) and non-metastatic (M-) patients using Fisher's or Mann-Whitney test. The features with a significant difference between groups were entered into a binomial logistic regression test to develop a predictive model for liver metastases. RESULTS: This study included 220 patients. Eight variables (tumor size, arterial HU_MAX, arterial GLRLM_LRLGE, arterial GLZLM_SZHGE, arterial GLZLM_LZLGE, portal GLCM_CORRELATION, portal GLRLM_LRLGE, and portal GLZLM_SZHGE) were significantly different between groups. The logistic regression model was statistically significant (χ2 = 81.6, p < .001) and correctly classified 80.9% of cases. Sensitivity, specificity, positive and negative predictive values of the model were 58.6%, 91.3%, 75.9% and 82.5%, respectively. The area under the ROC curve of the model was 0.850 (95% CI, 0.793-0.907). Tumor size, arterial HU_MAX, arterial GLZLM_SZHGE and portal GLCM_CORRELATION were significant predictors of the likelihood of liver metastases, with odds ratios of 1.1, 0.9, 1, and 1.49, respectively. CONCLUSIONS: CT texture analysis of PDAC can identify features that may predict the likelihood of liver metastases.

Imaging of the Liver and Pancreas: The Added Value of MRI.

MR is a powerful diagnostic tool in the diagnosis and management of most hepatic and pancreatic diseases. Thanks to its multiple sequences, the use of dedicated contrast media and special techniques, it allows a multiparametric approach able to provide both morphological and functional information for many pathological conditions. The knowledge of correct technique is fundamental in order to obtain a correct diagnosis. In this paper, different MR sequences will be illustrated in the evaluation of liver and pancreatic diseases, especially those sequences which provide information not otherwise obtainable with other imaging techniques. Practical MR protocols with the most common indications of MR in the study of the liver and pancreas are provided.

Magnetic resonance imaging short protocols for intraductal papillary mucinous neoplasm (IPMN) surveillance: The time has come.

BACKGROUND/OBJECTIVES: To analyze the diagnostic performance of three short magnetic resonance imaging (MRI) protocols for the follow-up of pancratic intraductal papillary mucinous neoplasms (IPMN). METHODS: Follow-up MRI examinations of 287 patients with IPMN performed in two centers were retrospectively retrieved. Four MRI protocols were identified as follows: T1-weighted (T1w), T2-weighted (T2w), and MRCP sequences (protocol 1); T1w, T2w, MRCP, and diffusion-weighted (DWI) sequences (protocol 2); T1w, T2w, MRCP, and post-contrast T1w-sequences (protocol 3); and a comprehensive protocol including all previous sequences (protocol 4). Three radiologists with different experience in abdominal imaging expressed their opinion upon the optimal patient's management upon the evaluation of each protocol. Intra-and inter-observer agreement and concordance with the clinical decision expressed by a pancreatic surgeon were calculated with Cohen's kappa test. RESULTS: 223 patients were included (66±10 years; 92 men, 131 women). 143 patients had branch-duct-IPMNs, 25 main-duct-IPMNs and 55 mixed-type-IPMNs. 79 patients underwent surgery, resulting in 52 high-grade dysplasia (HGD) and 27 low-grade dysplasia (LGD). Concordance for the expert reader between protocols 1, 2 and 3 and the actual clinical decision were 0.63, 0.72, and 0.74 respectively (95% CI, 0.53-0.73, 0.63-0.81, and 0.65-0.83). Inter-observer agreement between reader 1 and reader 2, reader 1 and reader 3, and reader 2 and reader 3 were: 0.71, 0.50, and 0.75 for protocol 1 (95% CI, 0.63-0.81, 0.40-0.60, and 0.66-0.84);0.68, 0.54, and 0.84 for protocol 2 (95% CI, 0.59-0.77, 0.44-0.64, and 0.76-0.91); and 0.77, 0.65, and 0.86 for protocol 3 (95% CI, 0.69-0.86, 0.55-0.74, and 0.80-0.93). CONCLUSIONS: Short MRI protocol is suitable for IPMN surveillance.

Correlation between ADC Histogram-Derived Metrics and the Time to Metastases in Resectable Pancreatic Adenocarcinoma.

Background: A non-invasive method to improve the prognostic stratification would be clinically beneficial in patients with resectable pancreatic adenocarcinoma (PDAC). The aim of this study was to correlate conventional magnetic resonance (MR) features and the metrics derived from the histogram analysis of apparent diffusion coefficient (ADC) maps, with the risk and the time to metastases (TTM) after surgery in patients with PDAC. Methods: pre-operative MR examinations of 120 patients were retrospectively analyzed. Patients were grouped according to the presence (M+) or absence (M−) of metastases during follow-up. Conventional MR features and histogram-derived metrics were compared between M+ and M− patients using the Fisher's or Mann−Whitney tests; receiver operating characteristic (ROC) curves were constructed for the features that showed a significant difference between groups. A Cox regression analysis was performed to identify the features with a significant effect on the TTM, and Kaplan−Meier curves were constructed for significant features. Results: 68.3% patients developed metastases over a mean follow-up time of 29 months (range, 3−54 months). ADC skewness and kurtosis were significantly higher in M+ than in M− patients (p < 0.001). Skewness had a significant effect on the risk of metastases (hazard ratio­HR = 5.22, p < 0.001). Patients with an ADC skewness ≥0.23 had a significantly shorter TTM than those with a skewness <0.22 (11.7 vs. 30.8 months, p < 0.001). Conclusions: pre-operative histogram analysis of ADC maps provides parameters correlated to the metastatic potential of PDAC. Higher ADC skewness seems to be associated with a significantly shorter TTM in patients with resectable PDAC.