Apparent Diffusion Coefficient Values for Neuroendocrine Liver Metastases.

Rationale and Objectives: We aimed to investigate whether there are any differences in apparent diffusion coefficient (ADC) values obtained from liver metastases due to gastroenteropancreatic neuroendocrine tumors (GEP-NET) and adenocarcinomas.
Materials and Methods: We included 54 patients with 167 liver metastases due to gastroenteropancreatic tumors. We divided the patients into two groups as liver metastases due to GEP-NETs (seven patients with 51 lesions, mean age: 48) and adenocarcinomas (47 patients with 116 lesions, mean age: 61.2). We used the independent samples t-test to compare the ADC and ADC _mean values of the two groups and performed a receiver-operating characteristic analysis.
Results: ADC and ADC _mean values were significantly lower in the GEP-NET group compared with the adenocarcinoma group. Receiver-operating characteristic curve analysis showed a significant difference for ADC and ADC _mean values, and area under the curve values were 0.733 and 0.790, respectively. The cut-off values were 933x10 ^-6 mm ² /s for ADC and 801x10 ^-6 mm ² /s for ADC _mean . Diagnostic accuracies of ADC (Sensitivity = 80.2, Specificity = 64.7, PPV = 83.8, NPV = 58.9) and ADC _mean (Sensitivity = 63.8, Specificity = 82.4, PPV = 89.2, NPV = 50) were calculated in differentiating adenocarcinoma metastases from GEP-NET metastases.
Conclusion: The lower ADC and ADC _mean values of liver metastases suggest GEP-NET rather than adenocarcinomas. ADC and ADC _mean values obtained from liver metastases may be used to differentiate NETs from adenocarcinomas.
(Copyright © 2020 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)