Elsevier

Academic Radiology

Volume 28, Supplement 1, November 2021, Pages S81-S86
Academic Radiology

Original Investigation
Apparent Diffusion Coefficient Values for Neuroendocrine Liver Metastases

https://doi.org/10.1016/j.acra.2020.10.024Get rights and content

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 ADCmean values of the two groups and performed a receiver-operating characteristic analysis.

Results

ADC and ADCmean 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 ADCmean values, and area under the curve values were 0.733 and 0.790, respectively. The cut-off values were 933x10-6 mm2/s for ADC and 801x10-6 mm2/s for ADCmean. Diagnostic accuracies of ADC (Sensitivity = 80.2, Specificity = 64.7, PPV = 83.8, NPV = 58.9) and ADCmean (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 ADCmean values of liver metastases suggest GEP-NET rather than adenocarcinomas. ADC and ADCmean values obtained from liver metastases may be used to differentiate NETs from adenocarcinomas.

Section snippets

INTRODUCTION

Neuroendocrine tumors (NET) arise from enterochromaffin cells that are mainly found in the gastrointestinal tract (1). Liver is the most common site of these metastases, with up to 60% of prevalence (2,3).

The incidence of NETs is increasing because of widely used diagnostic modalities and improved clinical attention (4). Magnetic resonance imaging (MRI) is the best diagnostic modality to detect liver metastases due to NETs (NET-LM) (2,3,5). As hypervascular tumors, NET-LMs classically enhance

Patients

We retrospectively examined 85 patients with liver metastases due to gastrointestinal and pancreatic cancer in our hospital's medical records. Inclusion criteria were determined as histopathological confirmation of the primary or metastatic lesion, histopathologically diagnosed with adenocarcinoma or grade 1 and grade 2 NET, having liver metastases at the initial diagnosis, no history of chemotherapy at initial imaging and the presence of pretreatment MRI of the abdomen.

Exclusion criteria were

RESULTS

GEP-NET was diagnosed in seven patients (two females, five males, with a mean age of 48) with 51 (30.5%) liver metastases, and adenocarcinoma was diagnosed in 47 patients (19 females, 28 males, with a mean age of 61.2) with 116 (69.5%) liver metastases.

There was no statistically significant difference between GEP-NET and adenocarcinoma in terms of gender (p = 0.693), tumor size (p = 0.420), or tumor localization (p = 0.442). GEP-NET patients were significantly younger than the adenocarcinoma

DISCUSSION

The current study showed lower ADC and ADCmean values in GEP-NET liver metastases compared with the liver metastases due to the gastro-enteropancreatic adenocarcinoma. We reached AUC rate of 0.733 and 0.790 for ADC and ADCmean values, respectively.

As highly vascular tumors, liver metastases due to NETs show hypervascularity at arterial phases regardless of the imaging modality (1). There are several studies in the literature on the importance of the typical contrast pattern to detect and

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Cited by (4)

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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