Abstract
BackgroundTo explore the application value of computed tomography (CT) texture analysis in differentiating atypical pancreatic neuroendocrine tumors (pNET) from pancreatic ductal adenocarcinomas (PDAC).Materials and methodsThis single‐center retrospective study was approved by local institutional review board, and the requirement for informed consent was waived. We retrospectively analyzed 127 patients with 50 PDACs and 77 pNETs in pathology database between January 2012 and May 2017.These patients successfully finished preoperative contrast‐enhanced CT test. Texture parameters (mean, median, 5th, 10th, 25th, 75th, 90th percentiles, skewness, kurtosis and entropy) were extracted from portal images and compared between PDAC and 77 pNET groups using proper statistical method. The optimal parameters for differentiating PDACs and atypical pNETs were gained through receiver operating characteristic (ROC) curves.ResultsOn the basis of arterial enhancement, 52 pNETs (67%, 52/77) were typical hypervascular and 25 pNETs (32%, 25/77) were atypical hypovascular. Compared with PDACs, atypical pNETs had statistically higher mean, median, 5th, 10th, and 25th percentiles (P = 0.006, 0.024, 0.000, 0.001, 0.021, respectively) and statistically lower skewness (P = 0.017). However, there were no difference for 75th, 90th percentiles, kurtosis and entropy between these two tumors (P = 0.232, 0.415, 0.143, 0.291, respectively). For differentiating PDACs and atypical pNETs, 5th percentile and 5th+skewness were optimal parameters for alone and combined diagnosis, respectively.ConclusionVolumetric CT texture features, especially combined diagnosis of 5th+skewness can be used as a quantitative tool to distinguish atypical pNETs from PDACs.
Highlights
Pancreatic neuroendocrine tumors are the second common tumor of pancreas originating from pancreatic islet cells.[1]
These atypical pancreatic neuroendocrine tumors (pNET) on computed tomography (CT) are difficult to be differentiated from pancreatic ductal adenocarcinomas(PDACs).[3]
For pNET patients, previous studies have reported that more aggressive surgery method could lead to higher morbidity and did not significantly improve overall survival compared with conservative resections.[6]
Summary
Pancreatic neuroendocrine tumors (pNETs) are the second common tumor of pancreas originating from pancreatic islet cells.[1]. PNET is characterized by hypervascular on CT arterial phase, recent studies have reported that up to 41.5% of pNETs may show atypical hypovascular enhancement pattern.[2]. These atypical pNETs on CT are difficult to be differentiated from pancreatic ductal adenocarcinomas(PDACs).[3]. Jung Hoon[11] and Sun Kyung et al[12] have evaluated the imaging characteristics of atypical hypovascular PNET and PDAC, respectively. They found duct dilatation in CT may be a helpful predictor for PDAC.[11]. This study selected the entire tumor as ROI for texture analysis and explored the optimal parameters for identifying PDAC and atypical pNET on contrast-enhanced CT
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