Published online Jul 28, 2020. doi: 10.3748/wjg.v26.i28.4151
Peer-review started: April 6, 2020
First decision: April 26, 2020
Revised: May 8, 2020
Accepted: July 15, 2020
Article in press: July 15, 2020
Published online: July 28, 2020
Pancreatic ductal adenocarcinoma (PDA) is a malignancy with a high mortality rate and short survival time. The conventional computed tomography (CT) has been worldwide used as a modality for diagnosis of PDA. Also, it has been widely accepted that CT enhancement pattern is related to tumor angiogenesis and pathologic grade of PDA.
Although there is other modality, like perfusion CT that provide information about vascularity and fibrosis in the diseased pancreas, it has a smaller FOV, requires additional radiation exposure, and processing time. So, if there is any CT parameter that can predict pathologic grade of PDA, it would be useful for predicting prognosis of PDA using conventional CT.
In this study, we aimed to evaluate the relationship between the pathologic grade of pancreatic ductal adenocarcinoma and the enhancement parameters of contrast-enhanced CT.
In this retrospective study, 42 patients with PDA who underwent surgery after preoperative CT were selected. Two radiologists evaluated the CT images and calculated the value of attenuation at the aorta in the arterial phase and the pancreatic phase (VAarterial and VApancreatic) and of the tumor (VTarterial and VTpancreatic) by finding out four regions of interest. Ratio between the tumor and the aorta enhancement on the arterial phase and the pancreatic phase (TARarterial and TARpancreatic) was figured out through dividing VTarterial by VAarterial and VTpancreatic by VApancreatic. Tumor-to-aortic enhancement fraction (TAF) was expressed as the ratio of the difference between attenuation of the tumor on arterial and parenchymal images to that between attenuation of the aorta on arterial and pancreatic images.
A total of 42 PDAs were categorized into three groups: Well-differentiated (n = 13), moderately differentiated (n = 21), and poorly differentiated (n = 8). TAF differed significantly between the three groups (P = 0.034) but TARarterial (P = 0.164) and TARpancreatic (P = 0.339) did not. The value of TAF was statistically different among the three groups (P < 0.05).
TAF was statistically different among the three pathologic grade groups. So, the TAF might be correlated with histological finding of PDA. Therefore, calculation of TAF using conventional CT might be useful in predicting the pathologic grade of PDA.
The conventional CT has been useful modality for diagnosis of PDA. In our study, we suggest the CT enhancement parameter, TAF, could be used as a value for predicting pathologic grade of PDA. The pathologic grade is related to prognosis of PDA, then we can use conventional CT not only for diagnosis, but also for predicting pathologic grade and prognosis of PDA. Also, TAF may be obtained with conventional pancreatic CT, without additional radiation exposure and processing time, and is more useful for practical staging than perfusion CT parameters.