Pancreatic ductal adenocarcinoma with synchronous and metachronous hepatic metastasis predicted by contrast-enhanced ultrasound

Background: Contrast-enhanced ultrasound (CEUS) has proven valuable in diagnosing benign and malignant pancreatic diseases, but its value in evaluating hepatic metastasis remains to be further explored. This study investigated the relationship between CEUS features of pancreatic ductal adenocarcinoma (PDAC) and concomitant or recurrent liver metastases after treatment. Methods: This retrospective study included 133 participants with PDAC who were diagnosed with pancreatic lesions with CEUS at Peking Union Medical College Hospital from January 2017 to November 2020. According to the CEUS classification methods in our center, all the pancreatic lesions were classified as either with rich or poor blood supply. Additionally, quantitative ultrasonographic parameters were measured in the center and periphery of all pancreatic lesions. CEUS modes and parameters of the different hepatic metastasis groups were compared. The diagnostic performance of CEUS was calculated for diagnosing synchronous and metachronous hepatic metastasis. Results: The proportions of rich blood supply and poor blood supply were 46% (32/69) and 54% (37/69), respectively, in the no hepatic metastasis group; 42% (14/33) and 58% (19/33), respectively, in the metachronous hepatic metastasis (MHM) group; and 19% (6/31) and 81% (25/31), respectively, in the synchronous hepatic metastasis (SHM) group. The wash-in slope ratio (WIS ratio) between the center of the lesion and around the lesion and peak intensity ratio (PI ratio) between the center of the lesion and around the lesion had higher values in the negative hepatic metastasis group (P<0.05). In predicting synchronous and metachronous hepatic metastasis, the WIS ratio had the best diagnostic performance. The sensitivity (SEN), specificity (SPE), accuracy (ACC), positive predictive value (PPV), and negative predictive value (NPV) were 81.8%, 95.7%, 91.2%, 90.0%, and 91.7%, respectively, for MHM; and 87.1%, 95.7%, 93.0%, 90.0%, and 94.3%, respectively, for SHM. Conclusions: CEUS would be helpful in image surveillance for synchronous or metachronous hepatic metastasis of PDAC.