Gastric cancer with synchronous and metachronous hepatic metastasis predicted by enhancement pattern on multiphasic contrast-enhanced CT

Objective: The purpose of this study was to examine the relationship between the CT features of the primary-site gastric cancer and the concurrent existence or postoperative recurrence of hepatic metastasis. Materials and methods: From January 2013 to July 2016, 125 patients with advanced gastric cancer who were evaluated by gastroscopy and contrast-enhanced CT at our institution were included. Eleven patients had hepatic metastasis at the time of diagnosis (synchronous hepatic metastasis). Five patients had hepatic recurrence after surgery (metachronous hepatic metastasis, median follow-up period of 313 days), and another 56 patients had no hepatic recurrence during follow-up period (negative hepatic metastasis, median follow-up period of 1102 days). Two radiologists independently reviewed the CT images and they determined the peak enhancement phase, and then measured the CT attenuation value of the gastric lesion for each phase. We compared the parameters of synchronous, metachronous and negative hepatic-metastasis. We calculated diagnostic performance of CT for diagnosing synchronous and metachronous hepatic metastasis. Results: The peak enhancement was significantly diff; erent between the three groups for both readers (reader 1, p = 0.0001; reader 2, p = 0.0002). Most of the synchronous and metachronous hepatic metastasis had peak enhancement in the arterial or portal phase. The CT attenuation values of synchronous and metachronous hepatic metastasis were significantly higher than those of negative hepatic metastasis in the delayed phase according to both readers (reader 1, p = 0.0003; reader 2, p = 0.0002). In predicting synchronous hepatic metastasis using peak enhancement, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.7%, 89.3%, 57.1%, 94.3%, and 86.6% for reader 1, and 54.5%, 94.6%, 66.7%, 91.4%, and 88.1% for reader 2. In predicting metachronous hepatic metastasis, the sensitivity, specificity, PPV, NPV, and accuracy were 60.0%, 89.3%, 33.0%, 94.3%, and 86.9% for reader 1, and 40.0%, 94.6%, 40.0%, 94.6%, and 90.2% for reader 2. Conclusion: Our study showed that gastric cancer with synchronous and metachronous hepatic metastasis tends to show early enhancement with a washout pattern on contrast-enhanced CT. This feature would be helpful in image surveillance for synchronous or metachronous hepatic metastasis of gastric cancer.