Objective: Hepatocyte-specific contrast agents are used to help characterize liver lesions. However, there are no studies evaluating the utility of these agents in detecting or diagnosing pediatric liver lesions. The purpose of this study is to assess the impact of the hepatocyte phase of imaging on lesion detection, tumor staging and diagnostic confidence.
Materials and methods: All patients undergoing an MRI between September 2010 and August 2012 using gadoxetate disodium as the contrast agent were included in this study. Each exam was duplicated so that one copy contained all sequences, including the hepatocyte phase of imaging, and the other copy contained all sequences except the hepatocyte phase of imaging. One reviewer evaluated all exams in a blinded, random fashion. Data tracked included imaging diagnosis, confidence in diagnosis, number of lesions and PRETEXT grade. The imaging diagnosis was compared to histopathology, when available. Data were analyzed for the study population as well as the subset of patients diagnosed with focal nodular hyperplasia (FNH).
Results: There were 112 patients (56 male; mean age: 9.25 years) included in this study. A total of 33 patients had a malignant tumor and the remainder had either a benign lesion or no lesion. The addition of the hepatocyte phase of imaging significantly improved the diagnostic confidence for all patients (P < 0.0001) as well as specifically for patients diagnosed with FNH (P = 0.003). In nearly a quarter of patients, the hepatocyte phase of imaging allowed the reviewer to detect additional lesions (P = 0.005). In the patients with a malignant tumor, the addition of the hepatocyte phase of imaging changed the PRETEXT grade in 7/30 patients although the results were not significant (P = 0.161).
Conclusion: The addition of the hepatocyte phase of imaging helps to improve lesion detection and increase the diagnostic confidence for all liver tumors, as well as for FNH in particular.