Clinical and Multimodal Imaging Features of Hepatic Inflammatory Pseudotumors: A Two-Center Retrospective Study

Objectives: Current literature on imaging characteristics of hepatic inflammatory pseudotumor (HIPT) is limited. This study aimed to analyze the contrast-enhanced ultrasound (CEUS) features in HIPT and compare them with contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI).

Methods: A total of 83 patients with histologically proven HIPT from two medical institutions were included in this study. All patients underwent CEUS within 1 week before surgery or biopsy. Some patients received additional CECT or CEMRI. B-mode ultrasound (BMUS) features, enhancement parameters of CEUS, CECT and CEMRI were analyzed. Chi-square test was used to compare the enhancement patterns and diagnostic sensitivity between CEUS and CECT/CEMRI.

Results: On the BMUS, HIPT mainly appeared hypoechoic (83.5%, 66/79), irregular shapes (62.0%, 49/79), heterogeneous echogenicity (72.2%, 57/79), and unclear boundary (65.8%, 52/79). A total of 61.5% (51/83) lesions exhibited mild hyper- or iso-enhancement in the arterial phase (AP), 59.0% (49/83) lesions had internal nonenhanced areas, and most lesions (71.1%, 59/83) showed early wash-out (<60 seconds) on the CEUS. There were significant differences between CEUS and CECT/CEMRI in enhancement intensity of AP and wash-out pattern (P < .05). The sensitivity in the diagnosis of HIPT among the three had no statistical difference (P>.05).

Conclusions: The CEUS features of HIPT lesions typically include mildly hyper-enhanced or iso-enhanced in AP, rapid wash-out in PVP, and often small nonenhanced areas within the mass. Furthermore, the wash-out pattern of CEUS and CECT/CEMRI are inconsistent, more akin to cholangiocarcinoma. The diagnostic efficacy of the three modalities is similar.