Delayed periportal enhancement: a characteristic finding on contrast ultrasound in idiopathic portal hypertension

Purpose Differentiation of idiopathic portal hypertension (IPH) from cirrhosis is not always easy because of their similar clinical features. This prospective study aimed to use contrast-enhanced ultrasound (US) in studying dynamic behavior of microbubble for characteristic enhancement features in IPH. Methods The study had 101 subjects: 8 IPH, 47 cirrhosis, and 36 controls, and additional ten cirrhosis for data validation. Contrast-enhanced US with perflubutane microbubble agent was performed in the early-phase (0-60 s) to compare hepatic enhancements among the three groups. Results Onset time of enhancement in the hepatic artery was not different among the groups, but that in the portal vein was longer in cirrhosis (19.9 +/- 5.2 s; p = 0.0014) and IPH (22.9 +/- 5.0 s; p = 0.0007) than in controls (16.6 +/- 3.4 s). As for parenchymal enhancement, all controls showed homogeneous enhancement, while all IPH showed delayed periportal enhancement. Cirrhosis had three patterns: 14 with homogeneous enhancement, 28 with diffuse heterogeneous enhancement, and 5 with IPH-like delayed periportal enhancement. Homogeneous enhancement was more frequent in controls than in cirrhosis/IPH (p < 0.0001), and delayed periportal enhancement was more frequent in IPH than in control/cirrhosis (p < 0.0001). The duration of intensity difference between hypoenhancement/delayed enhancement area and surrounding parenchyma which exceeded the half of the mean value of the maximum intensity difference (8.75 dB for IPH, 6.95 dB for cirrhosis) was longer in IPH (15.6 +/- 6.9 s) than cirrhosis (10.2 +/- 5.3 s; p = 0.0119). The data in cirrhosis were validated in the additional ten subjects. Conclusions Delayed periportal enhancement on the sonograms based on perflubutane microbubble agent may be a characteristic of IPH.