Objective: To assess morphological vascular changes due to an increase in liver fibrosis by using micro-flow imaging (MFI) of contrast-enhanced ultrasound.
Methods: MFI was performed in 47 patients who underwent liver biopsy, and in 10 normal cases. For 27/57 cases, we performed MFI twice in order to assess the reproducibility of the examination, thus yielding a total of 84 examinations. Seven physicians interpreted each case individually by assigning confidence levels for the presence or absence of three imaging features that were related to alteration of portal vein morphology: angle widening, tapering/interruption and tortuosity.
Results: Pearson's correlation coefficient between the average rating scores based on tortuosity and the histological fibrosis stage was 0.806 (p < 0.001). The diagnostic accuracy of the average area under the ROC curve, which was estimated by use of the confidence levels of tapering/interruption, tortuosity and angle widening, was 0.964 for F1 vs. F2-4, 0.968 for F1-2 vs. F3-4 and 0.910 for F1-3 vs. F4. The average correlation coefficient between the ratings on different images from the same patients was 0.838.
Conclusion: Assessment of morphological intrahepatic vascular changes on MFI may be useful for grading liver fibrosis.