Maximal accumulative respiration strain for the assessment of hepatic fibrosis

Early detection and grading of liver fibrosis are important for the treatment of chronic hepatitis. As the gold standard for the assessment of hepatic fibrosis, liver biopsy is invasive, and may cause hemorrhage and infection. Therefore, it is very important to develop noninvasive clinical methods for fibrosis assessment. In this paper, B-mode videos of the liver during peaceful respiration were acquired from two groups of people (8 healthy volunteers and 7 patients with biopsy-proven grade 4 fibrosis). All the videos were captured from the sagittal plane under the ensisternum where the hepatic tissue motion was almost in the imaging plane. After selecting a region of interest (ROI) in the hepatic tissue, the average strain of the hepatic tissue in the ROI was calculated from each adjacent frames. After that the accumulative strain during the whole respiration cycle was computed. Then the maximal accumulative respiration strain (MARS) during the respiration cycle was obtained. Significant difference between the MARS of these two groups was found. The mean MARS of the healthy group and fibrosis group were 29.45 and 15.19, respectively. The results indicated that the MARS was correlated to the hepatic fibrosis, and might be a potential parameter for hepatic fibrosis assessment.