title: Early detection of liver fibrosis in rats using 3-D ultrasound Nakagami imaging: a feasibility evaluation.
abstract: We investigated the feasibility of using 3-D ultrasound Nakagami imaging to detect the early stages of liver fibrosis in rats. Fibrosis was induced in livers of rats (n = 60) by intraperitoneal injection of 0.5% dimethylnitrosamine (DMN). Group 1 was the control group, and rats in groups 2-6 received DMN injections for 1-5 weeks, respectively. Each rat was sacrificed to perform 3-D ultrasound scanning of the liver in vitro using a single-element transducer of 6.5 MHz. The 3-D raw data acquired at a sampling rate of 50 MHz were used to construct 3-D Nakagami images. The liver specimen was further used for histologic analysis with hematoxylin and eosin and Masson staining to score the degree of liver fibrosis. The results indicate that the Metavir scores of the hematoxylin and eosin-stained sections in Groups 1-4 were 0 (defined as early liver fibrosis in this study), and those in groups 5 and 6 ranged from 1 to 2 and 2 to 3, respectively. To quantify the degree of early liver fibrosis, the histologic sections with Masson stain were analyzed to calculate the number of fiber-related blue pixels. The number of blue pixels increased from (2.36 ± 0.79) × 10(4) (group 1) to (7.68 ± 2.62) × 10(4) (group 4) after DMN injections for 3 weeks, indicating that early stages of liver fibrosis were successfully induced in rats. The Nakagami parameter increased from 0.36 ± 0.02 (group 1) to 0.55 ± 0.03 (group 4), with increasing numbers of blue pixels in the Masson-stained sections (p-value < 0.05, t-test). We concluded that 3-D Nakagami imaging has potential in the early detection of liver fibrosis in rats and may serve as an image-based pathologic model to visually track fibrosis formation and growth.
authors.affiliation: Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Ho
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Institute for Radiological Research, Chang Gung University / Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan. Electronic address: tsuiph@mail.cgu.edu.tw.
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Tsui
authors.affiliation: Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Electrical Engineering, Yuan Ze University, Chung Li, Taiwan.
authors.forename: Yung-Sheng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Surgery, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Chiung-Nien
authors.initials: CN
authors.lastname: Chen
authors.affiliation: Department of Applied Statistics and Information Science, Ming-Chuan University, Taoyuan, Taiwan. Electronic address: jjlin@mail.mcu.edu.tw.
authors.forename: Jen-Jen
authors.initials: JJ
authors.lastname: Lin
authors.affiliation: Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan.
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Chang
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D042241:Early Diagnosis; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D014463:Ultrasonography
keywords: Envelope statistics; Liver fibrosis; Nakagami imaging