Sampling variability of computer-aided fractal-corrected measures of liver fibrosis in needle biopsy specimens

Table 1 Fractal parameters of liver fibrosis measured in biopsies taken at different sites (mean ± SD)

Liver	Sections (n)	AF (%)	PF (μm)	D		W	H
				DA	DP
1	6	19.17 ± 10.98 (9.1-38.4)	6964.74 ± 3128.95 (4646.2-12328.6)	1.64 ± 0.06 (1.6-1.8)	1.56 ± 0.06 (1.5-1.7)	1178.82 ± 198.79 (897.9-1453.3)	0.35 ± 0.06 (0.3-0.5)
2	8	22.00 ± 7.99 (8.5-35.1)	3570.14 ± 1170.41 (1365.9-5240.7)	1.66 ± 0 06 (1.5-1.7)	1.57 ± 0.06 (1.4-1.7)	748.94 ± 129.68 (1365.9-5240.7)	0.34 ± 0.06 (0.4-0.6)
3	8	15.62 ± 8.73 (5.5-33.8)	4673.66 ± 4405.36 (907.6-15037.6)	1.62 ± 0.07 (1.5-1.8)	1.55 ± 0.07 (1.4-1.7)	881.40 ± 354.46 (460-1641)	0.37 ± 0.07 (0.3-0.6)
4	8	32.83 ± 6.35 (25-44.2)	7727.38 ± 4215.44 (2949.9-16341.1)	1.74 ± 0.04 (1.6-1.8)	1.64 ± 0.04 (1.6-1.7)	1103.06 ± 307.68 (701.7-1649.3)	0.26 ± 0.04 (0.3-0.4)
5	6	19.53 ± 11.06 (4.95-32.9)	6833.67 ± 3057.82 (3057.8-11213.4)	1.64 ± 0.07 (1.5-1.7)	1.56 ± 0.06 (1.5-1.6)	1172.91 ± 342.08 (666.1-1690.3)	0.35 ± 0.07 (0.4-0.5)
6	8	31.42 ± 15.22 (13.1-55.67)	7035.59 ± 3871.56 (2290.7-14153.6)	1.74 ± 0.07 (1.6-1.8)	1.66 ± 0.06 (1.6-1.8)	1155.17 ± 367.12 (793.7-1713.5)	0.25 ± 0.04 (0.2-0.4)
7	6	12.81 ± 5.26 (6.5-20.8)	6576.58 ± 4024.44 (2626.9-12294.2)	1.61 ± 0.05 (1.5-1.7)	1.55 ± 0.05 (1.5-1.6)	1121.75 ± 429.47 (717.8-1796)	0.38 ± 0.07 (0.4-0.5)
8	6	13.52 ± 6.09 (5.5-21.7)	5224.22 ± 3583.102 (1599.6-11107.4)	1.57 ± 0.07 (1.5-1.7)	1.49 ± 0.07 (1.4-1.6)	908.53 ± 363.51 (547.1-1363.4)	0.42 ± 0.07 (0.4-0.6)
9	8	12.34 ± 6.87 (6.7-23.9)	5087.80 ± 1619.29 (3081.7-6801.2)	1.62 ± 0.05 (1.6-1.7)	1.55 ± 0.05 (1.5-1.6)	1076.95 ± 15.20 (902.5-1328.3)	0.37 ± 0.05 (0.4-0.5)
10	8	18.87 ± 5.54 (9.8-25)	8133.72 ± 3459.80 (2699.6-12552.2)	1.68 ± 0.05 (1.6-1.8)	1.61 ± 0.06 (1.5-1.7)	1276.35 ± 421.98 (635.9-1834.8)	0.31 ± 0.05 (0.3-0.5)
11	8	18.74 ± 4.93 (9.7-25.2)	5760.81 ± 1698.43 (2602.6-7805.2)	1.63 ± 0.05 (1.6-1.7)	1.56 ± 0.05 (1.5-1.6)	958.96 ± 173.98 (632.4-1147.6)	0.34 ± 0.05 (0.4-0.5)
12	8	25.26 ± 11.35 (9.7-44.4)	5621.00 ± 2603.91 (1637.6-9839.8)	1.71 ± 0.06 (1.6-1.8)	1.62 ± 0.05 (1.5-1.7)	970.14 ± 255.81 (609.3-1455.8)	0.28 ± 0.06 (0.3-0.5)

N: Number of biopsy sections; A_F: Fractal rectified area; P_F: Fractal rectified perimeter; D_A: Ssurface fractal dimension; D_P: Ooutline fractal dimension; W: Wrinkledness; H: Hurst's exponent.

Table 2 Coefficent of variability of fibrosis surface, wrinkledness and Hurst's exponent calculated in biopsy specimens taken at different liver sites

		CV (%)
Patient	Sections (n)	AF	W	H
1	6	57.28	16.86	13.90
2	8	36.31	17.31	15.27
3	8	55.9	40.22	16.86
4	8	19.79	27.89	10.71
5	6	56.64	29.17	14.87
6	8	48.44	31.78	17.74
7	6	41.05	38.29	11.67
8	6	45.05	40.01	15.41
9	8	55.67	14.13	11.45
10	8	29.38	33.06	16.13
11	8	26.31	18.14	12.68
12	8	44.94	26.37	15.13

N: number of biopsy sections; A_F: fractal rectified area; W: wrinkledness; H: Hurst's exponent; CV: coefficient of variability.