An inexpensive and worldwide available digital image analysis technique for histological fibrosis quantification in chronic hepatitis C

Abstract

Hepatic fibrosis staging is based on semiquantitative scores. Digital imaging analysis (DIA) appears more accurate because fibrosis is quantified in a continuous scale. However, high cost, lack of standardization and worldwide unavailability restrict its use in clinical practice. We developed an inexpensive and widely available DIA technique for fibrosis quantification in hepatitis C, and here, we evaluate its reproducibility and correlation with semiquantitative scores, and determine the fibrosis percentage associated with septal fibrosis and cirrhosis. 282 needle biopsies staged by Ishak and METAVIR scores were included. Images of trichrome-stained sections were captured and processed using Adobe(®) Photoshop(®) CS3 and Adobe(®) Bridge(®) softwares. The percentage of fibrosis (fibrosis index) was determined by the ratio between the fibrosis area and the total sample area, expressed in pixels calculated in an automated way. An excellent correlation between DIA fibrosis index and Ishak and METAVIR scores was observed (Spearman's r = 0.95 and 0.92; P < 0.001, respectively). Excellent intra-observer reproducibility was observed in a randomly chosen subset of 39 biopsies with an intraclass correlation index of 0.99 (95% CI, 0.95-0.99). The best cut-offs associated with septal fibrosis and cirrhosis were 6% (AUROC 0.97, 95% CI, 0.95-0.99) and 27% (AUROC 1.0, 95% CI, 0.99-1), respectively. This new DIA technique had high correlation with semiquantitative scores in hepatitis C. This method is reproducible, inexpensive and available worldwide allowing its use in clinical practice. The incorporation of DIA technique provides a more complete evaluation of fibrosis adding the quantification to architectural patterns.

Quantitative assessment of liver fibrosis by digital image analysis: Relationship to Ishak staging and elasticity by shear‐wave elastography

“…Although DIA has been commonly used in animal models it has not been widely adopted in clinical practice which may be attributed to the relatively high cost of the software and the lack of methodological standardization. A number of studies have reported PA values ranging from 1% for stage 0 to a maximum of 65% for cirrhosis sections stained by trichrome and picrosirius Red …”

“…A number of studies have reported PA values ranging from 1% for stage 0 to a maximum of 65% for cirrhosis sections stained by trichrome and picrosirius Red. [4][5][6] Given the invasive nature and the relatively high cost of liver biopsy, widespread effort has been directed to utilize the 'non-invasive' surrogates of fibrosis assessment. Shear-wave elastography (SWE) is a relatively new technique for the measurement of tissue elasticity and has several advantages with respect to transient elastography (TE).…”

Digital image analysis in liver fibrosis: basic requirements and clinical implementation

“…Picrosirius red may generate better contrast difference between the collagen area and parenchyma, while the mottling and inconsistent colour tone and the lower contrast difference of trichrome may affect optimal thresholding, sometimes leading to technical artefacts which take time to eliminate manually. DIA method for liver fibrosis was shown to be highly reproducible by both picrosirius red (intra-class correlation coefficient (ICC) 0.970À0.999) [6,7] and trichrome stain (ICC 0.926À0.990) [5,14,15]. We suggest that trichrome stain may be reasonable for routine purposes to determine the morphometric fibrosis content in clinical practice, where cost and time may preclude the use of picrosirius red or other stains like collagen immunohistochemistry stains in the pathology laboratories.…”

“…Moderate to excellent correlations between fibrosis quantitity by PA and Ishak stages scores were reported by many previous studies. [7,14,15] This statistical technique was criticized as an incorrect methodology [16] since the number values assigned to the stages are categorical labels which are ordinal in nature and do not specifically represent a quantification in a numerical sense; e.g. Ishak stage 3 does not correspond to three times the fibrosis quantity of stage 1.…”

Application of texture analysis on parametricT1andT2maps for detection of hepatic fibrosis

“…Two analyses were performed by dividing specimens into <10.1% vs. ≥10.1% and <19.0% vs. ≥19.0%. Thresholds were chosen to approximate the digital image analysis cutoffs for differentiating Ishak fibrosis scores 0–2 from 3–6 and 0–3 from 4–6 . AUCs were classified as follows: 0.50–0.59, poor; 0.60–0.69, fair; 0.70–0.79, good; 0.80–0.89, very good; 0.90–1.0, excellent.…”