# Quantification of Liver Fibrosis--A Comparative Study
## 3 Literature Review
### Aim of Study  
#### 3.1.1 Early Studies Using Semi-Quantitative CPA Evaluations  
Early studies [11; 12; 13; 14] used microscopy image analysis as a more sensitive method to assess collagen quantitation in liver biopsies, recognizing the lack of other quantitative indexes and scoring techniques. Yet, these early studies noticed the disadvantages of image analysis as a quantitation technique, since this was time-consuming and needed sophisticated software and hardware equipment so that all small changes in fibrosis could be detected. Part of early studies [14; 15; 16; 17] reported a high correlation of the CPA with most of the staging and scoring systems, thus confirming the validity of the image analysis-based CPA assessment as a quantitative scoring system. Having that as a major result of several studies in the 90 s, researchers targeted the image analysis process, trying to develop and validate image analysis tools specifically designed for the CPA assessment. In this context, [PERSON] et al. [12] calculated the area of fibrosis through image analysis, which was used to assess the fibrogenic reduction of chronic non-A and non-B hepatitis activity after interferon (IFN)-a treatment. [PERSON] et al. [13] studied the quantitative determination of liver collagen and compared different staining dye combinations. [PERSON] et al. [14] relied on the correlation of the collagen density quantification results with those produced by the widespread Knodell scoring system. [PERSON] et al. [15] demonstrated the relationship between liver collagen content and histological grading of fibrosis based on a modified Knodell's score. [PERSON] et al. [16] studied the correlation between the Scheuer staging system and the area of fibrosis (analogous to the collagen index--CI). [PERSON] et al. [17] studied the correlation of the serum concentration of several potential markers of hepatic fibrosis, with two different scoring systems, whereas the area of fibrosis was calculated through DIA. [PERSON] et al. [18] and [PERSON] et al. [19] introduced the \"FibroQuant,\" an image analysis application for automated quantitation of CPA in histologic images. Specifically, in [PERSON] et al., FibroQuant was validated for the automatic segmentation of areas of fibrosis against images manually annotated from expert histopathologists. [PERSON] et al. aimed at the comparison of semi-quantitative methods with a DIA system for the evaluation of liver fibrosis in biopsies from patients with chronic hepatitis and different responses to IFN treatment. [PERSON] et al. [20] evaluated the impact of the size of biopsy needle samples on the grading and staging of fibrosis. According to them, since liver biopsy size can strongly affect the grading and staging of chronic viral hepatitis, only samples of 2 cm long (1.4 mm) were considered ideal to ensure the minimum number (4-6) of the complete portal tracts for reliable fibrosis quantification. In [PERSON] et al. [21], the \(\times\)40 magnification proved to be the ideal size for calculating the fibrotic areas. This magnification size was also selected by [PERSON] et al. [22]. They reported that the lower and higher than \(\times\)40 magnifications led to an inferior correlation between the DIA and semi-quantitative Ishak scoring system. [PERSON] et al. [23] aimed for assessing the validity of the calculated fibrosis ratio, computed by a DIA technique, as a measure of fibrosis stage in liver biopsies of patients with chronic hepatitis C (CHC). [PERSON] et al. [24] aimed to identify the factors leading to histological progression of fibrosis, in a cohort of patients with hepatitis C virus (HCV) without the intervention of therapy. [PERSON] et al. [25] claimed that the [PERSON] et al. study [23] could not reliably differentiate between mild fibrosis (Ishak 1-3) and advanced fibrosis or cirrhosis (Ishak 3-6). To address this, the goal was to correlate all Ishak stages with fibrosis rates (%) coming from DIA techniques, to improve the discrimination between varying levels of liver fibrosis.