Imaging-based techniques have been developed to assess the stage of liver fibrosis, ultrasound elastography, and MR elastography have both shown good results in several clinical studies [15,16,17,18], with US elastography providing the advantage of lower cost and better availability than MR elastography [3, 5, 11, 12].
The use of 2-D SWE as a noninvasive method to assess liver fibrosis has grown rapidly, and new information regarding disease-specific liver stiffness is available since the consensus statement of the SRU in September 2015 [1, 2].
Despite this benefit, the use of noninvasive tests is favored due to the need for longitudinal monitoring and to safely extend screening to larger populations.
SWE is an acceptable noninvasive method for the diagnosis and staging of liver fibrosis and a more accurate than serum fibrosis panels (e.g., aspartate aminotransferase [AST] to platelet ratio index or FIB-4) in predicting significant or advanced fibrosis, and it can replace liver biopsy in certain situations.
Previous research has studied 2-D SWE liver fibrosis staging in patients with CLD, patients with HCV [19, 20], and patients with hepatitis B . These studies vary on the accuracy of elastography; however, the sensitivity, specificity, and diagnostic accuracy of SWE are comparable to biopsy results .
Ferraioli et al.  showed that SWE is a reliable and reproducible noninvasive method for the assessment of liver elasticity. Expert operators had a higher reproducibility of measurements over time than novice operators.
Zeng et al.  concluded that the ALT-adapted dual cut-offs of LSMs showed high accuracy for diagnosis of the presence or absence of significant fibrosis and cirrhosis in patients with chronic HBV infection.
Ma et al.  studied SWE in patients with chronic HBV and compare it with pathology. They found comparable results to our study, where F1 (5.60 ± 2.55 kPa), F2 (7.44 ± 3.43 kPa) (p = 0.01 < 0.05), F3 (8.71 ± 3.14 kPa), and F4 (10.87 ± 5.25 kPa) (p = 0.01 < 0.05). In this study, we combined chronic HBV and HCV due to a small number of patients and our results were as follows: F0–F1 fibrosis was 5.44 ± 0.43 kPa, F2 was 7.18 ± 0.48, and at stage F3 was 8.57 ± 0.35 kPa. The median stiffness (in kPa) for F0–F1 are as follows: 5.49 (IQR = 5.1–5.60), F2: 7.45 (IQR = 6.66–7.57), and F3: 8.57 (IQR = 8.3–8.82)
In addition, Tada et al.  studied SWE in patients with chronic HCV only and concluded that: SWE has an excellent ability for diagnosing significant liver fibrosis in CHC even when patients with cirrhosis are excluded, odds ratio, 2.52; 95% confidence interval, 1.49–4.28; P < 0.001.
The stage of fibrosis is important to determine prognosis, surveillance, and prioritizing the treatment [1, 2, 7,8,9, 19, 21, 26,27,28,29,30], by the new direct-acting antiviral (DAA) therapy for hepatitis C, and the decision to start treatment for hepatitis B in the absence of other indications, since F2 score of fibrosis in healthy-looking individuals indicates treatment which can be decided without liver biopsy .
Furthermore, Stasi et al.  concluded that liver stiffness before treatment is useful in predicting the response to treatment in HCV patients.
It is also a helpful tool in assessing donors for liver transplantation, as in some cases, many potential donors may present for donation, and noninvasive methods would be time-saving with a convenient cost-benefit outcome.
The wider disease causes in this study are a homogenous representation of chronic liver disease.
From a clinical perspective, it is more important to rule in or rule out significant disease than it is to provide an exact stage by using the METAVIR scoring system.
In this study, we conclude that 2-D SWE is a noninvasive method that can be used in assessing liver stiffness and can replace biopsy to assess liver fibrosis regardless of the cause.
This study population sample has a wide range of causes of liver disease beyond viral hepatitis that may cause heterogeneity in elasticity readings; however, a clear correlation between fibrosis stage and elasticity readings suggests that this method is likely valid in fibrosis measurements.
In addition, most of our sample is in the normal/mild fibrosis, therefore low power of the study in advanced fibrosis.
Also, different pathologies make the relative number of patients in each group which is relatively small.