|Year : 2021 | Volume
| Issue : 1 | Page : 12-17
Comparison of Fibroscan with Liver biopsy in non-alcoholic fatty liver disease (NAFLD) patients for assessing fibrosis
Ganraj Bhat1, SR Likitha1, Rashmi Krishnappa1, Gaurav Agarwal2, Ravi Kiran2, TC Nagesh Kumar3
1 Department of Pathology, Ramaiah Medical College, Bengaluru, Karnataka, India
2 Department of Gastroenterology, Ramaiah Medical College, Bengaluru, Karnataka, India
3 Department of Internal Medicine, Ramaiah Medical College, Bengaluru, Karnataka, India
|Date of Submission||10-Apr-2020|
|Date of Decision||08-May-2020|
|Date of Acceptance||18-Oct-2020|
|Date of Web Publication||30-Jun-2021|
Dr. Rashmi Krishnappa
Department of Pathology, Ramaiah Medical College, Bengaluru - 560 060, Karnataka
Source of Support: None, Conflict of Interest: None
Background: The prevalence of nonalcoholic fatty liver disease (NAFLD) in India varies from 9 to 35%. NAFLD is one of the most common causes of chronic liver disease worldwide. Liver biopsy, which is the gold standard for diagnosing NAFLD is an invasive procedure with potential adverse effects and large inter- and intra-observer variability. Hence, various noninvasive markers are being explored to assist in the diagnosis of NAFLD. Fibroscan measures liver stiffness through estimation of the velocity of propagation of a shear wave through liver tissue. Very few studies have addressed the accuracy of fibroscan versus liver biopsy.
Objectives: To grade liver fibrosis in the patients and compare fibrosis score by fibroscan with that of liver biopsy in NAFLD.
Materials and Methods: An observational study of 72 subjects who had presented with fatty liver on ultrasound and further subjected to fibroscan at the outpatient department of gastroenterology and have undergone liver biopsy (gold standard) for confirmation in the Department of Pathology, Ramaiah Medical College. The study was done from January 2017 to December 2018. After routine processing, liver biopsies were categorized into four subgroups depending on the fibrosis score such as F1 (perivenular fibrosis), F2 (periportal fibrosis), F3 (bridging fibrosis), and F4 (cirrhosis) and was compared with fibroscan scoring, which was based on the degree of fibrosis.
Results: Our study revealed that in the subgroup of NAFLD patients with F1, F2, F3 fibrosis on biopsy, the mean fibroscan values were 11.84 ± 9.23, 16.98 ± 18.85, 21.93 ± 5.85, respectively, which overestimate the fibrosis score (2.5–7.5 Kpa), (7.6–10 Kpa), (10.1–13 Kpa), respectively, and in F4 fibrosis, the mean fibroscan value was 33.41 ± 17.39 and in concordance with the fibrosis score (>13 Kpa).
Conclusion: Fibroscan overestimates the fibrosis score in the early stages of NAFLD, whereas, it has high accuracy in detecting advanced fibrosis and cirrhosis. Hence, it can be concluded that transient elastography is a good adjunctive tool in NAFLD patients with advanced fibrosis.
Keywords: Fibroscan, fibrosis score, liver biopsy, nonalcoholic fatty liver disease
|How to cite this article:|
Bhat G, Likitha S R, Krishnappa R, Agarwal G, Kiran R, Nagesh Kumar T C. Comparison of Fibroscan with Liver biopsy in non-alcoholic fatty liver disease (NAFLD) patients for assessing fibrosis. Niger J Gastroenterol Hepatol 2021;13:12-7
|How to cite this URL:|
Bhat G, Likitha S R, Krishnappa R, Agarwal G, Kiran R, Nagesh Kumar T C. Comparison of Fibroscan with Liver biopsy in non-alcoholic fatty liver disease (NAFLD) patients for assessing fibrosis. Niger J Gastroenterol Hepatol [serial online] 2021 [cited 2022 May 25];13:12-7. Available from: https://www.njghonweb.org/text.asp?2021/13/1/12/320308
| Introduction|| |
Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease worldwide. The prevalence of NAFLD in India varies from 9% to 35%. In 1980, Ludwig et al. from the Mayo Clinic coined the term nonalcoholic steatohepatitis (NASH) to describe the liver diseases observed in middle-aged patients with abnormal liver biochemical test results and histologic evidence of alcoholic hepatitis without any significant history of alcohol intake.
The definition of NAFLD as per the American Association for the Study of Liver Diseases requires the following (a) evidence of hepatic steatosis, either by imaging or by histology and (b) there should be no causes for secondary hepatic fat accumulation such as significant alcohol consumption, use of medication or hereditary disorders.
NAFLD is defined by the presence of steatosis in >5% of hepatocytes according to histological analysis or by a proton density fat fraction >5.6% assessed by proton magnetic resonance spectroscopy or quantitative fat/water selective magnetic resonance imaging with insulin resistance. These patients present with simple steatosis, which carries a good long-term prognosis. However, patients with NASH are at risk of progressive fibrosis, cirrhosis and hepatocellular carcinoma. Patients with NASH-related cirrhosis may have a poor prognosis.
The incidence of NAFLD has been investigated in a limited number of studies. According to three studies conducted in India, the incidence of NAFLD was 3.1%, 2.9%, and 10%.,, The reported prevalence of NAFLD in the other four studies are 20%, 51%, 12.2%, and 31%, respectively.,,, On the other hand, the estimated prevalence of NASH is lower, ranging from 3% to 5%.
Establishing a definitive diagnosis of NAFLD requires both clinical and histological data. Liver biopsy is the gold standard criteria to diagnose NAFLD and its components. Various noninvasive markers are being explored to assist in the diagnosis of NAFLD because liver biopsy is an invasive procedure. Fibroscan also known as transient elastography, measures liver stiffness through estimation of velocity of propagation of a shear wave through liver tissue. Very few studies have been done to compare the accuracy of fibroscan and liver biopsy. This study is done to investigate the accuracy of the fibroscan and liver biopsy in cases of NAFLD.
| Materials and Methods|| |
This is an observational study which included 72 subjects presenting to Medicine/Gastroenterology services of our hospitals who met the inclusion criteria during the study period 2 year between January 2017 and December 2018.
- All patients attending the outpatient department of our hospital and found to have deranged liver enzymes and who were diagnosed with fatty liver on ultrasound.
- Adults <75 years of age.
- History of alcohol intake >20 g per day (during the previous 5 years)
- Presence of HBsAg, Anti HCV, or HIV antibodies
- Biliary obstruction on ultrasonography
- Presence of malabsorption
- History of chronic drug use
- Pregnancy and those with any cardio-respiratory comorbidities
- Besides, patients who fulfilled inclusion criteria but not giving consent were excluded.
Method of data collection
Patients with unexplained deranged liver function tests on investigations, with ultrasound suggestive of fatty liver, were included in the study. On ultrasound, the liver was hyperechoic, with the echotexture of the liver being brighter than the kidney, with blurred vascular margins and deep attenuation of the ultrasound signal. Patients initially underwent fibroscan and relevant other lab investigations to identify the high-risk groups. The high risk groups included diabetes (fasting blood sugar levels >126 g/dL); metabolic syndrome (diagnosed on the basis of NCEP-ATP III criteria); body mass index (BMI) >30 kg/m2; serum aspartate aminotransferase/alanine aminotransferase greater than the upper limit of normal (40 IU/mL); and hypothyroidism (serum thyroid-stimulating hormone >5.5 IU/mL).
Fibroscan measurements were performed Fibroscan was done on the liver spaces with the patient lying in dorsal decubitus with the right arm in maximum abduction. Ten successful acquisitions were performed on each patient. The liver stiffness was expressed in kilopascals (Kpa).
After informed consent, yes all the patient underwent biopsy with 16G needle. The minimum length of the biopsy was 2 cm comprising 8 portal triads. All the biopsies were received in 10% formalin. After gross examination, the biopsies were processed as per standard protocol and paraffin-embedded tissue blocks were made. Paraffin sections of 3–5 μm were cut and stained with hematoxylin and eosin.
Special stains such as reticulin stain and Masson's trichrome stain were performed to score the fibrosis. The collagen stained black in reticulin stain and stained blue in Masson's trichrome. The stained slides were interpreted and graded depending on the degree of fibrosis into four subgroups such as F1 (perivenular fibrosis), F2 (periportal fibrosis), F3 (bridging fibrosis), and F4 (cirrhosis).
All biopsy specimens were analyzed by two histopathologists who were blinded to the other test results. The data were documented in a structural pro forma.
Data were arranged as frequency distribution tables and ANOVA with Fischer's exact test. To validate the fibro scan in detecting fibrosis, the sensitivity and specificity were determined and its statistical significance was assessed.
| Results|| |
The study group included 72 patients with a mean age of 42.47 ± 17.27 years and a predominance of females. Male: female ratio was 1:1.7. The mean BMI of the studied population was 25.81 ± 6.51. Underweight subjects accounted for 19%, while 33.5% were overweight and 17% were obese [Figure 1].
|Figure 1: (a) Body mass index (kg/m2) of patients studied (b) co-morbid conditions in patients studied|
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In the studied population, majority had diabetes mellitus. None of the patients had hypothyroidism. [Figure 2] Among the diabetic patients 15% of cases had diabetes for a duration of >10 years, 11.1% had diabetes for a duration of 5–10 years, 8.3% had diabetes for a duration of 3–5 years, 9.7% had diabetes for 1–2 years.
|Figure 2: (a) Photomicrograph under low power view (×10) showing periportal fibrosis (F2) (b) photomicrograph (×10) showing bridging fibrosis (F3) (c) photomicrograph showing Multiple nodules separated by fibrosis with fatty change of hepatocytes. (F4) (d) Photomicrograph showing reticulin stain positive in F4 case|
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In the population studied, 23.6% of cases had ANA positivity and 16.7% cases had pretest scores suggestive of autoimmunehepatitis.
Model for end-stage disease (MELD) was studied and observed that 37.5%, 51.4%, 8.3% and 2.8% cases had MELD scores <10, 10–18, between 19–24, and >24 with a mean ± standard deviation: 12.07 ± 5.05 [Table 1].
All the high-risk individuals underwent liver biopsies. The biopsy samples were considered adequate with a minimum of 8 portal tracts. It was noted that rosette formation was seen in 15.3%, plasma cell infiltration was seen in 13.9%, interphase hepatitis was noted in 27.8%, caseating necrosis was seen in 1.4%, chronic hepatitis was seen in 1.4%, the copper deposition was noted in 6.9% and diffuse cholestasis was noted in 4.2% of the patients studied.
The spectrum of diagnosis among the histopathological findings showed 63% having FLD. 20.8% had autoimmune hepatitis (AIH), 2.8% had overlap of AIH and FLD, 4.2% had benign recurrent intrahepatic cholestasis and Wilsons each, and 1.4% biopsies were suggestive of chronic hepatitis, Wilsons disease with AIH and primary sclerosing cholangitis with AIH [Table 2].
|Table 2: Fibro scan values in patients with F1, F2, F3, F4 fibrosis in nonalcoholic fatty liver disease subgroup|
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Liver biopsies were categorized into four subgroups depending on the different grades of fibrosis such as F1 (perivenular fibrosis), F2 (periportal fibrosis), F3 (bridging fibrosis), and F4 (cirrhosis).
Out of forty-six patients diagnosed to have NAFLD, 11% and 24% of individuals had stage 1 and 2 fibrosis. 24% and 41% of individuals had stage 3 and 4 fibrosis.
Comparison of various clinical characteristics in the NAFLD subgroup was made. The subgroup of patients with F4 fibrosis had low platelet count of 1.96 ± 0.80 lacs/cumm as compared to F1, F2, and F3 fibrosis. However, the P value was not significant. Higher serum creatinine levels were seen in patients with F4 fibrosis 1.16 ± 0.37 mg/dl as compared F1 fibrosis, which had creatinine levels of 0.82 ± 0.18 mg/dl and was statistically significant (P = 0.027) [Table 3].
|Table 3: A Comparison of clinical variables in nonalcoholic fatty liver disease subgroup|
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Fibroscan was carried out in all the enrolled patients. Twenty percent of the cases had fibroscan value of <7.5 kpa, 30.6% cases had fibro scan value ranging between 7.6 and 13 kpa, and 48% of the cases had fibroscanvalues >13 kpa with mean of 17.06 kpa.
As per the accepted norms in patients with NAFLD, the values indicating different stages of fibrosis are: F1-2.5Kpa to 7.5 Kpa, F2-7.6 Kpa to 10 Kpa, F3-10.1 Kpa to 13 Kpa, F 4–>13.1 Kpa.
Fibroscan values of the NAFLD subgroup are shown in.
The mean of F1 fibrosis: 11.84 ± 9, F2 fibrosis: 16.98 ± 18.85, F3 fibrosis: 21.93 ± 5.85, for F4 fibrosis: 33.41 ± 17.39.
| Discussion|| |
Among NAFLD patients, about one-third (33.3%) of the patients were overweight with a BMI between 25 and 30 kg/m2 and around 18 patients (41%) of the patients were obese. Interestingly 11 patients had BMI either in the normal range or underweight. However, the mean BMI of the studied subjects was 25.81 ± 6.51 kg/m2.
The subgroup of patients with F3 fibrosis showed a higher BMI of 31.27 ± 6.05 kg/m2 as compared to F1 fibrosis, however, this was not significant.
It was noted that 65% of the subjects had diabetes mellitus in a study conducted by Williams et al., of which 74% of NAFLD patients were diabetic. Our study also showed that >50% of subjects were recently diagnosed to have diabetes mellitus, while 26% had diabetes mellitus for >10 years of duration. In the subgroup of NAFLD, additional comorbidities like hypothyroidism and dyslipidemia were noted in 26% and 41%, respectively.
In this study, the subjects who had F1 fibrosis on liver biopsy had a mean fibroscan value of 11.8 Kpa, which fits the norms of F3 fibrosis, which is an overestimation of the fibrosis score. Also that in patients with F2 fibrosis on liver biopsy, the mean fibroscan value is 16.96 Kpa and among the patients with F3 fibrosis, the mean fibroscan value is 21.9 Kpa, which is again an overestimation of the fibrosis score.
Hence, in this study on the NAFLD subgroup of patients, fibroscan had a high accuracy in detecting advanced fibrosis and cirrhosis, which is similar to a study conducted by Gómez-Domínguez et al. In addition, fibroscan has superior performance to other noninvasive biochemical tests in diagnosing advanced fibrosis and cirrhosis.
In a study conducted by Pathik et al., 110 patients who underwent liver biopsy had median fibroscan values for stages 1, 2, 3, and 4 of 8, 9.1, 12, and 20 Kpa respectively. These values were not in agreement with our study.
According to meta-analysis of nine studies conducted by Talwalkar et al., the pooled estimates of sensitivity and specificity were 87% and 91% respectively for cirrhosis and 70% and 84% respectively for F2 or higher disease. Similar levels of accuracy and reproducibility were observed in 50 pediatric NAFLD patients in Italy. In our study, 30 patients had F3 or higher fibrosis, stating that the specificity was higher in the later stages of fibrosis.
Our study revealed that in the subgroup of patients with F1, F2, F3 fibrosis on biopsy, the mean fibroscan values are 11.84 ± 9.23, 16.98 ± 18.85, 33.41 ± 17.39, respectively, which overestimates the fibrosis score. For F4 fibrosis on biopsy, the mean fibroscan value was 33.41 ± 17.39, which is in concordance with liver biopsy.
This observational study of patients with different stages of NAFLD on liver biopsy indicates that fibroscan has more accuracy in detecting F4 fibrosis, while it is more specific but less sensitive in predicting the early stages of NAFLD.
Liver stiffness measurement (LSM) has been shown to be spuriously increased in patients with acute hepatitis and extrahepatic cholestasis, indicating that the stiffness of the liver is not attributable to fibrosis alone. One unique feature of NAFLD patients is the accumulation of subcutaneous, prehepatic, and hepatic fat. Fat accumulation might affect the LSM, and this is of clinical significance. In patients with chronic hepatitis C, hepatic steatosis does not appear to influence LSM.
One possible explanation of this phenomenon is that the distribution of fibrous tissue may be less even in NAFLD patients. In a study of 41 subjects undergoing right lobe and left lobe liver biopsies during bariatric surgery, the kappa coefficient for fibrosis staging was only 0.53. Our study might suggest that, when a noninvasive test disagrees with histological results, the latter may be inaccurate.
| Conclusion|| |
The adoption of Fibroscan could be an alternative to liver biopsy in some patients, as the prevalence of NAFLD is increasing, this approach would be cost-saving. Conversely, the positive predictive value of fibroscan and other noninvasive tests to diagnose advanced fibrosis in NAFLD patients remains modest. Therefore, the main value of these tests is to exclude advanced fibrosis as screening tests.
The limitations of our study are:
- Small sample size
- It is an observational study
- Only medium probe was used irrespective of the BMI of the patients.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]