“Normal” Liver Stiffness Measure (LSM) Values Are Higher in Both Lean and Obese Individuals: A Population-Based Study From a Developing Country

Abstract

The liver stiffness measure (LSM) needs to be explored in ethnically and anthropometrically diverse healthy subjects (to derive an acceptable normal range) and also in patients with liver disease. In view of this objective, LSM was performed by transient elastography (TE) using FibroScan in 437 healthy subjects with normal alanine aminotransferase (ALT) levels, recruited from a free‐living population of the Birbhum Population Project (BIRPOP; http://www.shds.in), a Health and Demographic Surveillance System (HDSS), and from 274 patients with liver disease attending the Hepatology Clinic of the School of Digestive and Liver Diseases (SDLD; Institute of Post Graduate Medical Education & Research [IPGME&R], Kolkata, India) including 188 with nonalcoholic fatty liver disease (NAFLD) and 86 with chronic hepatitis of viral and other etiologies. Liver biopsy was performed in 125 patients. The range of normal values for LSM, defined by 5th and 95th percentile values in healthy subjects, was 3.2 and 8.5 kPa, respectively. Healthy subjects with a lower body mass index (BMI; < <18.5 kg/m2) had a higher LSM compared with subjects who had a normal BMI; this LSM value was comparable to that of obese subjects (6.05 ± 1.78 versus 5.51 ± 1.59 and 6.60 ± 1.21, P = 0.016 and 0.349, respectively). Liver disease patients without histologic fibrosis had significantly higher LSM values compared with healthy subjects (7.52 ± 5.49 versus 5.63 ± 1.64, P < 0.001). Among the histologic variables, stage of fibrosis was the only predictor for LSM. LSM did not correlate with inflammatory activity and ALT in both NAFLD and chronic hepatitis groups. Conclusion: LSM varies between 3.2 and 8.5 kPa in healthy subjects of South Asian origin. Both lean and obese healthy subjects have higher LSM values compared with subjects with normal BMI. Liver stiffness begins to increase even before fibrosis appears in patients with liver disease. (Hepatology 2012)

Assessment of renal allograft fibrosis by transient elastography

“…KS of a normal human allograft was comparable to renal stiffness in 10-week-old landrace pigs without tubulointerstitial fibrosis and corresponded very well to previously published renal allograft stiffness of 32.7 kPa [17]. Thus, the regular KS even exceeds the stiffness of an advanced liver cirrhosis >20 kPa which is most likely because of the higher abundance of connective tissues and vascularization in kidneys under physiological conditions [25][26][27]. Considering the upper detection limit of the Fibroscan device (75 kPa), only a small measuring range from 30 to 75 kPa remains for the kidneys [8].…”

“…Our study has identified the following major confounders: SCD, BMI, missing intercostal fixation, fluid accumulation, variation of the measuring angle, and small cortical parenchyma with heterogeneous calyxes. The recent introduction of the more powerful XL probe has drastically improved stiffness measurements of livers [28] which had similar confounding factors namely in obese patients [25] or ascites [29]. Unfortunately, the XL probe cannot be used in kidneys because of the small and heterogenous cortex parenchyma.…”

WFUMB Guidelines and Recommendations for Clinical Use of Ultrasound Elastography: Part 3: Liver

“…suggest that in healthy individuals, undernutrition and leanness (lower BMI), increase liver stiffness values in a similar way to obesity, providing a U-shaped distribution of normal liver stiffness values (Das et al 2012).…”

Measurement of real-time tissue elastography in a phantom model and comparison with transient elastography in pediatric patients with liver diseases

“…In our patients, 61.5% demonstrated higher values than the upper limit of normal. Lesion 1 in the phantom model was slightly higher than the upper limit of normal values; background and lesions 2-4 represent high kPa values, expressing severe fibrosis or liver cirrhosis in adult patients (11,(24)(25)(26). However, the gradation of elastography methods in children has been missing in the literature, so the lower or higher values in TE should be interpreted with great caution in pediatric patients.…”

“…Liver stiffness measures between 2.5 kPa and 75 kPa. There have been several studies in adults to define the normal values of TE (24)(25)(26). Engelmann et al (9) defined normal values for the pediatric age group.…”