Browsing by Subject "vibration controlled transient elastography"

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    Hepatic steatosis is highly prevalent but is not correlated with stiffness in autoimmune hepatitis
    (Wolters Kluwer, 2020-10-16) Chalasani, Sai; Mathur, Karan; Shammas, Nicole; Orman, Eric; Vuppalanchi, Raj; Lammert, Craig; Medicine, School of Medicine
    The prevalence and impact of hepatic steatosis among patients with autoimmune hepatitis (AIH) is not well described. We conducted a cross-sectional study to determine the prevalence of hepatic steatosis in AIH patients and examined its relationship with hepatic fibrosis using vibration controlled transient elastography. Liver stiffness measurement (LSM), controlled attenuation parameter (CAP), gender, current age, and body mass index (BMI) were collected from 277 AIH patients. Hepatic steatosis was defined as CAP >263 db/m. The study participants were mostly female (82%) with an average age of 49 years and BMI 29.7 kg/m2. Mean LSM was 12.5 (standard deviation 13.5) kPa and CAP was 244 (standard deviation 63) db/m. The prevalence of coexisting steatosis was 33.2%, and steatosis did not correlate with LSM (r = 0.05, P = .46). In this study, only gender (females with 31% lower LSM on average compared to males, P = .001) and BMI (each unit increase of BMI resulted in a 1.48% increase on average LSM, P = .01) correlated with LSM. Male gender had significant association with increased LSM, after controlling for age, BMI, and CAP (P = .001). This exploratory study using noninvasive vibration controlled transient elastography revealed hepatic steatosis is highly prevalent in patients with AIH but not associated with liver fibrosis.
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    Performance Characteristics of Vibration-Controlled Transient Elastography for Evaluation of Non-Alcoholic Fatty Liver Disease
    (Wiley, 2017) Vuppalanchi, Raj; Siddiqui, Mohammad S.; Van Natta, Mark L.; Hallinan, Erin; Brandman, Danielle; Kowdley, Kris; Neuschwander-Tetri, Brent A.; Loomba, Rohit; Dasarathy, Srinivas; Abdelmalek, Manal; Doo, Edward; Tonascia, James A.; Kleiner, David E.; Sanyal, Arun J.; Chalasani, Naga; Department of Medicine, School of Medicine
    Background: Vibration-controlled transient elastography (VCTE) estimates liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) which are noninvasive assessments of hepatic fibrosis and steatosis respectively. However, prior VCTE studies reported high failure rate in patients with non-alcoholic fatty liver disease (NAFLD). Aim: To examine the performance characteristics of Fibroscan 502 Touch with two probes, medium (M+) and extra-large (XL+), in patients with NAFLD in a multicenter setting. Methods: A total of 1696 exams were attempted in 992 patients (BMI: 33.6 ± 6.5 kg/m2) with histologically confirmed NAFLD. Simultaneous assessment of LSM and CAP was performed using Fibroscan 502 Touch with an automatic probe selection tool. Testing was conducted twice in patients by either a single operator (88%) or two operators (12%). Failure was defined as the inability to obtain a valid examination. An examination was considered unreliable if LSM IQR/median was >30%. Significant disagreement between two readings was defined as greater than >95% limits of agreement between two readings. Results: A total of 1641 examinations yielded valid results with a failure rate of 3.2% (55/1696). The proportion of unreliable scans for LSM was 2.4%. The proportion of unreliable scans with operator experience in the top quartile (≥ 59 procedures) was significantly lower than lower three quarters combined (1.6% vs.4.7%, p=0.01 by Fisher's Exact test). The significant disagreement between first and second readings for LSM and CAP when obtained back to back was 18% and 11% respectively. Conclusion: VCTE for estimation of LSM and CAP can be successfully deployed in a multicenter setting with low failure (3.2%) and high reliability (>95%) rates and high reproducibility.
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    Vibration-controlled Transient Elastography to Assess Fibrosis and Steatosis in Patients With Nonalcoholic Fatty Liver Disease
    (Elsevier, 2018) Siddiqui, Mohammad S.; Vuppalanchi, Raj; Van Natta, Mark L.; Hallinan, Erin; Kowdley, Kris V.; Abdelmalek, Manal; Neuschwander-Tetri, Brent A.; Loomba, Rohit; Dasarathy, Srinivasan; Brandman, Danielle; Doo, Edward; Tonascia, James A.; Kleiner, David E.; Chalasani, Naga; Sanyal, Arun J.; Medicine, School of Medicine
    Background & Aims Vibration-controlled transient elastography (VCTE), which measures liver stiffness, has become an important tool for evaluating patients with nonalcoholic fatty liver disease (NAFLD). We aimed to determine the diagnostic accuracy of VCTE in detection of NAFLD in a multicenter cohort of patients. Methods We performed a prospective study of 393 adults with NAFLD who underwent VCTE within 1 year of liver histology analysis (median time, 49 days; interquartile range, 25–78 days), from July 1, 2014 through July 31, 2017. Liver stiffness measurement (LSM) cutoffs for pairwise fibrosis stage and controlled attenuation parameter (CAP) cutoffs for pairwise steatosis grade were determined using cross-validated area under the receiver operating characteristics curve (AUROC) analyses. Diagnostic statistics were computed at sensitivity fixed at 90% and specificity fixed at 90%. Results LSM identified patients with advanced fibrosis with an AUROC of 0.83 (95% CI, 0.79– 0.87) and patients with cirrhosis with an AUROC of 0.93 (95% CI, 0.90–0.97). At fixed sensitivity, a cutoff LSM of 6.5 kPa excluded advanced fibrosis with a negative predictive value of 0.91; a cut-off LSM of 12.1 kPa excluded cirrhosis with a negative predictive value of 0.99. At fixed specificity, LSM identified patients with advanced fibrosis with a positive predictive 0.71 and patients with cirrhosis with a positive predictive value of 0.41. CAP analysis detected steatosis with an AUROC of 0.76 (95% CI, 0.64–0.87). In contrast, the VCTE was less accurate in distinguishing lower fibrosis stages, higher steatosis grades, or presence of NASH. Conclusion In a prospective study of adults with NAFLD, we found VCTE to accurately distinguish advanced vs earlier stages of fibrosis, using liver histology as the reference standard.