Liver and Spleen Stiffness Measurements by Point Shear Wave Elastography via Acoustic Radiation Force Impulse: Intraobserver and Interobserver Variability and Predictors of Variability in a US Population.
OBJECTIVE
Measurements of liver stiffness and spleen stiffness are useful noninvasive ways to assess fibrosis and portal hypertension in patients with chronic liver disease. One method for assessing stiffness is by point shear wave elastography via acoustic radiation force impulse imaging (ARFI). Its advantage is that sites where stiffness is measured are visualized sonographically. However, its reliability has not been well established, and all studies done to date evaluating the use of ARFI in chronic liver disease have been performed outside the United States. We aimed to characterize the intraobserver and interobserver variability of ARFI-measured liver and spleen stiffness.


METHODS
Two hepatologists evaluated unselected hepatology outpatients with ARFI. Exclusions were hepatocellular carcinoma, ascites, a surgical shunt or transjugular intrahepatic portosystemic shunt, portal thrombosis, and cholestatic disease. Each operator obtained 20 measurements from the right liver lobe and spleen. Intraclass correlation coefficients (ICC) were calculated.


RESULTS
A total of 177 patients were included: median age, 61 years; 85% male; and 43% obese. Intraobserver ICCs were the same for both observers for liver stiffness (0.89; 95% confidence interval [CI], 0.85-0.92) and spleen stiffness (0.72; 95% CI, 0.61-0.80). Interobserver agreement was excellent for liver stiffness (ICC, 0.85; 95% CI, 0.76-0.90) but not as good for spleen stiffness (ICC, 0.73; 95% CI, 0.60-0.83). A body mass index of 30 kg/m2or greater, waist circumference of greater than 105 cm, and skin-to-capsule distance of 2 cm or greater negatively affected the ICC for liver stiffness; small spleen size negatively affected the ICC for spleen stiffness.


CONCLUSIONS
To our knowledge, this article is the first report of ARFI findings in a US population with chronic liver disease. Liver stiffness reproducibility was excellent, particularly in nonobese patients. Spleen stiffness reproducibility was excellent in those with larger spleens and therefore may be most useful in patients with cirrhosis and portal hypertension.
Digestive Diseases Section, Yale School of Medicine, New Haven, Connecticut USA.
Maya
M
Balakrishnan
Digestive Diseases Section, VA Connecticut Healthcare System, West Haven, Connecticut USA.
Fernanda
F
Souza
Digestive Diseases Section, VA Connecticut Healthcare System, West Haven, Connecticut USA.
Carolina
C
Muñoz
Digestive Diseases Section, VA Connecticut Healthcare System, West Haven, Connecticut USA.
Salvador
S
Augustin
Digestive Diseases Section, Yale School of Medicine, New Haven, Connecticut USA.|Digestive Diseases Section, VA Connecticut Healthcare System, West Haven, Connecticut USA.
Nicole
N
Loo
Yale Center for Analytical Sciences, Yale University School of Public Health, New Haven, Connecticut.
Yanhong
Y
Deng
Yale Center for Analytical Sciences, Yale University School of Public Health, New Haven, Connecticut.
Maria
M
Ciarleglio
Digestive Diseases Section, Yale School of Medicine, New Haven, Connecticut USA guadalupe.garcia-tsao@yale.edu.|Digestive Diseases Section, VA Connecticut Healthcare System, West Haven, Connecticut USA guadalupe.garcia-tsao@yale.edu.
Guadalupe
G
Garcia-Tsao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D013154:Spleen / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014481:United States
acoustic radiation force impulse; gastrointestinal ultrasound; liver stiffness; point shear wave elastography; spleen stiffness; ultrasound-based elastography