Acoustic radiation force imaging sonoelastography for noninvasive staging of liver fibrosis

Abstract

Aim: To investigate the diagnostic accuracy of acoustic radiation force impulse (ARFI) imaging as a noninvasive method for the assessment of liver fibrosis in chronic hepatitis C (CHC) patients.

Methods: We performed a prospective blind comparison of ARFI elastography, APRI index and FibroMax in a consecutive series of patients who underwent liver biopsy for CHC in University Hospital Bucharest. Histopathological staging of liver fibrosis according to the METAVIR scoring system served as the reference. A total of 74 patients underwent ARFI elastography, APRI index, FibroMax and successful liver biopsy.

Results: The noninvasive tests had a good correlation with the liver biopsy results. The most powerful test in predicting fibrosis was ARFI elastography. The diagnostic accuracy of ARFI elastography, expressed as area under receiver operating characteristic curve (AUROC) had a validity of 90.2% (95% CI AUROC = 0.831-0.972, P < 0.001) for the diagnosis of significant fibrosis (F >or= 2). ARFI sonoelastography predicted even better F3 or F4 fibrosis (AUROC = 0.993, 95% CI = 0.979-1).

Conclusion: ARFI elastography had very good accuracy for the assessment of liver fibrosis and was superior to other noninvasive methods (APRI Index, FibroMax) for staging liver fibrosis.

Figures

Figure 1

Diagram of patients with liver biopsy for CHC in the University Hospital Bucharest during the 18-mo study period.

Figure 2

Box plot of METAVIR score and ARFI elastography. Top and bottom of boxes represent first and third quartiles, respectively. Length of box represents interquartile range within which 50% of values are located. Thick line through each box represents the median. Error bars mark minimum and maximum values (range). Small circles represent outliers. Skewed data for fibrosis stage 0/1 can be explained by the small number of patients in this group.

Figure 3

ROC curves: elastography predicting ≥ F2 fibrosis, ≥ F3 fibrosis and F4 fibrosis.

Figure 4

Cutoff points for degrees of fibrosis.

Figure 5

Correlation between METAVIR and ARFI elastography. Correlation between METAVIR and ARFI elastography showed that the overlap between stages F1 and F2 fibrosis limits the discriminatory value of the test in this context.