Purpose: To assess the accuracy of the T1 relaxation time index on gadoxetic acid-enhanced magnetic resonance imaging (MRI) for staging liver fibrosis in chronic hepatitis B (CHB), in comparison and combination with the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4).
Materials and methods: A retrospective study of gadoxetic acid-enhanced T1 mapping and serum biochemical tests was performed on 126 CHB patients who underwent gadoxetic acid-enhanced 1.5T MRI, and the histological score used as the gold standard. The reduction rate of T1 relaxation time before and 20 minutes after gadoxetic acid injection (ΔT1 , ΔR1%), the contrast uptake rate (KHep ), APRI, and FIB-4 were calculated. The diagnostic efficacy of ΔT1 , ΔR1%, KHep , APRI, and FIB-4 for predicting stage 2 or greater (≥S2), stage 3 or greater (≥S3), and stage 4 (S4) was compared.
Results: ΔT1 (r = -0.513, P < 0.001), ΔR1% (r = -0.626, P < 0.001), KHep (r = -0.527, P < 0.001), APRI (r = 0.519, P < 0.001), and FIB-4 (r = 0.476, P < 0.001) correlated significantly with fibrosis stages. Areas under the curves (AUCs) of ΔR1% for detecting ≥S2, ≥S3, and S4 were 0.849, 0.827, and 0.809, which were greater than that of APRI (0.763, 0.745, 0.787) and FIB-4 (0.727, 0.738, 0.772), but significant difference was found only in discriminating ≥S2 between ΔR1% and FIB-4 (P = 0.027). The combination of all five indices performed best, with AUC, sensitivity, and specificity of 0.860, 87.21%, and 72.50% for diagnosing ≥S2, 0.878, 82.81%, and 85.48% for ≥S3, and 0.867, 80.00%, and 83.95% for S4.
Conclusion: The gadoxetic acid-enhanced T1 relaxation time index appears to be superior to APRI and FIB-4 for predicting hepatic fibrosis. The combined use of gadoxetic acid-enhanced T1 mapping, APRI, and FIB-4 may be more reliable for staging liver fibrosis in CHB.
Level of evidence: 4 J. Magn. Reson. Imaging 2017;45:1186-1194.
Keywords: T1 relaxation time; chronic hepatitis B; gadoxetic acid; liver fibrosis; magnetic resonance imaging; serum markers.
© 2016 International Society for Magnetic Resonance in Medicine.