Evaluation of liver fibrosis and cirrhosis on the basis of quantitative T1 mapping: Are acute inflammation, age and liver volume confounding factors?

Purpose: To evaluate potential confounding factors in the quantitative assessment of liver fibrosis and cirrhosis using T1 relaxation times. Methods: The study population is based on a radiology-information-system database search for abdominal MRI performed from July 2018 to April 2019 at our institution. After applying exclusion criteria 200 (59 +/- 16 yrs) remaining patients were retrospectively included. 93 patients were defined as liver-healthy, 40 patients without known fibrosis or cirrhosis, and 67 subjects had a clinically or biopsy-proven liver fibrosis or cirrhosis. T1 mapping was performed using a slice based look-locker approach. A ROI based analysis of the left and the right liver was performed. Fat fraction, R2*, liver volume, laboratory parameters, sex, and age were evaluated as potential confounding factors. Results: T1 values were significantly lower in healthy subjects without known fibrotic changes (1.5 T MRI: 575 +/- 56 ms; 3 T MRI: 857 +/- 128 ms) compared to patients with acute liver disease (1.5 T MRI: 657 +/- 73 ms, p < 0.0001; 3 T MRI: 952 +/- 37 ms, p = 0.028) or known fibrosis or cirrhosis (1.5 T MRI: 644 +/- 83 ms, p < 0.0001; 3 T MRI: 995 +/- 150 ms, p = 0.018). T1 values correlated moderately with the Child-Pugh stage at 1.5 T (p = 0.01, rho = 0.35). Conclusion: T1 mapping is a capable predictor for detection of liver fibrosis and cirrhosis. Especially age is not a confounding factor and, hence, age-independent thresholds can be defined. Acute liver diseases are confounding factors and should be ruled out before employing T1-relaxometry based thresholds to screen for patients with liver fibrosis or cirrhosis.