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

Abstract

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, ρ = 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.

Assessment of hepatic fibrosis and inflammation with look-locker T1 mapping and magnetic resonance elastography with histopathology as reference standard

“…The lower diagnostic performance of T1 mapping in our study may be explained by the overlap of T1 values especially between lower stages of fibrosis. Similar overlaps in T1 values between patients without and with advanced hepatic fibrosis have been reported recently [13,14].…”

“…In our study, the T1 relaxation times in patients without fibrosis (856.3 ± 128.7 ms) are within the range of published numbers. Reported T1 values of normal liver at 3.0 Tesla ranged between 809 ± 71 ms and 941 ± 136 ms [13,24,25].…”

“…An advantage of T1 mapping is its robustness in patients with high BMI or ascites [17], and it does not need any additional hardware. T1 relaxation times may also be influenced by hepatic inflammation as shown a recent study on patients with acute liver disease [13].…”

“…Exploring alternative, reproducible, cross-sectional imaging methods, recent studies proposed MR relaxometry with T1 mapping as an alternative method to assess hepatic fibrosis [11][12][13][14]. The T1 relaxation time of tissue is influenced by the molecular environment of water molecules in the tissue.…”

Comparison of Hepatic Tissue Characterization between T1-Mapping and Non-Contrast Computed Tomography

“…In addition, cardiac tissue characterization by T1-mapping provides novel insights into pathological alterations within the myocardium [ 10 , 11 ]. Thus far, only few studies report on the use of T1-mapping in liver MR scans but show promising results [ 12 , 13 , 14 ]. On standard cardiac T1-maps ( Figure 1 ), liver tissue is also assessable but so far has not been used to study hepatic T1-times.…”