Abstract
BackgroundTo determine the utility of single-contrast-bolus hepatic extracellular volume (ECV) fraction measurement at different time points to detect and quantify hepatic fibrosis.MethodsDifferent grades of liver fibrosis were induced in 23 male Sprague-Dawley rats by carbon-tetrachloride (CCl4) intoxication. In ten control rats, no fibrosis was induced. Native T1 values and ECV fraction were assessed by using quantitative magnetic resonance imaging (MRI) mapping; only one contrast bolus was applied (gadobutrol 0.1 mmol/kg). ECV values were determined 5, 15, and 25 min after injection. Hepatic fibrosis was quantified histologically by Sirius red staining.ResultsFor the 8-week-CCl4 group, the ECV fraction values obtained 5 (23.5 ± 4.8%, mean ± standard deviation), 15 (23.6 ± 4.8%), and 25 min (23.7 ± 4.7%) after injection were constant over time (p = 0.998); constant data 5–25 min after injection were also observed for the 16-week-CCl4 group and controls. Liver ECV after 15 min significantly increased with the severity of fibrosis: 18.0 ± 3.0% (controls) versus 23.6 ± 4.8% (8-week-CCl4) versus 30.5 ± 3.3% (16-week-CCl4) (p < 0.001). ECV values after 5, 15, and 25 min significantly correlated with Sirius red staining (p < 0.001 for all parameters).ConclusionsHepatic ECV obtained using a single-contrast-bolus technique can be measured 5, 15, and 25 min after injection, obtaining constant values over time, each of them being suitable to detect diffuse hepatic fibrosis. In clinical practice, post-contrast T1 relaxation times for liver ECV fraction determination might be obtained at only one time point.
Highlights
To determine the utility of single-contrast-bolus hepatic extracellular volume (ECV) fraction measurement at different time points to detect and quantify hepatic fibrosis
We observed a continuous increase in the percentage of positive staining for Sirius red for the different severities of liver fibrosis (0.1 ± 0.1% in controls versus 3.3 ± 2.6% in 8-week Carbon tetrachloride (CCl4) group versus 25.1 ± 3.2% in 16-week CCl4 group (p < 0.001)
Mean native T1 values increased with different severities of liver fibrosis: 593.3 ± 10.3 ms in controls versus 625.5 ± 38.3 ms in the 8-week CCl4 group versus 645.6 ± 41.0 ms in the 16-week CCl4 group (p = 0.007)
Summary
To determine the utility of single-contrast-bolus hepatic extracellular volume (ECV) fraction measurement at different time points to detect and quantify hepatic fibrosis. The development of liver fibrosis is an unfavourable sign, which is tightly linked to progression of liver disease, portal hypertension and hepatocellular carcinoma [3]. Since the Luetkens et al European Radiology Experimental (2019) 3:22 development of fibrosis increases the risk for progression towards cirrhosis and hepatocellular carcinoma, the presence of fibrosis requires interventions (e.g., life style modifications in non-alcoholic steatohepatitis, alcohol cessation in alcohol-related liver disease, suppression of immune response in autoimmune hepatitis, or antiviral agents in hepatitis C infection [4]). Besides liver biopsy with its known drawbacks such as risk of severe complications and a high intra- and interobserver variability [5], non-invasive techniques such as transient elastography are increasingly preferred in order to grade liver fibrosis. Among other imaging modalities (e.g., dynamic computed tomography and contrast-enhanced ultrasound), contrast-enhanced magnetic resonance imaging (MRI) is the reference standard for liver imaging and exclusion of malignancies such as hepatocellular carcinomas [7]
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