Published online May 14, 2018. doi: 10.3748/wjg.v24.i18.2024
Peer-review started: March 9, 2018
First decision: March 29, 2018
Revised: April 6, 2018
Accepted: April 15, 2018
Article in press: April 15, 2018
Published online: May 14, 2018
Chronic hepatitis B/C (CHB/C) are both leading causes of liver-related morbidity and mortality and predisposes patients to liver fibrosis, the excessive accumulation of extracellular matrix proteins. As fibrosis progresses, it leads to cirrhosis and even cancer. Early diagnosis and monitoring of liver fibrosis, and intervention with timely and effective treatments, are critical for patients with liver disease. At present, liver biopsy is the gold standard for diagnosis of liver fibrosis. Invasive methods have a risk of bleeding and increased tissue injury, and the repeatability of the examination is poor. Therefore, noninvasive, comprehensive and accurate methods of diagnosing liver fibrosis are required.
Currently, noninvasive methods have been increasingly used, such as serological examination, ultrasound-based elastography, diffusion-weighted imaging, magnetic resonance enterography, and texture analysis. None of these methods can replace the biopsy. T1 mapping via the Look-Locker method is one of the fastest approaches to T1 quantification, and is the most time efficient method for T1 mapping and less affected by magnetic resonance parameters than other methods. We proposed a method based on a simple pharmacokinetic model and ΔR1 values to calculate a hepatocyte fraction (HeF). Furthermore, mismatches between pre- and postcontrast images were observed due to motion and the long gap between scans. To improve accessibility for future clinical use, further development in fast multislice or 3D volume quantitative T1 mapping is needed with liver-specific motion registration.
We aimed to quantitatively assess the level of hepatic fibrosis in hepatitis B and C patients by calculating the HeF and compare the results with traditional T1-enhanced test parameters. In the future, more imaging methods should be compared with HeF, such as magnetic resonance enterography and diffusion-weighted imaging.
One hundred and nine patients were included in the study. Magnetic resonance images were obtained with a gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced 3-Tesla magnetic resonance imaging system, including T1-weighted and Look-Locker sequences for T1 mapping. HeF and relaxation time reduction rate (RE) were calculated for staging hepatic fibrosis. Area under the receiver operating characteristic curve (AUC) was used to compare the diagnostic performance in predicting liver fibrosis between HeF and RE.
We included a total of 73 patients who were deemed eligible for inclusion on histopathological findings. The results of our study indicated that T1 parameters from pre- or postcontrast T1 maps (HeF) and RE had good diagnostic value in the assessment of CHB, CHC and liver fibrosis. HeF and RE both had good diagnostic performance in advanced liver fibrosis and cirrhosis (≥ F3 and F4) (AUC > 0.9). In diagnosis at ≥ F1 and ≥ F2 stages, HeF was better than RE.
This study showed a strong correlation between HeF and liver fibrosis stage in CHB and CHC. The methods use HeF and RE to generate quantitative measurements to distinguish different grades of liver fibrosis, but HeF performed better than RE. This study showed that the T1 mapping-based HeF method is an efficient diagnostic tool for the staging of liver fibrosis.
Due to the limited number of patients included, further studies are needed to assess the performance of the HeF in hepatic fibrosis. More imaging methods should be compared in the field of liver fibrosis diagnosis.