Non-invasive Assessment of Subclinical Renal Parenchymal Changes in Chronic Hepatitis B Virus By T1 Mapping Magnetic Resonance Imaging

BACKGROUND: Renal parenchymal changes are seen in chronic hepatitis B virus (HBV) infection, and its disease diagnosis should be confirmed by renal biopsy, which is an invasive technique. Apparent-T1 mapping magnetic resonance imaging (MRI) is an established imaging technique that assesses subclinical tissue injury without using a contrast agent. AIMS: To investigate the early stage subclinical renal changes without apparent renal dysfunction in patients with chronic HBV infection by renal apparent-T1 mapping MRI. STUDY DESIGN: A cross-sectional study. METHODS: This study included 45 participants with normal kidney function, wherein 25 have biopsy-proven chronic HBV hepatitis and 20 are healthy individuals. Liver and kidney biochemical tests were performed within 1 month before the MRI scan, and the estimated glomerular filtration rate was calculated by diet modification in renal disease formula. Breath-hold, electrocardiogram-gated Modified Look-Locker Imaging sequence was acquired in the coronal plane without contrast agent administration. Apparent-T1 mapping value was measured by manually drawing a region of interest in six points for both kidneys by two observers. Apparent-T1 mapping values were compared between the two groups. RESULTS: The mean apparent-T1 mapping values of the kidneys were significantly higher in patients with chronic HBV infection compared to the control group (1445 ± 129 ms vs. 1306 ± 115 ms, P = 0.003). Inter-class correlation coefficient measurement analysis showed excellent agreement. CONCLUSION: Renal apparent-T1 mapping MRI may help show the early stage of renal parenchymal disease without apparent renal dysfunction in chronic HBV infection.