Hepatic Computed Tomography Volumetry for Noninvasive Detection of Hepatic Steatosis and Steatohepatitis in Living Liver Donors

The effect of hepatic steatosis on liver volume determined by proton density fat fraction and deep learning-measured liver volume

OBJECTIVES

We aimed to evaluate the effect of hepatic steatosis (HS) on liver volume and to develop a formula to estimate lean liver volume correcting the HS effect.

METHODS

This retrospective study included healthy adult liver donors who underwent gadoxetic acid-enhanced MRI and proton density fat fraction (PDFF) measurement from 2015 to 2019. The degree of HS was graded at 5% PDFF intervals from grade 0 (no HS; PDFF < 5.5%). Liver volume was measured with hepatobiliary phase MRI using deep learning algorithm, and standard liver volume (SLV) was calculated as the reference lean liver volume. The association between liver volume and SLV ratio with PDFF grades was evaluated using Spearman's correlation (ρ). The effect of PDFF grades on liver volume was evaluated using the multivariable linear regression model.

RESULTS

The study population included 1038 donors (mean age, 31 ± 9 years; 689 men). Mean liver volume to SLV ratio increased according to PDFF grades (ρ = 0.234, p < 0.001). The multivariable analysis indicated that SLV (β = 1.004, p < 0.001) and PDFF grade*SLV (β = 0.044, p < 0.001) independently affected liver volume, suggesting a 4.4% increase in liver volume per one-point increment in the PDFF grade. PDFF-adjusted lean liver volume was estimated using the formula, liver volume/[1.004 + 0.044 × PDFF grade]. The mean estimated lean liver volume to SLV ratio approximated to one for all PDFF grades, with no significant association with PDFF grades (p = 0.851).

CONCLUSION

HS increases liver volume. The formula to estimate lean liver volume may be useful to adjust for the effect of HS on liver volume.

KEY POINTS

• Hepatic steatosis increases liver volume. • The presented formula to estimate lean liver volume using MRI-measured proton density fat fraction and liver volume may be useful to adjust for the effect of hepatic steatosis on measured liver volume.

Noninvasive Estimation of Hepatic Steatosis by Controlled Attenuation Parameter in Living Donor Liver Transplant

OBJECTIVES

Estimation of liver fat among living donor candidates is necessary before living donor liver transplant. This study aimed to investigate the usefulness of the controlled attenuation parameter compared with liver biopsy for pretransplant estimation of hepatic steatosis in living liver donors.

MATERIALS AND METHODS

In this retrospective study, we included all individuals who underwent transient elastography with controlled attenuation parameter and ultrasonography-guided liver biopsy as a part of donor evaluations before living donor liver transplant. Clinical and laboratory data of living donor candidates were reviewed and collected.

RESULTS

Of 49 donor candidates included in this study, 21 (42.9%) had different degrees of hepatic macrosteatosis. Of the 21 donor candidates who had hepatic steatosis in liver biopsy, 13 individuals were diagnosed to have steatosis in transient elastography. Of the 28 donor candidates without hepatic steatosis in liver biopsy, 26 individuals showed no steatosis in transient elastography (odds ratio: 21.12; 95% CI, 3.91- 114.08; P < .001). Controlled attenuation parameter was useful in discriminating presence (P = .001) and grade of hepatic steatosis (P = .009) compared with liver biopsy with good sensitivity and specificity.

CONCLUSIONS

The controlled attenuation parameter is a noninvasive method for detection of hepatic steatosis in living donor candidates and can be used as an adjunct to liver biopsy for screening of living donor candidates before liver transplant.