Multiparametric MRI combined with liver volume for quantitative evaluation of liver function in patients with cirrhosis

PURPOSEWe aimed to establish a liver function evaluation model by combining multiparametric magnetic resonance imaging (MRI) with liver volume (LV) and further verify the effectiveness of the model to evaluate liver function.METHODSThis retrospective study included 101 consecutive cirrhosis patients (69 cases for modeling group and 32 cases for validation group) who underwent gadoxetic acid-enhanced MRI. Five signal intensity parameters were obtained by measuring the signal intensities of the liver, spleen, and erector spinae before and 20 minutes after gadoxetic acid disodium enhancement. The diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were obtained from intravoxel incoherent motion diffusion-weighted imaging. The LV parameters (V_liver, V_spleen, and V_liver/V_spleen) were obtained using 3-dimensional image generation software. The most effective parameter was selected from each of the 3 methods, and a multivariate regression model for liver function evaluation was established and validated.RESULTSIn the modeling group, relative enhancement (RE), D*, and V_liver/V_spleen showed significant differences among the different liver function groups (P < .001). Receiver operating characteristic analysis showed that these parameters had the highest area under the curve (AUC) values for distinguishing Child-Pugh A from Child-Pugh B and C groups (0.917, 0.929, and 0.885, respectively). The following liver function model was obtained by multivariate regression analysis: F(x) = 3.96 − 1.243 (RE) − 0.034 (D*) − 0.080 (V_liver/V_spleen) (R² = 0.811, P < .001). In the patients with cirrhosis, the F(x) of Child-Pugh A, B, and C were 1.16 ± 0.44, 1.95 ± 0.29, and 2.79 ± 0.38, respectively. In the validation group, the AUC for F(x) to distinguish Child-Pugh A from Child-Pugh B and C was 0.973.CONCLUSIONCombining multiparametric MRI with LV effectively distinguished patients with different Child-Pugh grades. This model could hence be useful as a novel radiological marker to estimate the liver function.

Main points

• Among the parameters generated by gadoxetic acid disodium-enhanced magnetic resonance imaging (MRI), intravoxel incoherent motion, and liver volume, the relative enhancement (RE), pseudo-diffusion coefficient (D*), and liver-spleen volume ratio (V_liver/V_spleen) displayed the best liver function classification performance.
• The model F(x) combining multiparametric MRI with liver volume showed an area under the curve of 0.973 in distinguishing Child-Pugh A from Child-Pugh B and C. The sensitivity and specificity were 97.6% and 90.9%, respectively.
• The model integrates the functional and morphological information of the liver. It is useful for quantitative liver function evaluation and is expected to be used for preoperative liver function evaluation.

Liver cirrhosis is a pathological stage characterized by diffuse fibrosis of the liver, formation of pseudo-lobules, and blood vessel proliferation in the liver.¹ Liver function assessment is the main factor affecting the prognosis of patients with liver cirrhosis, and the assessment of preoperative and residual liver function is extremely important for patients with liver cancer.² Moreover, liver function is unevenly distributed in the liver parenchyma and varies between different lobes and segments in cirrhosis.³ The liver morphology changes in different stages of cirrhosis. This change is partly derived from changes in the volume and number of liver parenchymal cells. However, clinical methods for assessing liver function focused on clinical symptoms, biochemical blood parameters, and lack of evaluation of liver morphology.^4-6Magnetic resonance imaging (MRI) can provide morphological and functional information about the liver. Gadoxetic acid disodium (Gd-EOB-DTPA) is a liver-targeting MRI contrast agent which can be specifically ingested by normal hepatocytes.⁷ Images of hepatobiliary phase could accurately assess liver volume (LV) which is another important clinical index for liver function.⁸ Liver function is impaired and the number of hepatocytes with normal Gd-EOB-DTPA uptake is reduced in cirrhosis. At the same time, the uptake of Gd-EOB-DTPA by hepatocytes is reduced due to the proliferation of fibrous stroma and the reduction of organic anion transporter polypeptide (OATP) expression. Consequently, the liver signal decreases during the hepatobiliary phase.⁹ During the progression of cirrhosis, the increased intrahepatic connective tissue reduces hepatic blood flow and diffusion capacity, leading to hepatocyte degeneration, inflammatory infiltration, and fibrosis. All of this leads to changes in liver tissue structure and perfusion. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) can simultaneously obtain information on liver perfusion and water diffusion. The diffusion coefficient (D) value has high sensitivity and specificity in detecting liver fibrosis.¹⁰ Multiparametric imaging combining conventional techniques could enable a comprehensive examination of the liver.¹¹In view of the potential value of LV and multiparametric MRI in liver function assessment, this study aims to establish a liver function evaluation model by combining multiparametric MRI with LV and further verify the effectiveness of the model to evaluate liver function.