Use of magnetic resonance elastography for assessing liver functional reserve: A clinical study

Abstract

Aim: To investigate the value of magnetic resonance elastography (MRE) with regard to assessing liver functional reserve.

Methods: Data from inpatients diagnosed with a liver tumor at an interventional radiology department from July 2013 to June 2014 were analyzed. A 3.0 Tesla magnetic resonance unit was used to scan 32 patients with confirmed diagnoses of hepatocellular carcinoma (HCC); an MRE sequence was added to the protocol, and the data were reconstructed and analyzed by two attending radiologists. Regions of interest were identified in different slices of the non-tumor liver parenchyma to measure average stiffness. In addition, the indocyanine green (ICG) test was performed no more than 1 wk before or after the magnetic resonance examination for all 32 patients; the ICG retention rate at 15 min (ICGR-15) and the ICG plasma clearance rate (ICG-K) were recorded. Correlational analyses were performed between the liver stiffness values and the ICGR-15 as well as between the liver stiffness values and the ICG-K.

Results: Magnetic resonance imaging, including an MRE sequence and the ICG test, was performed successfully in all 32 enrolled patients. None of the patients developed complications. The mean ± SD of the elasticity values measured by the two attending radiologists were 4.7 ± 2.2 kPa and 4.7 ± 2.1 kPa, respectively. The average liver stiffness value of the non-tumor parenchyma measured using MRE in HCC patients was 4.7 ± 2.2 kPa. The average ICGR-15 was 0.089 ± 0.077, and the average ICG-K was 0.19 ± 0.07. We found that the liver stiffness value of the non-tumor parenchyma was significantly and positively related to the ICGR-15 (r = 0.746, P < 0.01) as well as significantly and negatively related to the ICG-K (r = -0.599, P < 0.01). The ICGR-15 was significantly and negatively related to the ICG-K (r = -0.852, P < 0.01).

Conclusion: MRE is accurate and non-invasive; furthermore, it can be used to effectively assess the liver functional reserve of HCC patients.

Keywords: Hepatocellular carcinoma; Indocyanine green clearance test; Liver fibrosis; Liver functional reserve; Magnetic resonance elastography.

Figure 1

Distribution of the correlations between the non-tumor liver stiffness values and the indocyanine green retention rate at 15 min (A) or the indocyanine green plasma clearance rate (B).

Figure 2

Liver stiffness with different degrees of fibrosis measured using magnetic resonance elastography and its relevant indocyanine green retention rate at 15 min and indocyanine green plasma clearance rate. A-C: LS, 2.9 kPa; ICGR-15, 0.003; ICG-K, 0.398; D-F: LS, 4.4 kPa; ICGR-15, 0.057; ICG-K, 0.191; G-I: LS, 5.1 kPa; ICGR-15, 0.083; ICG-K, 0.166; J-L: LS, 10 kPa; ICGR-15, 0.252; ICG-K, 0.092. ICGR-15: Indocyanine green retention rate at 15 min; ICG-K: Indocyanine green plasma clearance rate; LS: Liver stiffness.