Noninvasive liver steatosis quantification using MRI techniques combined with blood markers

To evaluate the accuracy of different techniques of MRI steatosis quantification, based on histological grading and quantification of liver steatosis.

Twenty-three patients (21 with nonalcoholic fatty liver disease and two controls) were included. Steatosis was evaluated in liver specimens using histological grading (five grades) and steatosis area (% of liver surface) was computed using an inhouse automated image analysis. The following five MRI quantification techniques were performed: two-point Dixon, three-point Dixon, DUAL, spin echo method and a new technique called multi-echo gradient-echo (MFGRE). Interobserver (two observers) and intersite (three different liver sites) agreements were evaluated for the two best-performing methods.

Steatosis area was correlated with steatosis grade: Rs (Spearman coefficient) = 0.82, P value of less than 0.001. The steatosis area was significantly different between S0-S2 and S3-S4 grades: 4.2 + or - 2.4 versus 16.4 + or - 8.9% (P< 0.001). Correlations between the MRI techniques and steatosis area (or grading) were: MFGRE, Rs = 0.72 (0.78); spin echo method, Rs = 0.72 (0.76); DUAL, Rs =0.71 (0.76); two-point Dixon, Rs = 0.71 (0.75); three-point Dixon, Rs = 0.67 (0.77). Interobserver (Ric = 0.99) and intersite (Ric = 0.97) agreements were excellent for the liver steatosis measurement by MFGRE. The noninvasive diagnosis of the steatosis area was improved by adding blood markers like ALT and triglycerides to MFGRE (aR2: 0.805).

MRI, and in particular the MFGRE method, provides accurate and automatic quantification for the noninvasive evaluation of liver steatosis, either as a single measurement or in combination with blood variables.