Evaluation of Sonographic Detected Fatty Livers: Comparison of Multi Parametric MRI with ARFI Elastography; An Initial Experience

Abstract

Background: Even as ultrasound based elastography detects changes in liver stiffness with good accuracy  newer emerging tools using magnetic resonance imaging(MRI) are being evaluated to have a global assessment of Non alcoholic fatty liver disease(NAFLD). This study was designed to compare the role Multiparametric MRI (mpMRI) and ultrasound elastography in the assessment of fatty liver detected on sonogram. Study: 50 consecutive non alcoholic patients with no prior history of chronic liver disease with fatty liver on sonogram had shear wave elastography using acoustic radiation force impulse (SW-ARFI) imaging followed by Mp MRI. The median liver stiffness was assessed on ARFI while liver fat content, iron content along with Mean T1 value of liver determined on MpMRI. The results of   both modalities were statistically analyzed. Results: Out of 50 patients examined with echogenic fatty livers, 30 were males and 20 females with mean age of 42 years. The median liver stiffness on ARFI was 1.37 m/s while median T1   on Mp MRI was 653.8 msec.  MpMRI showed a sensitivity and specificity of 100%, 91% in detection of liver inflammation with AUC of 1.0 with ARFI.  Statistically significant linear relationship was seen between liver iron content and liver fat content in all groups with T1 maps. 3 patients had abnormal high liver iron content with normal liver fat content but had echogenic fatty liver appearance on ultrasound. Conclusion: Mp MRI detects changes in liver stiffness based on T1 estimation of liver parenchyma with high sensitivity and specificity with results comparable with SWI-ARFI.  It has advantage over ARFI being more robust and also estimates liver fat and iron content and can be used a single shot test for comprehensive evaluation of echogenic livers.