Multiparametric ultrasound evaluation of post-SARS-CoV-2 liver parenchymal changes

To evaluate and quantify changes in the liver parenchyma of patients who have had Covid-19 and provide insight into possible correlations between liver damage and the course and sequelae of Covid-19 infection.  Prospective cross-sectional study enrolled 90 patients: 56 of these had proved Covid-19 disease within a time period of 3-9 months before enrolment and 34 patients were a clinically healthy control group. A thorough clinical history and patient data (BMI, laboratory data) were acquired and all patients underwent a multiparametric ultrasound evaluation of the liver parenchyma, including quantitative elastography measurements of fibrosis, attenuation imaging for steatosis grade and dispersion imaging for liver viscosity. Abdominal magnetic resonance and thoracic computed tomography scans were performed on 76 patients, who were also screened for biochemical markers of liver impairment and inflammation. Covid-19 patients were found to have significantly different fibrosis, steatosis and viscosity scores when compared to the control group (p<0.001), but no direct correlation was observed. Fibrosis scores were higher in Covid-19 patients (F2,F3) vs. the control group (p<0.001). Dispersion measurements were higher in patients who had a thicker subcutaneous fat layer (F=4.7;p=0.035). 33 Covid-19 patients were hospitalized (59%), and more severe disease course was found to have significantly higher US steatosis grade (F= 9.1;p<0.01). US increased liver echogenicity correlated with decreased liver density on CT (r=0,46;p=0,01). Common liver markers (GGT,LDH,ALAT) had a statistically significant correlation (p<0.05) to changes observed by ultrasound in Covid-19 patients, however no such correlations were found in the control group between liver markers and changes in liver CT and MRI. Post SARS-CoV-2 patients had significant parenchymal liver changes – fibrosis, steatosis and viscosity. Increased liver steatosis correlated to a more severe disease course in patients with Covid-19. Multiparametric liver ultrasound may be more specific in evaluating parenchimal liver alterations in Covid-19 patients than MRI or CT.