Fatty liver in obesity: Relation to Doppler Perfusion Index measurement ofthe liver

Background: The correlation of clinical and laboratory findings with variou s imaging techniques in obese patients is difficult. Colour duplex Doppler is of particularly limited value in fat individuals. The Doppler Perfusion Index (DPT) measures the ratio of hepatic arterial to total liver blood flo w and seems to be more accurate in the study of hepatic hemodynamics. The a im of the present study was to investigate the clinical use of DPI measurem ent of the liver in obesity. Methods: In the present prospective, open stud y we evaluated the DPI in 41 obese patients (body mass index (BMI) > 30 kg/ m(2)) and 18 volunteers with normal or slightly increased weight. Thirty pa tients of the study group underwent liver biopsy during bariatric surgery. In these patients liver histology was assessed and age, BMI, waist to hip r atio (WHR), DPI, liver function tests and serum triglycerides were measured . Results: Obese patients had significantly (P = 0.0036) higher DPI values (0.25 +/- 0.138) than the healthy volunteers (0.15 +/- 0.04). Multivariate analysis revealed that grade of fatty liver in the study group was inversel y associated with DPI and positively depended on serum triglyceride and asp artate aminotransferase (ASAT) levels (fatty liver index = 1.03 x ASAT (IU/ l) + 0.152 x triglyceride (mg%) - 49.75*DPI, with P < 0.0001 and r(2) = 0.8 0). Conclusion: Grade of fatty liver in obese patients may be predicted fro m DPI, serum triglyceride and AST levels. The proposed index may be useful as a non-invasive diagnostic tool during the follow-up of patients with obe sity-related fatty Liver.