[Sonographic course of alcoholic fatty liver by interobserver and digital evaluation of liver echogenicity]

The reversibility of alcoholic fatty liver is well-known. The present study aims to investigate whether sonographic controls can document this reversibility under abstinence therapy with respect to inter-observer variability.

59 male patients with alcohol dependency were examined by ultrasound at the beginning and the end of a long-term in-patient withdrawal therapy. Fatty liver was graded qualitatively (no, slight, moderate and severe fatty liver). The sonographic liver sections were registered digitally per examination and were subsequently evaluated by means of the PC by two independent experts. Additionally, a digital texture analysis of representative hepatic and renal regions was performed. The pixel intensity ratio of liver and kidney was used as a measure of liver echogenicity.

In the ultrasound examination, the 59 patients had the following severity grade of fatty liver initially: 18 (31 %) severe, 19 (32 %) moderate, 22 (37 %) slight. 37 patients (63 %) showed sonographically an improvement of the initial severity grade within 79 +/- 26 days (p < 0.0001, 95 % confidence interval: 50 - 74 %). The evaluation by the independent experts revealed 47 and 54 % improvement, respectively. The overall degree of agreement between the 3 ratings concerning grading and course was high (intraclass coefficient = 0.896). However, there was a marked deviation between the several grading levels (agreement 15 - 86 %). The categorical differentiation between no/slight versus moderate/severe fatty liver revealed an agreement of between 81 and 91 %. The mean pixel intensity ratio showed an improvement of 17 % (p < 0.0001).

After 3 months abstinence an improvement of alcoholic fatty liver can be consistently documented in about 50 % of the cases by sonography. The interobserver variability on differentiating no/slight versus moderate/severe fatty liver was low. The digital texture analysis confirmed the range of reversibility and could play a role in quantifying the sonographic degree of fatty infiltration.