Zusammenfassung
Einleitung: Die Reversibilität der alkoholischen Fettleber ist seit langem bekannt. Ziel der vorliegenden Untersuchung war, ob deren Rückbildung im Rahmen einer stationären Entwöhnungstherapie sonografisch nachvollziehbar dokumentiert werden kann. Patienten und Methodik: 59 männliche Patienten mit Alkoholabhängigkeit wurden zu Beginn und Ende einer stationären Entwöhnungstherapie sonografisch untersucht. Die Graduierung der Fettleber erfolgte qualitativ (keine, leichte, mittelschwere oder ausgeprägte Fettleber). Die sonografischen Bilder wurden digital gespeichert und von zwei unabhängigen Gutachtern am PC nachbeurteilt. Ergänzend wurde an repräsentativen Regionen der Leber und Niere eine digitale Texturanalyse durchgeführt. Das Pixelintensitätsverhältnis von Leber und Niere wurde als Maß für die Echogenität der Leber bestimmt. Ergebnisse: Folgende Schweregrade der Fettleber wurden bei Studienbeginn dokumentiert: Ausgeprägt n = 18 (31 %), mittelschwer n = 19 (32 %), leichtgradig n = 22 (37 %). Insgesamt konnte bei 37 Patienten (63 %) innerhalb von 79 ± 26 Tagen sonografisch eine Besserung des Initialbefundes dokumentiert werden (p ≤ 0,0001; 95 % Konfidenzintervall: 50 - 74 %). Die Fremdbegutachtungen ergaben Besserungsraten von 47 bzw. 54 %. Der Grad der Übereinstimmung zwischen den drei Ratings bezüglich Schweregrad und Verlauf war hoch (Intraclasskoeffizient = 0,896) bei deutlichen Abweichungen zwischen den einzelnen Schweregraden (Übereinstimmung 15 - 86 %). Die Abgrenzung keine/leichte versus mittelgradige/schwere Fettleber zeigte jedoch Übereinstimmungen von 81 bis 91 %. Die Texturanalyse ergab im Verlauf einen Abfall des Pixelintensitätsverhältnisses von 17 % (p ≤ 0,0001). Schlussfolgerungen: In einem Zeitfenster von 3 Monaten Alkoholkarenz zeigt sich in 50 % der Fälle eine sonografisch nachvollziehbare Besserung der alkoholischen Fettleber. Die Interoberservervariabilität bei der Unterscheidung: Keine/leichte versus mittelgradige/schwere Fettleber ist gering. Die digitale Texturanalyse des B-Bildes bestätigt die Verlaufsbeurteilung und könnte künftig einen Beitrag zur Quantifizierung des sonografischen Verfettungsgrades leisten.
Abstract
Background: 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. Methods: 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. Results: 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). Conclusions: 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.
Schlüsselwörter
Alkoholische Fettleber - Steatohepatitis - Ultraschall - Digitale Texturanalyse
Key words
liver steatosis - steatohepatitis - ultrasound - texture analysis
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Dr. Benjamin Simonis
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