Contrast Enhanced Ultrasound (CEUS) Characterization of Grey-scale Sonographic Indeterminate Focal Liver Lesions in Pediatric Practice

Abstract

Purpose: To determine the usefulness of contrast-enhanced ultrasound (CEUS) in characterizing grey-scale sonographic indeterminate focal liver lesions (FLL) in pediatric practice.

Materials and Methods: Local Ethics Board approval waiver was attained. Consent for CEUS examinations was acquired from parents. Forty-four children referred for CEUS assessment of grey-scale sonographic indeterminate FLL over a 5-year period underwent standard multiphase CEUS performed by experienced operators. A phospholipid microbubble agent was used and low mechanical index ultrasound imaging techniques employed. Interpretation by consensus of the CEUS examination was compared to consensus interpretation of other imaging and to histology. Follow-up imaging was used to confirm stability of benign abnormalities. Any contrast reactions were recorded.

Results: The CEUS examination interpretation agreed with reference imaging in 29/34 (85.3 %) of cases. In discordant cases, reference imaging showed no abnormality (n = 5), with fatty change (n = 4) and regenerating nodules (n = 1) on CEUS and follow-up sonography. Where reference imaging was not performed (n = 10), histology (n = 7) or follow-up sonography (n = 3) confirmed the diagnosis. In one discordant case, all imaging modalities showed concordance identifying a malignant lesion; however histology demonstrated a benign hepatocellular adenoma. The specificity was 98.0 % (95 % CI; 86 – 100 %) and the negative predictive value was 100 %. No adverse effects to the contrast material were noted.

Conclusion: These findings demonstrate the usefulness of CEUS in characterizing indeterminate grey-scale sonography FLL in pediatric patients with the potential to reduce exposure to ionizing radiation.

Zusammenfassung

Ziel: Ermittlung des Nutzens des kontrastverstärkten Ultraschalls (CEUS) zur Charakterisierung von von im Graustufen-Ultraschall nicht-bestimmbaren fokalen Leberläsionen in der pädiatrischen Praxis.

Methoden: Die Zustimmung der örtlichen Ethikkommission wurde erteilt und die Einverständniserklärung zur CEUS-Untersuchung von den Eltern eingeholt. An der CEUS-Bewertung der sonografisch nicht-bestimmbaren FLLs nahmen 44 Kinder über einen Zeitraum von 5 Jahren teil, die sich einem standardisierten Multiphasen-CEUS unterzogen, der von erfahrenen Untersuchern durchgeführt wurde. Hierfür wurde ein Phospholipid-Mikrobläschen Kontrastmittel verabreicht und eine sonografische Technik mit niedrigem mechanischem Index verwendet. Die Auswertung des Konsensus der CEUS-Untersuchung wurde mit der Konsensusauswertung anderer darstellender Verfahren und der histologischen Untersuchung verglichen. Eine Kontrolluntersuchung wurde veranlasst, um die Konstanz der Befunde gutartiger Läsionen von gutartigen Veränderungen zu bestätigen. Alle Kontrastmittelreaktionen wurden erfasst.

Ergebnisse: Die Auswertung der CEUS-Untersuchungen stimmte in 29/34 (85,3 %) der Fälle mit den Referenzmethoden überein. In widersprüchlichen Fällen zeigte die Referenzmethode keine Anomalien (n = 5), die CEUS und die Kontrolluntersuchung jedoch 4 Fettverteilungsstörungen und einen Regenerationsknoten. In Fällen, in denen kein Referenzverfahren gemacht wurde (n = 10) bestätigten Histologie (n = 7) oder Verlaufssonografie (n = 3) die Diagnose. In 2 Fällen zeigten die bildgebenden Verfahren übereinstimmend eine maligne Läsion; die Histologie ergab ein hepatozelluläres Adenom. Die Spezifität betrug 98 % (95 % CI; 86 – 100 %) und der negative Vorhersagewert 100 %. Kontrastmittel-Nebenwirkungen wurden nicht beobachtet.

Schlussfolgerung: Diese Befunde zeigen den Nutzen von CEUS hinsichtlich der Charakterisierung von ungeklärten B-Bild Befunden bei pädiatrischen Patienten mit FLL mit der Möglichkeit, die Strahlenexposition zu verringern.

Key words

ultrasonography - contrast media - liver - neoplasms - paediatrics

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