Is Contrast-Enhanced US Alternative to Spiral CT in the Assessment of Treatment Outcome of Radiofrequency Ablation in Hepatocellular Carcinoma?

Zusammenfassung

Ziel: Die vorliegende Studie diente dem Ziel, die Wertigkeit der Kontrastmittelsonografie mit niedrigem mechanischem Index bei der Beurteilung des Therapieerfolgs der perkutanen Radiofrequenzablation des hepatozellulären Karzinoms im Vergleich mit dem 4-zeiligen Spiral-CT zu ermitteln. Material und Methoden: 100 aufeinanderfolgend vorgestellte Patienten (65 Männer und 35 Frauen, Alter: 62 – 76 Jahre) mit hepatozellulärem Karzinom (mittlere Tumorgröße 3,7 ± 1,1 cm SD) wurden mit gekühlter Radiofrequenzablation behandelt. Das Behandlungsergebnis wurde einen Monat nach dem Eingriff mit kontrastmittelgestütztem Dreiphasen-Spiral-CT sowie der Kontrastmittelsonografie mit niedrigem mechanischem Index nach Injektion eines Bolus von 2,4 ml SonoVue (Bracco, Mailand) untersucht. 60 von 100 Patienten wurden 3 Monate später nachuntersucht. Die kontrastgestützten Sonografieaufnahmen wurden von zwei verblindeten Radiologen zusammen begutachtet. Sensitivität, Spezifität, NPV und PPV der Kontrastmittelsonografie wurden ermittelt. Ergebnisse: Nach der Behandlung stellte die Kontrastmittelsonografie eine persistierende Signalverstärkung bei 24 Patienten dar (24 %), wohingegen bei den übrigen 76 Patienten (76 %) keine Anreicherung innerhalb des Tumors festgestellt werden konnte. Im Vergleich mit dem CT als Goldstandard lagen Sensitivität, Spezifität, NPV, and PPV der Kontrastmittelsonografie bei 92,3 % (95 % CI = 75,9 – 97,9 %), 100 % (95 % CI = 95,2 – 100 %), 97,4 % (95 % CI = 91,1 – 99,3 %) und 100 % (95 % CI = 86,2 – 100 %). Schlussfolgerung: Die Kontrastmittelsonografie mit niedrigem mechanischem Index und der Anwendung von SonoVue stellt ein brauchbares Instrument für die Bewertung des Therapieerfolgs der Radiofrequenzablation beim hepatozellulären Karzinom dar mit einer Genauigkeit, die der des 4-zeiligen Spiral-CT vergleichbar ist.

Abstract

Purpose: The present study was conducted to assess the efficacy of contrast-enhanced ultrasound with low mechanical index in evaluating the response of percutaneous radiofrequency ablation treatment of hepatocellular carcinoma by comparing it with 4-row spiral computed tomography. Materials and Methods: 100 consecutive patients (65 men and 35 women; age range: 62 – 76 years) with solitary hepatocellular carcinomas (mean lesion diameter: 3.7 cm ± 1.1 cm SD) underwent internally cooled radiofrequency ablation. Therapeutic response was evaluated at one month after the treatment with triple-phasic contrast-enhanced spiral CT and low-mechanical index contrast-enhanced ultrasound following bolus injection of 2.4 ml of Sonovue (Bracco, Milan). 60 out of 100 patients were followed up for another 3 months. Contrast-enhanced sonographic studies were reviewed by two blinded radiologists in consensus. Sensitivity, specificity, NPV and PPV of contrast-enhanced ultrasound examination were determined. Results: After treatment, contrast-enhanced ultrasound identified persistent signal enhancement in 24 patients (24 %), whereas no intratumoral enhancement was detected in the remaining 76 patients (76 %). Using CT imaging as gold standard, the sensitivity, specificity, NPV, and PPV of contrast enhanced ultrasound were 92.3 % (95 % CI = 75.9 – 97.9 %), 100 % (95 % CI = 95.2 – 100 %), 97.4 % (95 % CI = 91.1 – 99.3 %), and 100 % (95 % CI = 86.2 – 100 %). Conclusion: Contrast-enhanced ultrasound with low mechanical index using Sonovue is a feasible tool in evaluating the response of hepatocellular carcinoma to radiofrequency ablation. Accuracy is comparable to 4-row spiral CT.

Key words

neoplasms - abdomen - CT - ultrasound - radiofrequency

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