Accuracy of contrast - enhanced ultrasound for tumor response after RFA / TACE in malignant focal liver lesions in comparison with CT / MRI in a tertiary Swiss GI center
Conference Paper/Poster - Sep 20, 2014
Sawatzki Mikael, Hechelhammer Lukas, Semela David
Background: Contrast-enhanced-ultrasound (CEUS) seems to be accurate for follow-up after radiofrequency ablation (RFA) in HCC or liver metastasis as well as after transarterial chemo-embolization (TACE) in HCC (1,2,3). CEUS is easily available, safe and cost-effective without exposure to radiation, risk of renal insufficiency or thyreotoxicosis. Severe adverse effects are very uncommon (0,06 - 0,4%) (4, 5). Our aim was to assess the response/relapse of malignant focal liver lesions (FLL) after RFA or TACE by CEUS in comparison to CT/MRI.
Methods: We analysed all CEUS between 1/2011-11/2013 performed by three examinators (level II of training according to European Federation Society for Ultrasound) on two ultrasound devices (Acuson Sequoia 512R, Siemens and Preirus Hi Vision R, Hitatchi) after RFA and/or TACE in comparison to CT/MRI (with iv contrast application). All patients were examined according to international guidelines and good clinical practice recommendations (6) with intravenous application of sulphur hexafluoride microbubbles (SonoVueR, Bracco). Postinterventional intratumoral arterial enhancement was interpretated as tumor vitality/relapse, wash out reinforced this finding (Figure 1). Standard of reference (SOR) were the convergent results of CEUS with CT or MRI with follow-up.
Results: In all 20 patients (17 HCC and one cholangio-carcinoma all with cirrhosis and 2 liver metastasis of colorectal carcinoma with median age of 43-86 years), no complications occurred after CEUS. CEUS could be compared with CT/MRI in 40 examinations after 30 interventions (RFA13/TACE17) with a median follow of 6,7 months. Controlls were performed one month and then every three months after interventions. In four different cases CEUS and CT/MRI could not demonstrate tumor vitality after incomplete RFA/TACE. This is described as equal sensitivity with 75% and negative predictive value (npV) with 85-86% (table 1). CEUS could avoid one false positive MRI result after one month (specificity and positive predictive value (ppV) 100%), where this reactive peripheral hypervascularisation was confirmed by the following MRI’s.
Conclusions: In our setting CEUS is practicable with no adverse effects and good accuracy of 90% to determine tumor response after RFA/TACE. CEUS is not inferior to CT/MRI. Combination of CEUS with CT/MRI could avoid 20% of false negative results (tumor vitality/relapse). Rapidity and cost-effectiveness could be an advantage of CEUS.