RESUMO
PURPOSE: To retrospectively assess the diagnostic accuracy of immediate post-procedural CEUS, 24-h CEUS, and 24-h CT in verifying the effectiveness of thermal ablation of liver tumors ablation, using the combined results of 3-month post-procedure CEUS and MDCT as the reference standard. MATERIALS AND METHODS: From our database, we selected patients who had immediate post-procedural CEUS and 24-h CEUS and MDCT examinations after undergoing thermal ablation of a liver tumor between January 2009 and March 2010. The study population consisted of 53 subjects and 55 tumors (44 HCC and 11 metastasis) were evaluated. Thirty-seven tumors were treated with radiofrequency and 18 with microwave ablation. Post-procedural CEUS, 24-h CEUS and MDCT, and 3-month follow-up CEUS and MDCT images were blindly reviewed by two radiologists, who measured the size of the ablation area on the post-procedural and 24-h studies. They also evaluated the ability of each of these three index tests to predict the outcome (residual tumor vs. no residual tumor) using imaging studies done at the 3-month follow-up as the reference standard. RESULTS: Mean tumor diameter on preablation CEUS (the day before treatment) was 20 ± 9 mm. Mean diameter of the necrotic area was 29 ± 9 mm on post-procedural CEUS, 34 ± 11 mm on 24-h CEUS, and 36 ± 11 mm on 24-h MDCT. Diameters of the necrotic area (mean and maximum) on post-procedural CEUS were significantly smaller than those measured on 24-h CEUS or 24-h MDCT, which were not significantly different. For predicting the presence of residual tumor at the 3-month follow-up, post-procedural CEUS, 24-h CEUS, and 24-h MDCT displayed sensitivity of 33%, 33%, and 42%; specificity of 92%, 97%, and 97%; negative predictive value of 84%, 85%, and 83%. The accuracy parameters of these three imaging modalities were not significantly different from one another. CONCLUSIONS: In patients undergoing thermal ablation for liver tumors, the immediate post-procedural CEUS seems comparable to 24-h CEUS and MDCT in terms of detecting residual disease.
RESUMO
Three methods are currently used to identify vesicoureteral reflux (VUR) in children, namely, radiographic voiding cystourethrography, radionuclide voiding cystography and, more recently, echo-enhanced voiding urosonography (VUS). Recent advances in tissue-harmonic and contrast-specific imaging techniques, together with the development of second-generation contrast agents, have improved the potential of ultrasonography both in the diagnosis and grading of VUR in children. Today, VUS is able to accurately assess the grade of reflux and the state of the urethra, previously considered fundamental limitations to the extensive use of this technique. The aim of our paper is to review the role of ultrasonography in the diagnosis of VUR, from the initial experiences up to the recent use of second-generation microbubbles combined with contrast-specific low-mechanical-index software. We discuss the advantages and limits of VUS with respect to radiographic and radionuclide imaging in the light of an analysis of the most recent literature, and we described the new VUS study technique using second-generation contrast media. Growing requests by paediatric nephrologists and surgeons require that even general radiologists become familiar with this technique.
