title: Contrast-enhanced ultrasound for assessment of therapeutic response after percutaneous radiofrequency ablation of small renal tumors.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of contrast-enhanced ultrasound (CEUS) in the assessment of therapeutic response, after percutaneous radiofrequency ablation (RFA) of small renal tumors.
  
  
  METHODS
  Twenty patients (12 men, 8 women; median age, 77.4 years; median tumor size, 2.7 cm) were treated with RFA. All patients were examined by contrast-enhanced computed tomography (CECT), followed by CEUS one week later. Tumor enhancement characteristics and thickness of the enhancing area in viable lesions were evaluated.
  
  
  RESULTS
  Median time from RFA to diagnostic imaging was 16.8 months. All 20 patients underwent CT. CEUS was finally performed in only 14 out of 20 patients (70%), since 2 out of 6 had contraindications for the application of a US contrast agent. Also, one patient refused the application and a further 3 had tumors that were impossible to differentiate adequately on the conventional B-mode US, in order to satisfactorily monitor the contrast enhancement. CEUS showed a complete response in 9 out of 14 (64.3%) patients, residual tumor in 4 (28.6%) and tumor progression in 1 patient (7.1%). Median thickness of the enhancing area on CECT and CEUS was 20 mm vs 17 mm, respectively, with no statistically significant difference in the thickness (t =-0.816, p=0.461) between both modalities. The concordance between CECT and CEUS in the assessment of tumor response and detection of residual vascular enhancement was 100%.
  
  
  CONCLUSIONS
  CEUS is an effective and safe imaging modality in assessing the therapeutic response, after percutaneous radiofrequency ablation of small renal tumors. Disadvantages can be overcome with improved CEUS technology.
authors: Clinical Institute of Radiology, University Medical Centre, Ljubljana, Slovenia.
authors: Manca
authors: M
authors: Garbajs
authors: Peter
authors: P
authors: Popovic
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D003287:Contrast Media