Role of contrast-enhanced ultrasound in evaluating the efficiency of ultrasound guided percutaneous microwave ablation in patients with renal cell carcinoma
Objective: To evaluate the efficiency and feasibility of contrast-enhanced ultrasound (CEUS) in assessing of renal cell carcinomas (RCCs) following US-guided percutaneous microwave ablation (MWA).
Materials and Methods The CEUS results of the third day after ablation were compared with biopsy results and contrast-enhanced CT/MRI results simultaneously. The follow-up was administrated by CEUS and CT/MRI at 1, 3, 6 months and every 6 months subsequently. Combination of the clinical follow-up results and CT/MRI imaging results were reference standard of CEUS results for the long-term therapeutic effect.
Results: Eighty-three lesions with diameter 3.2±1.6cm (rang 0.6-7.8cm) were ablated. On the third day after MWA, CEUS showed 68 of 83 (81.9%) were successfully ablated and confirmed by 72 hours contrast-enhanced CT/MRI after MWA. Fifteen of 83(18.1%) appeared residual tumor on CEUS, then were performed biopsy and CEUS-guided ablation. Among 15 patients, 13 (86.7%) were verified with residual tumor by biopsy results. The sensitivity, specificity, accuracy, positive and negative predictive value were 100%, 97.1%, 97.6%, 86.7% and 100%, respectively. Seventy-six patients survived in the follow-up ranged from 3 to 74 (median 26) months. During the follow-up, the CEUS showed local recurrence in 7 patients, and six of them achieved consistent results on CEUS and CT/MRI imaging. The sensitivity, specificity, accuracy, positive and negative predictive value for detecting recurrence tumor were 85.7%, 98.7%, 97.6%, 85.7% and 98.7%, respectively.