Comparative study of conventional US, contrast enhanced US and enhanced MR for the follow-up of prostatic radiofrequency ablation

Abstract

Abstract. The aim of the present study was to evaluate and compare the effectiveness of different imaging methods during follow-up of prostatic radiofrequency ablation. Prostatic radiofrequency ablation (RFA) was performed in 20 healthy beagle dogs. Various imaging examinations were used to monitor the results of RFA, including conventional ultrasound (US), contrast enhanced ultrasound (CEUS) and enhanced magnetic resonance (MR). Imaging exams were performed at five phases: Immediately following RFA, one week later, one month later, three months later and six months later. The morphology for each imaging test and histological results were recorded and compared in each phase. Based on the actual results from autopsy, the accuracy of those imaging exams was evaluated. The canine prostate gland demonstrated typical coagulative necrosis immediately following RFA. The lesion would develop into stable cyst if no other complications occurred within the six-month follow-up. Regarding the RFA lesion volume measurement and the reflection of pathological changes, conventional US was not able to accurately measure the volume of RFA lesion and missed many more details concerning the RFA-treated area than CEUS and MR during the three months. The results from CEUS exhibited comparable accuracy to those from enhanced MR at each phase. However, there were no significant differences in the results from US, CEUS and MR at six months, which may contribute to the complete formation of lesion cyst. In the early phase, conventional US was not sufficient for evaluating the efficacy of RFA. Enhanced US and MR provided clear images and accurate information. However, CEUS has the advantage of being more economical, using more convenient equipment and faster scanning, thus identifying it as the more feasible choice. Furthermore, no notable advantages were observed among any image examinations in the long-term follow-up. IntroductionThe worldwide incidence of prostate cancer has been rising in recent years and prostate cancer has become a major threat for aged male populations. Each year, ~914,000 new cases are diagnosed, and 258,000 cases lead to mortality (1). At present, radical prostatectomy is the standard treatment for localized prostate cancer; however, this surgical procedure may have a notable negative impact on patients, such as incontinence or erectile dysfunction (2). Radiofrequency ablation (RFA) is gaining popularity as a method of treating prostate diseases, as it is an interventional therapy that causes less trauma, quicker recovery and fewer complications (3).In order to obtain results from RFA, the use of a real-time prostatic imaging monitor is necessary. At present, conventional transrectal ultrasound (US) is typically used for guiding prostate RFA, allowing the procedure to be visualized in real time. However, the indication of RFA is vague and the accuracy of imaging results is not reliable (3,4). In addition to conventional US, contrast enhanced US (CEUS) and enhanced magnetic resonance (MR) have also been considered ...

Lesions of canine prostate underwent laser ablation, radiofrequency ablation, and microwave ablation: Lesions’ shapes and clinical significances

“…Pathological examinations have demonstrated that RFA and MWA could induce coagulative necrosis. The high-power MWA (45 W/180 s) results in he penetration of ablation through the prostate, suggesting that appropriate power and time should be taken for the treatment into consideration [10,11]. To date, no studies have reported which of the three ablation techniques should be selected for BPH and PCa.…”

Contrast enhanced ultrasound of the prostate. New role in the evaluation of loco-regional therapy of prostate tumors

“…Moreover, in comparison to MRI it is easier to perform, can be implemented during the procedure and has a lower cost [14]. A very recent study has demonstrated the CEUS has similar accuracy as MRI at several time intervals after RFA [14]. The same results were obtained after irreversible electroporation [15].…”

“…Due to it's lower invasiveness, quicker recovery and fewer complications RFA is gaining popularity in the treatment of prostate diseases especially PCa [14]. MRI displays the highest sensitivity to soft tissue so it has been used mostly to evaluate the results of RFA and other local therapies [14].…”

“…MRI displays the highest sensitivity to soft tissue so it has been used mostly to evaluate the results of RFA and other local therapies [14]. By depicting the microvasculature CEUS has the ability to detect the treated tumor as an unenhanced area and to monitor it over time.…”

“…By depicting the microvasculature CEUS has the ability to detect the treated tumor as an unenhanced area and to monitor it over time. Moreover, in comparison to MRI it is easier to perform, can be implemented during the procedure and has a lower cost [14]. A very recent study has demonstrated the CEUS has similar accuracy as MRI at several time intervals after RFA [14].…”